1 /*
2 * Copyright (c) 1996, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.io;
27
28 import java.io.ObjectStreamClass.WeakClassKey;
29 import java.lang.ref.ReferenceQueue;
30 import java.security.AccessController;
31 import java.security.PrivilegedAction;
32 import java.util.ArrayList;
33 import java.util.Arrays;
34 import java.util.List;
35 import java.util.concurrent.ConcurrentHashMap;
36 import java.util.concurrent.ConcurrentMap;
37 import static java.io.ObjectStreamClass.processQueue;
38 import sun.reflect.misc.ReflectUtil;
39
40 /**
41 * An ObjectOutputStream writes primitive data types and graphs of Java objects
42 * to an OutputStream. The objects can be read (reconstituted) using an
43 * ObjectInputStream. Persistent storage of objects can be accomplished by
44 * using a file for the stream. If the stream is a network socket stream, the
45 * objects can be reconstituted on another host or in another process.
46 *
47 * <p>Only objects that support the java.io.Serializable interface can be
48 * written to streams. The class of each serializable object is encoded
49 * including the class name and signature of the class, the values of the
50 * object's fields and arrays, and the closure of any other objects referenced
51 * from the initial objects.
52 *
53 * <p>The method writeObject is used to write an object to the stream. Any
54 * object, including Strings and arrays, is written with writeObject. Multiple
55 * objects or primitives can be written to the stream. The objects must be
56 * read back from the corresponding ObjectInputstream with the same types and
57 * in the same order as they were written.
58 *
59 * <p>Primitive data types can also be written to the stream using the
60 * appropriate methods from DataOutput. Strings can also be written using the
61 * writeUTF method.
62 *
63 * <p>The default serialization mechanism for an object writes the class of the
64 * object, the class signature, and the values of all non-transient and
65 * non-static fields. References to other objects (except in transient or
66 * static fields) cause those objects to be written also. Multiple references
67 * to a single object are encoded using a reference sharing mechanism so that
68 * graphs of objects can be restored to the same shape as when the original was
69 * written.
70 *
71 * <p>For example to write an object that can be read by the example in
72 * ObjectInputStream:
73 * <br>
74 * <pre>
75 * FileOutputStream fos = new FileOutputStream("t.tmp");
76 * ObjectOutputStream oos = new ObjectOutputStream(fos);
77 *
78 * oos.writeInt(12345);
79 * oos.writeObject("Today");
80 * oos.writeObject(new Date());
81 *
82 * oos.close();
83 * </pre>
84 *
85 * <p>Classes that require special handling during the serialization and
86 * deserialization process must implement special methods with these exact
87 * signatures:
88 * <br>
89 * <pre>
90 * private void readObject(java.io.ObjectInputStream stream)
91 * throws IOException, ClassNotFoundException;
92 * private void writeObject(java.io.ObjectOutputStream stream)
93 * throws IOException
94 * private void readObjectNoData()
95 * throws ObjectStreamException;
96 * </pre>
97 *
98 * <p>The writeObject method is responsible for writing the state of the object
99 * for its particular class so that the corresponding readObject method can
100 * restore it. The method does not need to concern itself with the state
101 * belonging to the object's superclasses or subclasses. State is saved by
102 * writing the individual fields to the ObjectOutputStream using the
103 * writeObject method or by using the methods for primitive data types
104 * supported by DataOutput.
105 *
106 * <p>Serialization does not write out the fields of any object that does not
107 * implement the java.io.Serializable interface. Subclasses of Objects that
108 * are not serializable can be serializable. In this case the non-serializable
109 * class must have a no-arg constructor to allow its fields to be initialized.
110 * In this case it is the responsibility of the subclass to save and restore
111 * the state of the non-serializable class. It is frequently the case that the
112 * fields of that class are accessible (public, package, or protected) or that
113 * there are get and set methods that can be used to restore the state.
114 *
115 * <p>Serialization of an object can be prevented by implementing writeObject
116 * and readObject methods that throw the NotSerializableException. The
117 * exception will be caught by the ObjectOutputStream and abort the
118 * serialization process.
119 *
120 * <p>Implementing the Externalizable interface allows the object to assume
121 * complete control over the contents and format of the object's serialized
122 * form. The methods of the Externalizable interface, writeExternal and
123 * readExternal, are called to save and restore the objects state. When
124 * implemented by a class they can write and read their own state using all of
125 * the methods of ObjectOutput and ObjectInput. It is the responsibility of
126 * the objects to handle any versioning that occurs.
127 *
128 * <p>Enum constants are serialized differently than ordinary serializable or
129 * externalizable objects. The serialized form of an enum constant consists
130 * solely of its name; field values of the constant are not transmitted. To
131 * serialize an enum constant, ObjectOutputStream writes the string returned by
132 * the constant's name method. Like other serializable or externalizable
133 * objects, enum constants can function as the targets of back references
134 * appearing subsequently in the serialization stream. The process by which
135 * enum constants are serialized cannot be customized; any class-specific
136 * writeObject and writeReplace methods defined by enum types are ignored
137 * during serialization. Similarly, any serialPersistentFields or
138 * serialVersionUID field declarations are also ignored--all enum types have a
139 * fixed serialVersionUID of 0L.
140 *
141 * <p>Primitive data, excluding serializable fields and externalizable data, is
142 * written to the ObjectOutputStream in block-data records. A block data record
143 * is composed of a header and data. The block data header consists of a marker
144 * and the number of bytes to follow the header. Consecutive primitive data
145 * writes are merged into one block-data record. The blocking factor used for
146 * a block-data record will be 1024 bytes. Each block-data record will be
147 * filled up to 1024 bytes, or be written whenever there is a termination of
148 * block-data mode. Calls to the ObjectOutputStream methods writeObject,
149 * defaultWriteObject and writeFields initially terminate any existing
150 * block-data record.
151 *
152 * @author Mike Warres
153 * @author Roger Riggs
154 * @see java.io.DataOutput
155 * @see java.io.ObjectInputStream
156 * @see java.io.Serializable
157 * @see java.io.Externalizable
158 * @see <a href="../../../platform/serialization/spec/output.html">Object Serialization Specification, Section 2, Object Output Classes</a>
159 * @since JDK1.1
160 */
161 public class ObjectOutputStream
162 extends OutputStream implements ObjectOutput, ObjectStreamConstants
163 {
164
165 private static class Caches {
166 /** cache of subclass security audit results */
167 static final ConcurrentMap<WeakClassKey,Boolean> subclassAudits =
168 new ConcurrentHashMap<>();
169
170 /** queue for WeakReferences to audited subclasses */
171 static final ReferenceQueue<Class<?>> subclassAuditsQueue =
172 new ReferenceQueue<>();
173 }
174
175 /** filter stream for handling block data conversion */
176 private final BlockDataOutputStream bout;
177 /** obj -> wire handle map */
178 private final HandleTable handles;
179 /** obj -> replacement obj map */
180 private final ReplaceTable subs;
181 /** stream protocol version */
182 private int protocol = PROTOCOL_VERSION_2;
183 /** recursion depth */
184 private int depth;
185
186 /** buffer for writing primitive field values */
187 private byte[] primVals;
188
189 /** if true, invoke writeObjectOverride() instead of writeObject() */
190 private final boolean enableOverride;
191 /** if true, invoke replaceObject() */
192 private boolean enableReplace;
193
194 // values below valid only during upcalls to writeObject()/writeExternal()
195 /**
196 * Context during upcalls to class-defined writeObject methods; holds
197 * object currently being serialized and descriptor for current class.
198 * Null when not during writeObject upcall.
199 */
200 private SerialCallbackContext curContext;
201 /** current PutField object */
202 private PutFieldImpl curPut;
203
204 /** custom storage for debug trace info */
205 private final DebugTraceInfoStack debugInfoStack;
206
207 /**
208 * value of "sun.io.serialization.extendedDebugInfo" property,
209 * as true or false for extended information about exception's place
210 */
211 private static final boolean extendedDebugInfo =
212 java.security.AccessController.doPrivileged(
213 new sun.security.action.GetBooleanAction(
214 "sun.io.serialization.extendedDebugInfo")).booleanValue();
215
216 /**
217 * Creates an ObjectOutputStream that writes to the specified OutputStream.
218 * This constructor writes the serialization stream header to the
219 * underlying stream; callers may wish to flush the stream immediately to
220 * ensure that constructors for receiving ObjectInputStreams will not block
221 * when reading the header.
222 *
223 * <p>If a security manager is installed, this constructor will check for
224 * the "enableSubclassImplementation" SerializablePermission when invoked
225 * directly or indirectly by the constructor of a subclass which overrides
226 * the ObjectOutputStream.putFields or ObjectOutputStream.writeUnshared
227 * methods.
228 *
229 * @param out output stream to write to
230 * @throws IOException if an I/O error occurs while writing stream header
231 * @throws SecurityException if untrusted subclass illegally overrides
232 * security-sensitive methods
233 * @throws NullPointerException if <code>out</code> is <code>null</code>
234 * @since 1.4
235 * @see ObjectOutputStream#ObjectOutputStream()
236 * @see ObjectOutputStream#putFields()
237 * @see ObjectInputStream#ObjectInputStream(InputStream)
238 */
239 public ObjectOutputStream(OutputStream out) throws IOException {
240 verifySubclass();
241 bout = new BlockDataOutputStream(out);
242 handles = new HandleTable(10, (float) 3.00);
243 subs = new ReplaceTable(10, (float) 3.00);
244 enableOverride = false;
245 writeStreamHeader();
246 bout.setBlockDataMode(true);
247 if (extendedDebugInfo) {
248 debugInfoStack = new DebugTraceInfoStack();
249 } else {
250 debugInfoStack = null;
251 }
252 }
253
254 /**
255 * Provide a way for subclasses that are completely reimplementing
256 * ObjectOutputStream to not have to allocate private data just used by
257 * this implementation of ObjectOutputStream.
258 *
259 * <p>If there is a security manager installed, this method first calls the
260 * security manager's <code>checkPermission</code> method with a
261 * <code>SerializablePermission("enableSubclassImplementation")</code>
262 * permission to ensure it's ok to enable subclassing.
263 *
264 * @throws SecurityException if a security manager exists and its
265 * <code>checkPermission</code> method denies enabling
266 * subclassing.
267 * @throws IOException if an I/O error occurs while creating this stream
268 * @see SecurityManager#checkPermission
269 * @see java.io.SerializablePermission
270 */
271 protected ObjectOutputStream() throws IOException, SecurityException {
272 SecurityManager sm = System.getSecurityManager();
273 if (sm != null) {
274 sm.checkPermission(SUBCLASS_IMPLEMENTATION_PERMISSION);
275 }
276 bout = null;
277 handles = null;
278 subs = null;
279 enableOverride = true;
280 debugInfoStack = null;
281 }
282
283 /**
284 * Specify stream protocol version to use when writing the stream.
285 *
286 * <p>This routine provides a hook to enable the current version of
287 * Serialization to write in a format that is backwards compatible to a
288 * previous version of the stream format.
289 *
290 * <p>Every effort will be made to avoid introducing additional
291 * backwards incompatibilities; however, sometimes there is no
292 * other alternative.
293 *
294 * @param version use ProtocolVersion from java.io.ObjectStreamConstants.
295 * @throws IllegalStateException if called after any objects
296 * have been serialized.
297 * @throws IllegalArgumentException if invalid version is passed in.
298 * @throws IOException if I/O errors occur
299 * @see java.io.ObjectStreamConstants#PROTOCOL_VERSION_1
300 * @see java.io.ObjectStreamConstants#PROTOCOL_VERSION_2
301 * @since 1.2
302 */
303 public void useProtocolVersion(int version) throws IOException {
304 if (handles.size() != 0) {
305 // REMIND: implement better check for pristine stream?
306 throw new IllegalStateException("stream non-empty");
307 }
308 switch (version) {
309 case PROTOCOL_VERSION_1:
310 case PROTOCOL_VERSION_2:
311 protocol = version;
312 break;
313
314 default:
315 throw new IllegalArgumentException(
316 "unknown version: " + version);
317 }
318 }
319
320 /**
321 * Write the specified object to the ObjectOutputStream. The class of the
322 * object, the signature of the class, and the values of the non-transient
323 * and non-static fields of the class and all of its supertypes are
324 * written. Default serialization for a class can be overridden using the
325 * writeObject and the readObject methods. Objects referenced by this
326 * object are written transitively so that a complete equivalent graph of
327 * objects can be reconstructed by an ObjectInputStream.
328 *
329 * <p>Exceptions are thrown for problems with the OutputStream and for
330 * classes that should not be serialized. All exceptions are fatal to the
331 * OutputStream, which is left in an indeterminate state, and it is up to
332 * the caller to ignore or recover the stream state.
333 *
334 * @throws InvalidClassException Something is wrong with a class used by
335 * serialization.
336 * @throws NotSerializableException Some object to be serialized does not
337 * implement the java.io.Serializable interface.
338 * @throws IOException Any exception thrown by the underlying
339 * OutputStream.
340 */
341 public final void writeObject(Object obj) throws IOException {
342 if (enableOverride) {
343 writeObjectOverride(obj);
344 return;
345 }
346 try {
347 writeObject0(obj, false);
348 } catch (IOException ex) {
349 if (depth == 0) {
350 writeFatalException(ex);
351 }
352 throw ex;
353 }
354 }
355
356 /**
357 * Method used by subclasses to override the default writeObject method.
358 * This method is called by trusted subclasses of ObjectInputStream that
359 * constructed ObjectInputStream using the protected no-arg constructor.
360 * The subclass is expected to provide an override method with the modifier
361 * "final".
362 *
363 * @param obj object to be written to the underlying stream
364 * @throws IOException if there are I/O errors while writing to the
365 * underlying stream
366 * @see #ObjectOutputStream()
367 * @see #writeObject(Object)
368 * @since 1.2
369 */
370 protected void writeObjectOverride(Object obj) throws IOException {
371 }
372
373 /**
374 * Writes an "unshared" object to the ObjectOutputStream. This method is
375 * identical to writeObject, except that it always writes the given object
376 * as a new, unique object in the stream (as opposed to a back-reference
377 * pointing to a previously serialized instance). Specifically:
378 * <ul>
379 * <li>An object written via writeUnshared is always serialized in the
380 * same manner as a newly appearing object (an object that has not
381 * been written to the stream yet), regardless of whether or not the
382 * object has been written previously.
383 *
384 * <li>If writeObject is used to write an object that has been previously
385 * written with writeUnshared, the previous writeUnshared operation
386 * is treated as if it were a write of a separate object. In other
387 * words, ObjectOutputStream will never generate back-references to
388 * object data written by calls to writeUnshared.
389 * </ul>
390 * While writing an object via writeUnshared does not in itself guarantee a
391 * unique reference to the object when it is deserialized, it allows a
392 * single object to be defined multiple times in a stream, so that multiple
393 * calls to readUnshared by the receiver will not conflict. Note that the
394 * rules described above only apply to the base-level object written with
395 * writeUnshared, and not to any transitively referenced sub-objects in the
396 * object graph to be serialized.
397 *
398 * <p>ObjectOutputStream subclasses which override this method can only be
399 * constructed in security contexts possessing the
400 * "enableSubclassImplementation" SerializablePermission; any attempt to
401 * instantiate such a subclass without this permission will cause a
402 * SecurityException to be thrown.
403 *
404 * @param obj object to write to stream
405 * @throws NotSerializableException if an object in the graph to be
406 * serialized does not implement the Serializable interface
407 * @throws InvalidClassException if a problem exists with the class of an
408 * object to be serialized
409 * @throws IOException if an I/O error occurs during serialization
410 * @since 1.4
411 */
412 public void writeUnshared(Object obj) throws IOException {
413 try {
414 writeObject0(obj, true);
415 } catch (IOException ex) {
416 if (depth == 0) {
417 writeFatalException(ex);
418 }
419 throw ex;
420 }
421 }
422
423 /**
424 * Write the non-static and non-transient fields of the current class to
425 * this stream. This may only be called from the writeObject method of the
426 * class being serialized. It will throw the NotActiveException if it is
427 * called otherwise.
428 *
429 * @throws IOException if I/O errors occur while writing to the underlying
430 * <code>OutputStream</code>
431 */
432 public void defaultWriteObject() throws IOException {
433 SerialCallbackContext ctx = curContext;
434 if (ctx == null) {
435 throw new NotActiveException("not in call to writeObject");
436 }
437 Object curObj = ctx.getObj();
438 ObjectStreamClass curDesc = ctx.getDesc();
439 bout.setBlockDataMode(false);
440 defaultWriteFields(curObj, curDesc);
441 bout.setBlockDataMode(true);
442 }
443
444 /**
445 * Retrieve the object used to buffer persistent fields to be written to
446 * the stream. The fields will be written to the stream when writeFields
447 * method is called.
448 *
449 * @return an instance of the class Putfield that holds the serializable
450 * fields
451 * @throws IOException if I/O errors occur
452 * @since 1.2
453 */
454 public ObjectOutputStream.PutField putFields() throws IOException {
455 if (curPut == null) {
456 SerialCallbackContext ctx = curContext;
457 if (ctx == null) {
458 throw new NotActiveException("not in call to writeObject");
459 }
460 ctx.checkAndSetUsed();
461 ObjectStreamClass curDesc = ctx.getDesc();
462 curPut = new PutFieldImpl(curDesc);
463 }
464 return curPut;
465 }
466
467 /**
468 * Write the buffered fields to the stream.
469 *
470 * @throws IOException if I/O errors occur while writing to the underlying
471 * stream
472 * @throws NotActiveException Called when a classes writeObject method was
473 * not called to write the state of the object.
474 * @since 1.2
475 */
476 public void writeFields() throws IOException {
477 if (curPut == null) {
478 throw new NotActiveException("no current PutField object");
479 }
480 bout.setBlockDataMode(false);
481 curPut.writeFields();
482 bout.setBlockDataMode(true);
483 }
484
485 /**
486 * Reset will disregard the state of any objects already written to the
487 * stream. The state is reset to be the same as a new ObjectOutputStream.
488 * The current point in the stream is marked as reset so the corresponding
489 * ObjectInputStream will be reset at the same point. Objects previously
490 * written to the stream will not be referred to as already being in the
491 * stream. They will be written to the stream again.
492 *
493 * @throws IOException if reset() is invoked while serializing an object.
494 */
495 public void reset() throws IOException {
496 if (depth != 0) {
497 throw new IOException("stream active");
498 }
499 bout.setBlockDataMode(false);
500 bout.writeByte(TC_RESET);
501 clear();
502 bout.setBlockDataMode(true);
503 }
504
505 /**
506 * Subclasses may implement this method to allow class data to be stored in
507 * the stream. By default this method does nothing. The corresponding
508 * method in ObjectInputStream is resolveClass. This method is called
509 * exactly once for each unique class in the stream. The class name and
510 * signature will have already been written to the stream. This method may
511 * make free use of the ObjectOutputStream to save any representation of
512 * the class it deems suitable (for example, the bytes of the class file).
513 * The resolveClass method in the corresponding subclass of
514 * ObjectInputStream must read and use any data or objects written by
515 * annotateClass.
516 *
517 * @param cl the class to annotate custom data for
518 * @throws IOException Any exception thrown by the underlying
519 * OutputStream.
520 */
521 protected void annotateClass(Class<?> cl) throws IOException {
522 }
523
524 /**
525 * Subclasses may implement this method to store custom data in the stream
526 * along with descriptors for dynamic proxy classes.
527 *
528 * <p>This method is called exactly once for each unique proxy class
529 * descriptor in the stream. The default implementation of this method in
530 * <code>ObjectOutputStream</code> does nothing.
531 *
532 * <p>The corresponding method in <code>ObjectInputStream</code> is
533 * <code>resolveProxyClass</code>. For a given subclass of
534 * <code>ObjectOutputStream</code> that overrides this method, the
535 * <code>resolveProxyClass</code> method in the corresponding subclass of
536 * <code>ObjectInputStream</code> must read any data or objects written by
537 * <code>annotateProxyClass</code>.
538 *
539 * @param cl the proxy class to annotate custom data for
540 * @throws IOException any exception thrown by the underlying
541 * <code>OutputStream</code>
542 * @see ObjectInputStream#resolveProxyClass(String[])
543 * @since 1.3
544 */
545 protected void annotateProxyClass(Class<?> cl) throws IOException {
546 }
547
548 /**
549 * This method will allow trusted subclasses of ObjectOutputStream to
550 * substitute one object for another during serialization. Replacing
551 * objects is disabled until enableReplaceObject is called. The
552 * enableReplaceObject method checks that the stream requesting to do
553 * replacement can be trusted. The first occurrence of each object written
554 * into the serialization stream is passed to replaceObject. Subsequent
555 * references to the object are replaced by the object returned by the
556 * original call to replaceObject. To ensure that the private state of
557 * objects is not unintentionally exposed, only trusted streams may use
558 * replaceObject.
559 *
560 * <p>The ObjectOutputStream.writeObject method takes a parameter of type
561 * Object (as opposed to type Serializable) to allow for cases where
562 * non-serializable objects are replaced by serializable ones.
563 *
564 * <p>When a subclass is replacing objects it must insure that either a
565 * complementary substitution must be made during deserialization or that
566 * the substituted object is compatible with every field where the
567 * reference will be stored. Objects whose type is not a subclass of the
568 * type of the field or array element abort the serialization by raising an
569 * exception and the object is not be stored.
570 *
571 * <p>This method is called only once when each object is first
572 * encountered. All subsequent references to the object will be redirected
573 * to the new object. This method should return the object to be
574 * substituted or the original object.
575 *
576 * <p>Null can be returned as the object to be substituted, but may cause
577 * NullReferenceException in classes that contain references to the
578 * original object since they may be expecting an object instead of
579 * null.
580 *
581 * @param obj the object to be replaced
582 * @return the alternate object that replaced the specified one
583 * @throws IOException Any exception thrown by the underlying
584 * OutputStream.
585 */
586 protected Object replaceObject(Object obj) throws IOException {
587 return obj;
588 }
589
590 /**
591 * Enable the stream to do replacement of objects in the stream. When
592 * enabled, the replaceObject method is called for every object being
593 * serialized.
594 *
595 * <p>If <code>enable</code> is true, and there is a security manager
596 * installed, this method first calls the security manager's
597 * <code>checkPermission</code> method with a
598 * <code>SerializablePermission("enableSubstitution")</code> permission to
599 * ensure it's ok to enable the stream to do replacement of objects in the
600 * stream.
601 *
602 * @param enable boolean parameter to enable replacement of objects
603 * @return the previous setting before this method was invoked
604 * @throws SecurityException if a security manager exists and its
605 * <code>checkPermission</code> method denies enabling the stream
606 * to do replacement of objects in the stream.
607 * @see SecurityManager#checkPermission
608 * @see java.io.SerializablePermission
609 */
610 protected boolean enableReplaceObject(boolean enable)
611 throws SecurityException
612 {
613 if (enable == enableReplace) {
614 return enable;
615 }
616 if (enable) {
617 SecurityManager sm = System.getSecurityManager();
618 if (sm != null) {
619 sm.checkPermission(SUBSTITUTION_PERMISSION);
620 }
621 }
622 enableReplace = enable;
623 return !enableReplace;
624 }
625
626 /**
627 * The writeStreamHeader method is provided so subclasses can append or
628 * prepend their own header to the stream. It writes the magic number and
629 * version to the stream.
630 *
631 * @throws IOException if I/O errors occur while writing to the underlying
632 * stream
633 */
634 protected void writeStreamHeader() throws IOException {
635 bout.writeShort(STREAM_MAGIC);
636 bout.writeShort(STREAM_VERSION);
637 }
638
639 /**
640 * Write the specified class descriptor to the ObjectOutputStream. Class
641 * descriptors are used to identify the classes of objects written to the
642 * stream. Subclasses of ObjectOutputStream may override this method to
643 * customize the way in which class descriptors are written to the
644 * serialization stream. The corresponding method in ObjectInputStream,
645 * <code>readClassDescriptor</code>, should then be overridden to
646 * reconstitute the class descriptor from its custom stream representation.
647 * By default, this method writes class descriptors according to the format
648 * defined in the Object Serialization specification.
649 *
650 * <p>Note that this method will only be called if the ObjectOutputStream
651 * is not using the old serialization stream format (set by calling
652 * ObjectOutputStream's <code>useProtocolVersion</code> method). If this
653 * serialization stream is using the old format
654 * (<code>PROTOCOL_VERSION_1</code>), the class descriptor will be written
655 * internally in a manner that cannot be overridden or customized.
656 *
657 * @param desc class descriptor to write to the stream
658 * @throws IOException If an I/O error has occurred.
659 * @see java.io.ObjectInputStream#readClassDescriptor()
660 * @see #useProtocolVersion(int)
661 * @see java.io.ObjectStreamConstants#PROTOCOL_VERSION_1
662 * @since 1.3
663 */
664 protected void writeClassDescriptor(ObjectStreamClass desc)
665 throws IOException
666 {
667 desc.writeNonProxy(this);
668 }
669
670 /**
671 * Writes a byte. This method will block until the byte is actually
672 * written.
673 *
674 * @param val the byte to be written to the stream
675 * @throws IOException If an I/O error has occurred.
676 */
677 public void write(int val) throws IOException {
678 bout.write(val);
679 }
680
681 /**
682 * Writes an array of bytes. This method will block until the bytes are
683 * actually written.
684 *
685 * @param buf the data to be written
686 * @throws IOException If an I/O error has occurred.
687 */
688 public void write(byte[] buf) throws IOException {
689 bout.write(buf, 0, buf.length, false);
690 }
691
692 /**
693 * Writes a sub array of bytes.
694 *
695 * @param buf the data to be written
696 * @param off the start offset in the data
697 * @param len the number of bytes that are written
698 * @throws IOException If an I/O error has occurred.
699 */
700 public void write(byte[] buf, int off, int len) throws IOException {
701 if (buf == null) {
702 throw new NullPointerException();
703 }
704 int endoff = off + len;
705 if (off < 0 || len < 0 || endoff > buf.length || endoff < 0) {
706 throw new IndexOutOfBoundsException();
707 }
708 bout.write(buf, off, len, false);
709 }
710
711 /**
712 * Flushes the stream. This will write any buffered output bytes and flush
713 * through to the underlying stream.
714 *
715 * @throws IOException If an I/O error has occurred.
716 */
717 public void flush() throws IOException {
718 bout.flush();
719 }
720
721 /**
722 * Drain any buffered data in ObjectOutputStream. Similar to flush but
723 * does not propagate the flush to the underlying stream.
724 *
725 * @throws IOException if I/O errors occur while writing to the underlying
726 * stream
727 */
728 protected void drain() throws IOException {
729 bout.drain();
730 }
731
732 /**
733 * Closes the stream. This method must be called to release any resources
734 * associated with the stream.
735 *
736 * @throws IOException If an I/O error has occurred.
737 */
738 public void close() throws IOException {
739 flush();
740 clear();
741 bout.close();
742 }
743
744 /**
745 * Writes a boolean.
746 *
747 * @param val the boolean to be written
748 * @throws IOException if I/O errors occur while writing to the underlying
749 * stream
750 */
751 public void writeBoolean(boolean val) throws IOException {
752 bout.writeBoolean(val);
753 }
754
755 /**
756 * Writes an 8 bit byte.
757 *
758 * @param val the byte value to be written
759 * @throws IOException if I/O errors occur while writing to the underlying
760 * stream
761 */
762 public void writeByte(int val) throws IOException {
763 bout.writeByte(val);
764 }
765
766 /**
767 * Writes a 16 bit short.
768 *
769 * @param val the short value to be written
770 * @throws IOException if I/O errors occur while writing to the underlying
771 * stream
772 */
773 public void writeShort(int val) throws IOException {
774 bout.writeShort(val);
775 }
776
777 /**
778 * Writes a 16 bit char.
779 *
780 * @param val the char value to be written
781 * @throws IOException if I/O errors occur while writing to the underlying
782 * stream
783 */
784 public void writeChar(int val) throws IOException {
785 bout.writeChar(val);
786 }
787
788 /**
789 * Writes a 32 bit int.
790 *
791 * @param val the integer value to be written
792 * @throws IOException if I/O errors occur while writing to the underlying
793 * stream
794 */
795 public void writeInt(int val) throws IOException {
796 bout.writeInt(val);
797 }
798
799 /**
800 * Writes a 64 bit long.
801 *
802 * @param val the long value to be written
803 * @throws IOException if I/O errors occur while writing to the underlying
804 * stream
805 */
806 public void writeLong(long val) throws IOException {
807 bout.writeLong(val);
808 }
809
810 /**
811 * Writes a 32 bit float.
812 *
813 * @param val the float value to be written
814 * @throws IOException if I/O errors occur while writing to the underlying
815 * stream
816 */
817 public void writeFloat(float val) throws IOException {
818 bout.writeFloat(val);
819 }
820
821 /**
822 * Writes a 64 bit double.
823 *
824 * @param val the double value to be written
825 * @throws IOException if I/O errors occur while writing to the underlying
826 * stream
827 */
828 public void writeDouble(double val) throws IOException {
829 bout.writeDouble(val);
830 }
831
832 /**
833 * Writes a String as a sequence of bytes.
834 *
835 * @param str the String of bytes to be written
836 * @throws IOException if I/O errors occur while writing to the underlying
837 * stream
838 */
839 public void writeBytes(String str) throws IOException {
840 bout.writeBytes(str);
841 }
842
843 /**
844 * Writes a String as a sequence of chars.
845 *
846 * @param str the String of chars to be written
847 * @throws IOException if I/O errors occur while writing to the underlying
848 * stream
849 */
850 public void writeChars(String str) throws IOException {
851 bout.writeChars(str);
852 }
853
854 /**
855 * Primitive data write of this String in
856 * <a href="DataInput.html#modified-utf-8">modified UTF-8</a>
857 * format. Note that there is a
858 * significant difference between writing a String into the stream as
859 * primitive data or as an Object. A String instance written by writeObject
860 * is written into the stream as a String initially. Future writeObject()
861 * calls write references to the string into the stream.
862 *
863 * @param str the String to be written
864 * @throws IOException if I/O errors occur while writing to the underlying
865 * stream
866 */
867 public void writeUTF(String str) throws IOException {
868 bout.writeUTF(str);
869 }
870
871 /**
872 * Provide programmatic access to the persistent fields to be written
873 * to ObjectOutput.
874 *
875 * @since 1.2
876 */
877 public static abstract class PutField {
878
879 /**
880 * Put the value of the named boolean field into the persistent field.
881 *
882 * @param name the name of the serializable field
883 * @param val the value to assign to the field
884 * @throws IllegalArgumentException if <code>name</code> does not
885 * match the name of a serializable field for the class whose fields
886 * are being written, or if the type of the named field is not
887 * <code>boolean</code>
888 */
889 public abstract void put(String name, boolean val);
890
891 /**
892 * Put the value of the named byte field into the persistent field.
893 *
894 * @param name the name of the serializable field
895 * @param val the value to assign to the field
896 * @throws IllegalArgumentException if <code>name</code> does not
897 * match the name of a serializable field for the class whose fields
898 * are being written, or if the type of the named field is not
899 * <code>byte</code>
900 */
901 public abstract void put(String name, byte val);
902
903 /**
904 * Put the value of the named char field into the persistent field.
905 *
906 * @param name the name of the serializable field
907 * @param val the value to assign to the field
908 * @throws IllegalArgumentException if <code>name</code> does not
909 * match the name of a serializable field for the class whose fields
910 * are being written, or if the type of the named field is not
911 * <code>char</code>
912 */
913 public abstract void put(String name, char val);
914
915 /**
916 * Put the value of the named short field into the persistent field.
917 *
918 * @param name the name of the serializable field
919 * @param val the value to assign to the field
920 * @throws IllegalArgumentException if <code>name</code> does not
921 * match the name of a serializable field for the class whose fields
922 * are being written, or if the type of the named field is not
923 * <code>short</code>
924 */
925 public abstract void put(String name, short val);
926
927 /**
928 * Put the value of the named int field into the persistent field.
929 *
930 * @param name the name of the serializable field
931 * @param val the value to assign to the field
932 * @throws IllegalArgumentException if <code>name</code> does not
933 * match the name of a serializable field for the class whose fields
934 * are being written, or if the type of the named field is not
935 * <code>int</code>
936 */
937 public abstract void put(String name, int val);
938
939 /**
940 * Put the value of the named long field into the persistent field.
941 *
942 * @param name the name of the serializable field
943 * @param val the value to assign to the field
944 * @throws IllegalArgumentException if <code>name</code> does not
945 * match the name of a serializable field for the class whose fields
946 * are being written, or if the type of the named field is not
947 * <code>long</code>
948 */
949 public abstract void put(String name, long val);
950
951 /**
952 * Put the value of the named float field into the persistent field.
953 *
954 * @param name the name of the serializable field
955 * @param val the value to assign to the field
956 * @throws IllegalArgumentException if <code>name</code> does not
957 * match the name of a serializable field for the class whose fields
958 * are being written, or if the type of the named field is not
959 * <code>float</code>
960 */
961 public abstract void put(String name, float val);
962
963 /**
964 * Put the value of the named double field into the persistent field.
965 *
966 * @param name the name of the serializable field
967 * @param val the value to assign to the field
968 * @throws IllegalArgumentException if <code>name</code> does not
969 * match the name of a serializable field for the class whose fields
970 * are being written, or if the type of the named field is not
971 * <code>double</code>
972 */
973 public abstract void put(String name, double val);
974
975 /**
976 * Put the value of the named Object field into the persistent field.
977 *
978 * @param name the name of the serializable field
979 * @param val the value to assign to the field
980 * (which may be <code>null</code>)
981 * @throws IllegalArgumentException if <code>name</code> does not
982 * match the name of a serializable field for the class whose fields
983 * are being written, or if the type of the named field is not a
984 * reference type
985 */
986 public abstract void put(String name, Object val);
987
988 /**
989 * Write the data and fields to the specified ObjectOutput stream,
990 * which must be the same stream that produced this
991 * <code>PutField</code> object.
992 *
993 * @param out the stream to write the data and fields to
994 * @throws IOException if I/O errors occur while writing to the
995 * underlying stream
996 * @throws IllegalArgumentException if the specified stream is not
997 * the same stream that produced this <code>PutField</code>
998 * object
999 * @deprecated This method does not write the values contained by this
1000 * <code>PutField</code> object in a proper format, and may
1001 * result in corruption of the serialization stream. The
1002 * correct way to write <code>PutField</code> data is by
1003 * calling the {@link java.io.ObjectOutputStream#writeFields()}
1004 * method.
1005 */
1006 @Deprecated
1007 public abstract void write(ObjectOutput out) throws IOException;
1008 }
1009
1010
1011 /**
1012 * Returns protocol version in use.
1013 */
1014 int getProtocolVersion() {
1015 return protocol;
1016 }
1017
1018 /**
1019 * Writes string without allowing it to be replaced in stream. Used by
1020 * ObjectStreamClass to write class descriptor type strings.
1021 */
1022 void writeTypeString(String str) throws IOException {
1023 int handle;
1024 if (str == null) {
1025 writeNull();
1026 } else if ((handle = handles.lookup(str)) != -1) {
1027 writeHandle(handle);
1028 } else {
1029 writeString(str, false);
1030 }
1031 }
1032
1033 /**
1034 * Verifies that this (possibly subclass) instance can be constructed
1035 * without violating security constraints: the subclass must not override
1036 * security-sensitive non-final methods, or else the
1037 * "enableSubclassImplementation" SerializablePermission is checked.
1038 */
1039 private void verifySubclass() {
1040 Class<?> cl = getClass();
1041 if (cl == ObjectOutputStream.class) {
1042 return;
1043 }
1044 SecurityManager sm = System.getSecurityManager();
1045 if (sm == null) {
1046 return;
1047 }
1048 processQueue(Caches.subclassAuditsQueue, Caches.subclassAudits);
1049 WeakClassKey key = new WeakClassKey(cl, Caches.subclassAuditsQueue);
1050 Boolean result = Caches.subclassAudits.get(key);
1051 if (result == null) {
1052 result = Boolean.valueOf(auditSubclass(cl));
1053 Caches.subclassAudits.putIfAbsent(key, result);
1054 }
1055 if (result.booleanValue()) {
1056 return;
1057 }
1058 sm.checkPermission(SUBCLASS_IMPLEMENTATION_PERMISSION);
1059 }
1060
1061 /**
1062 * Performs reflective checks on given subclass to verify that it doesn't
1063 * override security-sensitive non-final methods. Returns true if subclass
1064 * is "safe", false otherwise.
1065 */
1066 private static boolean auditSubclass(final Class<?> subcl) {
1067 Boolean result = AccessController.doPrivileged(
1068 new PrivilegedAction<Boolean>() {
1069 public Boolean run() {
1070 for (Class<?> cl = subcl;
1071 cl != ObjectOutputStream.class;
1072 cl = cl.getSuperclass())
1073 {
1074 try {
1075 cl.getDeclaredMethod(
1076 "writeUnshared", new Class<?>[] { Object.class });
1077 return Boolean.FALSE;
1078 } catch (NoSuchMethodException ex) {
1079 }
1080 try {
1081 cl.getDeclaredMethod("putFields", (Class<?>[]) null);
1082 return Boolean.FALSE;
1083 } catch (NoSuchMethodException ex) {
1084 }
1085 }
1086 return Boolean.TRUE;
1087 }
1088 }
1089 );
1090 return result.booleanValue();
1091 }
1092
1093 /**
1094 * Clears internal data structures.
1095 */
1096 private void clear() {
1097 subs.clear();
1098 handles.clear();
1099 }
1100
1101 /**
1102 * Underlying writeObject/writeUnshared implementation.
1103 */
1104 private void writeObject0(Object obj, boolean unshared)
1105 throws IOException
1106 {
1107 boolean oldMode = bout.setBlockDataMode(false);
1108 depth++;
1109 try {
1110 // handle previously written and non-replaceable objects
1111 int h;
1112 if ((obj = subs.lookup(obj)) == null) {
1113 writeNull();
1114 return;
1115 } else if (!unshared && (h = handles.lookup(obj)) != -1) {
1116 writeHandle(h);
1117 return;
1118 } else if (obj instanceof Class) {
1119 writeClass((Class) obj, unshared);
1120 return;
1121 } else if (obj instanceof ObjectStreamClass) {
1122 writeClassDesc((ObjectStreamClass) obj, unshared);
1123 return;
1124 }
1125
1126 // check for replacement object
1127 Object orig = obj;
1128 Class<?> cl = obj.getClass();
1129 ObjectStreamClass desc;
1130 for (;;) {
1131 // REMIND: skip this check for strings/arrays?
1132 Class<?> repCl;
1133 desc = ObjectStreamClass.lookup(cl, true);
1134 if (!desc.hasWriteReplaceMethod() ||
1135 (obj = desc.invokeWriteReplace(obj)) == null ||
1136 (repCl = obj.getClass()) == cl)
1137 {
1138 break;
1139 }
1140 cl = repCl;
1141 }
1142 if (enableReplace) {
1143 Object rep = replaceObject(obj);
1144 if (rep != obj && rep != null) {
1145 cl = rep.getClass();
1146 desc = ObjectStreamClass.lookup(cl, true);
1147 }
1148 obj = rep;
1149 }
1150
1151 // if object replaced, run through original checks a second time
1152 if (obj != orig) {
1153 subs.assign(orig, obj);
1154 if (obj == null) {
1155 writeNull();
1156 return;
1157 } else if (!unshared && (h = handles.lookup(obj)) != -1) {
1158 writeHandle(h);
1159 return;
1160 } else if (obj instanceof Class) {
1161 writeClass((Class) obj, unshared);
1162 return;
1163 } else if (obj instanceof ObjectStreamClass) {
1164 writeClassDesc((ObjectStreamClass) obj, unshared);
1165 return;
1166 }
1167 }
1168
1169 // remaining cases
1170 if (obj instanceof String) {
1171 writeString((String) obj, unshared);
1172 } else if (cl.isArray()) {
1173 writeArray(obj, desc, unshared);
1174 } else if (obj instanceof Enum) {
1175 writeEnum((Enum<?>) obj, desc, unshared);
1176 } else if (obj instanceof Serializable) {
1177 writeOrdinaryObject(obj, desc, unshared);
1178 } else {
1179 if (extendedDebugInfo) {
1180 throw new NotSerializableException(
1181 cl.getName() + "\n" + debugInfoStack.toString());
1182 } else {
1183 throw new NotSerializableException(cl.getName());
1184 }
1185 }
1186 } finally {
1187 depth--;
1188 bout.setBlockDataMode(oldMode);
1189 }
1190 }
1191
1192 /**
1193 * Writes null code to stream.
1194 */
1195 private void writeNull() throws IOException {
1196 bout.writeByte(TC_NULL);
1197 }
1198
1199 /**
1200 * Writes given object handle to stream.
1201 */
1202 private void writeHandle(int handle) throws IOException {
1203 bout.writeByte(TC_REFERENCE);
1204 bout.writeInt(baseWireHandle + handle);
1205 }
1206
1207 /**
1208 * Writes representation of given class to stream.
1209 */
1210 private void writeClass(Class<?> cl, boolean unshared) throws IOException {
1211 bout.writeByte(TC_CLASS);
1212 writeClassDesc(ObjectStreamClass.lookup(cl, true), false);
1213 handles.assign(unshared ? null : cl);
1214 }
1215
1216 /**
1217 * Writes representation of given class descriptor to stream.
1218 */
1219 private void writeClassDesc(ObjectStreamClass desc, boolean unshared)
1220 throws IOException
1221 {
1222 int handle;
1223 if (desc == null) {
1224 writeNull();
1225 } else if (!unshared && (handle = handles.lookup(desc)) != -1) {
1226 writeHandle(handle);
1227 } else if (desc.isProxy()) {
1228 writeProxyDesc(desc, unshared);
1229 } else {
1230 writeNonProxyDesc(desc, unshared);
1231 }
1232 }
1233
1234 private boolean isCustomSubclass() {
1235 // Return true if this class is a custom subclass of ObjectOutputStream
1236 return getClass().getClassLoader()
1237 != ObjectOutputStream.class.getClassLoader();
1238 }
1239
1240 /**
1241 * Writes class descriptor representing a dynamic proxy class to stream.
1242 */
1243 private void writeProxyDesc(ObjectStreamClass desc, boolean unshared)
1244 throws IOException
1245 {
1246 bout.writeByte(TC_PROXYCLASSDESC);
1247 handles.assign(unshared ? null : desc);
1248
1249 Class<?> cl = desc.forClass();
1250 Class<?>[] ifaces = cl.getInterfaces();
1251 bout.writeInt(ifaces.length);
1252 for (int i = 0; i < ifaces.length; i++) {
1253 bout.writeUTF(ifaces[i].getName());
1254 }
1255
1256 bout.setBlockDataMode(true);
1257 if (isCustomSubclass()) {
1258 ReflectUtil.checkPackageAccess(cl);
1259 }
1260 annotateProxyClass(cl);
1261 bout.setBlockDataMode(false);
1262 bout.writeByte(TC_ENDBLOCKDATA);
1263
1264 writeClassDesc(desc.getSuperDesc(), false);
1265 }
1266
1267 /**
1268 * Writes class descriptor representing a standard (i.e., not a dynamic
1269 * proxy) class to stream.
1270 */
1271 private void writeNonProxyDesc(ObjectStreamClass desc, boolean unshared)
1272 throws IOException
1273 {
1274 bout.writeByte(TC_CLASSDESC);
1275 handles.assign(unshared ? null : desc);
1276
1277 if (protocol == PROTOCOL_VERSION_1) {
1278 // do not invoke class descriptor write hook with old protocol
1279 desc.writeNonProxy(this);
1280 } else {
1281 writeClassDescriptor(desc);
1282 }
1283
1284 Class<?> cl = desc.forClass();
1285 bout.setBlockDataMode(true);
1286 if (isCustomSubclass()) {
1287 ReflectUtil.checkPackageAccess(cl);
1288 }
1289 annotateClass(cl);
1290 bout.setBlockDataMode(false);
1291 bout.writeByte(TC_ENDBLOCKDATA);
1292
1293 writeClassDesc(desc.getSuperDesc(), false);
1294 }
1295
1296 /**
1297 * Writes given string to stream, using standard or long UTF format
1298 * depending on string length.
1299 */
1300 private void writeString(String str, boolean unshared) throws IOException {
1301 handles.assign(unshared ? null : str);
1302 long utflen = bout.getUTFLength(str);
1303 if (utflen <= 0xFFFF) {
1304 bout.writeByte(TC_STRING);
1305 bout.writeUTF(str, utflen);
1306 } else {
1307 bout.writeByte(TC_LONGSTRING);
1308 bout.writeLongUTF(str, utflen);
1309 }
1310 }
1311
1312 /**
1313 * Writes given array object to stream.
1314 */
1315 private void writeArray(Object array,
1316 ObjectStreamClass desc,
1317 boolean unshared)
1318 throws IOException
1319 {
1320 bout.writeByte(TC_ARRAY);
1321 writeClassDesc(desc, false);
1322 handles.assign(unshared ? null : array);
1323
1324 Class<?> ccl = desc.forClass().getComponentType();
1325 if (ccl.isPrimitive()) {
1326 if (ccl == Integer.TYPE) {
1327 int[] ia = (int[]) array;
1328 bout.writeInt(ia.length);
1329 bout.writeInts(ia, 0, ia.length);
1330 } else if (ccl == Byte.TYPE) {
1331 byte[] ba = (byte[]) array;
1332 bout.writeInt(ba.length);
1333 bout.write(ba, 0, ba.length, true);
1334 } else if (ccl == Long.TYPE) {
1335 long[] ja = (long[]) array;
1336 bout.writeInt(ja.length);
1337 bout.writeLongs(ja, 0, ja.length);
1338 } else if (ccl == Float.TYPE) {
1339 float[] fa = (float[]) array;
1340 bout.writeInt(fa.length);
1341 bout.writeFloats(fa, 0, fa.length);
1342 } else if (ccl == Double.TYPE) {
1343 double[] da = (double[]) array;
1344 bout.writeInt(da.length);
1345 bout.writeDoubles(da, 0, da.length);
1346 } else if (ccl == Short.TYPE) {
1347 short[] sa = (short[]) array;
1348 bout.writeInt(sa.length);
1349 bout.writeShorts(sa, 0, sa.length);
1350 } else if (ccl == Character.TYPE) {
1351 char[] ca = (char[]) array;
1352 bout.writeInt(ca.length);
1353 bout.writeChars(ca, 0, ca.length);
1354 } else if (ccl == Boolean.TYPE) {
1355 boolean[] za = (boolean[]) array;
1356 bout.writeInt(za.length);
1357 bout.writeBooleans(za, 0, za.length);
1358 } else {
1359 throw new InternalError();
1360 }
1361 } else {
1362 Object[] objs = (Object[]) array;
1363 int len = objs.length;
1364 bout.writeInt(len);
1365 if (extendedDebugInfo) {
1366 debugInfoStack.push(
1367 "array (class \"" + array.getClass().getName() +
1368 "\", size: " + len + ")");
1369 }
1370 try {
1371 for (int i = 0; i < len; i++) {
1372 if (extendedDebugInfo) {
1373 debugInfoStack.push(
1374 "element of array (index: " + i + ")");
1375 }
1376 try {
1377 writeObject0(objs[i], false);
1378 } finally {
1379 if (extendedDebugInfo) {
1380 debugInfoStack.pop();
1381 }
1382 }
1383 }
1384 } finally {
1385 if (extendedDebugInfo) {
1386 debugInfoStack.pop();
1387 }
1388 }
1389 }
1390 }
1391
1392 /**
1393 * Writes given enum constant to stream.
1394 */
1395 private void writeEnum(Enum<?> en,
1396 ObjectStreamClass desc,
1397 boolean unshared)
1398 throws IOException
1399 {
1400 bout.writeByte(TC_ENUM);
1401 ObjectStreamClass sdesc = desc.getSuperDesc();
1402 writeClassDesc((sdesc.forClass() == Enum.class) ? desc : sdesc, false);
1403 handles.assign(unshared ? null : en);
1404 writeString(en.name(), false);
1405 }
1406
1407 /**
1408 * Writes representation of a "ordinary" (i.e., not a String, Class,
1409 * ObjectStreamClass, array, or enum constant) serializable object to the
1410 * stream.
1411 */
1412 private void writeOrdinaryObject(Object obj,
1413 ObjectStreamClass desc,
1414 boolean unshared)
1415 throws IOException
1416 {
1417 if (extendedDebugInfo) {
1418 debugInfoStack.push(
1419 (depth == 1 ? "root " : "") + "object (class \"" +
1420 obj.getClass().getName() + "\", " + obj.toString() + ")");
1421 }
1422 try {
1423 desc.checkSerialize();
1424
1425 bout.writeByte(TC_OBJECT);
1426 writeClassDesc(desc, false);
1427 handles.assign(unshared ? null : obj);
1428 if (desc.isExternalizable() && !desc.isProxy()) {
1429 writeExternalData((Externalizable) obj);
1430 } else {
1431 writeSerialData(obj, desc);
1432 }
1433 } finally {
1434 if (extendedDebugInfo) {
1435 debugInfoStack.pop();
1436 }
1437 }
1438 }
1439
1440 /**
1441 * Writes externalizable data of given object by invoking its
1442 * writeExternal() method.
1443 */
1444 private void writeExternalData(Externalizable obj) throws IOException {
1445 PutFieldImpl oldPut = curPut;
1446 curPut = null;
1447
1448 if (extendedDebugInfo) {
1449 debugInfoStack.push("writeExternal data");
1450 }
1451 SerialCallbackContext oldContext = curContext;
1452 try {
1453 curContext = null;
1454 if (protocol == PROTOCOL_VERSION_1) {
1455 obj.writeExternal(this);
1456 } else {
1457 bout.setBlockDataMode(true);
1458 obj.writeExternal(this);
1459 bout.setBlockDataMode(false);
1460 bout.writeByte(TC_ENDBLOCKDATA);
1461 }
1462 } finally {
1463 curContext = oldContext;
1464 if (extendedDebugInfo) {
1465 debugInfoStack.pop();
1466 }
1467 }
1468
1469 curPut = oldPut;
1470 }
1471
1472 /**
1473 * Writes instance data for each serializable class of given object, from
1474 * superclass to subclass.
1475 */
1476 private void writeSerialData(Object obj, ObjectStreamClass desc)
1477 throws IOException
1478 {
1479 ObjectStreamClass.ClassDataSlot[] slots = desc.getClassDataLayout();
1480 for (int i = 0; i < slots.length; i++) {
1481 ObjectStreamClass slotDesc = slots[i].desc;
1482 if (slotDesc.hasWriteObjectMethod()) {
1483 PutFieldImpl oldPut = curPut;
1484 curPut = null;
1485 SerialCallbackContext oldContext = curContext;
1486
1487 if (extendedDebugInfo) {
1488 debugInfoStack.push(
1489 "custom writeObject data (class \"" +
1490 slotDesc.getName() + "\")");
1491 }
1492 try {
1493 curContext = new SerialCallbackContext(obj, slotDesc);
1494 bout.setBlockDataMode(true);
1495 slotDesc.invokeWriteObject(obj, this);
1496 bout.setBlockDataMode(false);
1497 bout.writeByte(TC_ENDBLOCKDATA);
1498 } finally {
1499 curContext.setUsed();
1500 curContext = oldContext;
1501 if (extendedDebugInfo) {
1502 debugInfoStack.pop();
1503 }
1504 }
1505
1506 curPut = oldPut;
1507 } else {
1508 defaultWriteFields(obj, slotDesc);
1509 }
1510 }
1511 }
1512
1513 /**
1514 * Fetches and writes values of serializable fields of given object to
1515 * stream. The given class descriptor specifies which field values to
1516 * write, and in which order they should be written.
1517 */
1518 private void defaultWriteFields(Object obj, ObjectStreamClass desc)
1519 throws IOException
1520 {
1521 Class<?> cl = desc.forClass();
1522 if (cl != null && obj != null && !cl.isInstance(obj)) {
1523 throw new ClassCastException();
1524 }
1525
1526 desc.checkDefaultSerialize();
1527
1528 int primDataSize = desc.getPrimDataSize();
1529 if (primDataSize > 0) {
1530 if (primVals == null || primVals.length < primDataSize) {
1531 primVals = new byte[primDataSize];
1532 }
1533 desc.getPrimFieldValues(obj, primVals);
1534 bout.write(primVals, 0, primDataSize, false);
1535 }
1536
1537 int numObjFields = desc.getNumObjFields();
1538 if (numObjFields > 0) {
1539 ObjectStreamField[] fields = desc.getFields(false);
1540 Object[] objVals = new Object[numObjFields];
1541 int numPrimFields = fields.length - objVals.length;
1542 desc.getObjFieldValues(obj, objVals);
1543 for (int i = 0; i < objVals.length; i++) {
1544 if (extendedDebugInfo) {
1545 debugInfoStack.push(
1546 "field (class \"" + desc.getName() + "\", name: \"" +
1547 fields[numPrimFields + i].getName() + "\", type: \"" +
1548 fields[numPrimFields + i].getType() + "\")");
1549 }
1550 try {
1551 writeObject0(objVals[i],
1552 fields[numPrimFields + i].isUnshared());
1553 } finally {
1554 if (extendedDebugInfo) {
1555 debugInfoStack.pop();
1556 }
1557 }
1558 }
1559 }
1560 }
1561
1562 /**
1563 * Attempts to write to stream fatal IOException that has caused
1564 * serialization to abort.
1565 */
1566 private void writeFatalException(IOException ex) throws IOException {
1567 /*
1568 * Note: the serialization specification states that if a second
1569 * IOException occurs while attempting to serialize the original fatal
1570 * exception to the stream, then a StreamCorruptedException should be
1571 * thrown (section 2.1). However, due to a bug in previous
1572 * implementations of serialization, StreamCorruptedExceptions were
1573 * rarely (if ever) actually thrown--the "root" exceptions from
1574 * underlying streams were thrown instead. This historical behavior is
1575 * followed here for consistency.
1576 */
1577 clear();
1578 boolean oldMode = bout.setBlockDataMode(false);
1579 try {
1580 bout.writeByte(TC_EXCEPTION);
1581 writeObject0(ex, false);
1582 clear();
1583 } finally {
1584 bout.setBlockDataMode(oldMode);
1585 }
1586 }
1587
1588 /**
1589 * Converts specified span of float values into byte values.
1590 */
1591 // REMIND: remove once hotspot inlines Float.floatToIntBits
1592 private static native void floatsToBytes(float[] src, int srcpos,
1593 byte[] dst, int dstpos,
1594 int nfloats);
1595
1596 /**
1597 * Converts specified span of double values into byte values.
1598 */
1599 // REMIND: remove once hotspot inlines Double.doubleToLongBits
1600 private static native void doublesToBytes(double[] src, int srcpos,
1601 byte[] dst, int dstpos,
1602 int ndoubles);
1603
1604 /**
1605 * Default PutField implementation.
1606 */
1607 private class PutFieldImpl extends PutField {
1608
1609 /** class descriptor describing serializable fields */
1610 private final ObjectStreamClass desc;
1611 /** primitive field values */
1612 private final byte[] primVals;
1613 /** object field values */
1614 private final Object[] objVals;
1615
1616 /**
1617 * Creates PutFieldImpl object for writing fields defined in given
1618 * class descriptor.
1619 */
1620 PutFieldImpl(ObjectStreamClass desc) {
1621 this.desc = desc;
1622 primVals = new byte[desc.getPrimDataSize()];
1623 objVals = new Object[desc.getNumObjFields()];
1624 }
1625
1626 public void put(String name, boolean val) {
1627 Bits.putBoolean(primVals, getFieldOffset(name, Boolean.TYPE), val);
1628 }
1629
1630 public void put(String name, byte val) {
1631 primVals[getFieldOffset(name, Byte.TYPE)] = val;
1632 }
1633
1634 public void put(String name, char val) {
1635 Bits.putChar(primVals, getFieldOffset(name, Character.TYPE), val);
1636 }
1637
1638 public void put(String name, short val) {
1639 Bits.putShort(primVals, getFieldOffset(name, Short.TYPE), val);
1640 }
1641
1642 public void put(String name, int val) {
1643 Bits.putInt(primVals, getFieldOffset(name, Integer.TYPE), val);
1644 }
1645
1646 public void put(String name, float val) {
1647 Bits.putFloat(primVals, getFieldOffset(name, Float.TYPE), val);
1648 }
1649
1650 public void put(String name, long val) {
1651 Bits.putLong(primVals, getFieldOffset(name, Long.TYPE), val);
1652 }
1653
1654 public void put(String name, double val) {
1655 Bits.putDouble(primVals, getFieldOffset(name, Double.TYPE), val);
1656 }
1657
1658 public void put(String name, Object val) {
1659 objVals[getFieldOffset(name, Object.class)] = val;
1660 }
1661
1662 // deprecated in ObjectOutputStream.PutField
1663 public void write(ObjectOutput out) throws IOException {
1664 /*
1665 * Applications should *not* use this method to write PutField
1666 * data, as it will lead to stream corruption if the PutField
1667 * object writes any primitive data (since block data mode is not
1668 * unset/set properly, as is done in OOS.writeFields()). This
1669 * broken implementation is being retained solely for behavioral
1670 * compatibility, in order to support applications which use
1671 * OOS.PutField.write() for writing only non-primitive data.
1672 *
1673 * Serialization of unshared objects is not implemented here since
1674 * it is not necessary for backwards compatibility; also, unshared
1675 * semantics may not be supported by the given ObjectOutput
1676 * instance. Applications which write unshared objects using the
1677 * PutField API must use OOS.writeFields().
1678 */
1679 if (ObjectOutputStream.this != out) {
1680 throw new IllegalArgumentException("wrong stream");
1681 }
1682 out.write(primVals, 0, primVals.length);
1683
1684 ObjectStreamField[] fields = desc.getFields(false);
1685 int numPrimFields = fields.length - objVals.length;
1686 // REMIND: warn if numPrimFields > 0?
1687 for (int i = 0; i < objVals.length; i++) {
1688 if (fields[numPrimFields + i].isUnshared()) {
1689 throw new IOException("cannot write unshared object");
1690 }
1691 out.writeObject(objVals[i]);
1692 }
1693 }
1694
1695 /**
1696 * Writes buffered primitive data and object fields to stream.
1697 */
1698 void writeFields() throws IOException {
1699 bout.write(primVals, 0, primVals.length, false);
1700
1701 ObjectStreamField[] fields = desc.getFields(false);
1702 int numPrimFields = fields.length - objVals.length;
1703 for (int i = 0; i < objVals.length; i++) {
1704 if (extendedDebugInfo) {
1705 debugInfoStack.push(
1706 "field (class \"" + desc.getName() + "\", name: \"" +
1707 fields[numPrimFields + i].getName() + "\", type: \"" +
1708 fields[numPrimFields + i].getType() + "\")");
1709 }
1710 try {
1711 writeObject0(objVals[i],
1712 fields[numPrimFields + i].isUnshared());
1713 } finally {
1714 if (extendedDebugInfo) {
1715 debugInfoStack.pop();
1716 }
1717 }
1718 }
1719 }
1720
1721 /**
1722 * Returns offset of field with given name and type. A specified type
1723 * of null matches all types, Object.class matches all non-primitive
1724 * types, and any other non-null type matches assignable types only.
1725 * Throws IllegalArgumentException if no matching field found.
1726 */
1727 private int getFieldOffset(String name, Class<?> type) {
1728 ObjectStreamField field = desc.getField(name, type);
1729 if (field == null) {
1730 throw new IllegalArgumentException("no such field " + name +
1731 " with type " + type);
1732 }
1733 return field.getOffset();
1734 }
1735 }
1736
1737 /**
1738 * Buffered output stream with two modes: in default mode, outputs data in
1739 * same format as DataOutputStream; in "block data" mode, outputs data
1740 * bracketed by block data markers (see object serialization specification
1741 * for details).
1742 */
1743 private static class BlockDataOutputStream
1744 extends OutputStream implements DataOutput
1745 {
1746 /** maximum data block length */
1747 private static final int MAX_BLOCK_SIZE = 1024;
1748 /** maximum data block header length */
1749 private static final int MAX_HEADER_SIZE = 5;
1750 /** (tunable) length of char buffer (for writing strings) */
1751 private static final int CHAR_BUF_SIZE = 256;
1752
1753 /** buffer for writing general/block data */
1754 private final byte[] buf = new byte[MAX_BLOCK_SIZE];
1755 /** buffer for writing block data headers */
1756 private final byte[] hbuf = new byte[MAX_HEADER_SIZE];
1757 /** char buffer for fast string writes */
1758 private final char[] cbuf = new char[CHAR_BUF_SIZE];
1759
1760 /** block data mode */
1761 private boolean blkmode = false;
1762 /** current offset into buf */
1763 private int pos = 0;
1764
1765 /** underlying output stream */
1766 private final OutputStream out;
1767 /** loopback stream (for data writes that span data blocks) */
1768 private final DataOutputStream dout;
1769
1770 /**
1771 * Creates new BlockDataOutputStream on top of given underlying stream.
1772 * Block data mode is turned off by default.
1773 */
1774 BlockDataOutputStream(OutputStream out) {
1775 this.out = out;
1776 dout = new DataOutputStream(this);
1777 }
1778
1779 /**
1780 * Sets block data mode to the given mode (true == on, false == off)
1781 * and returns the previous mode value. If the new mode is the same as
1782 * the old mode, no action is taken. If the new mode differs from the
1783 * old mode, any buffered data is flushed before switching to the new
1784 * mode.
1785 */
1786 boolean setBlockDataMode(boolean mode) throws IOException {
1787 if (blkmode == mode) {
1788 return blkmode;
1789 }
1790 drain();
1791 blkmode = mode;
1792 return !blkmode;
1793 }
1794
1795 /**
1796 * Returns true if the stream is currently in block data mode, false
1797 * otherwise.
1798 */
1799 boolean getBlockDataMode() {
1800 return blkmode;
1801 }
1802
1803 /* ----------------- generic output stream methods ----------------- */
1804 /*
1805 * The following methods are equivalent to their counterparts in
1806 * OutputStream, except that they partition written data into data
1807 * blocks when in block data mode.
1808 */
1809
1810 public void write(int b) throws IOException {
1811 if (pos >= MAX_BLOCK_SIZE) {
1812 drain();
1813 }
1814 buf[pos++] = (byte) b;
1815 }
1816
1817 public void write(byte[] b) throws IOException {
1818 write(b, 0, b.length, false);
1819 }
1820
1821 public void write(byte[] b, int off, int len) throws IOException {
1822 write(b, off, len, false);
1823 }
1824
1825 public void flush() throws IOException {
1826 drain();
1827 out.flush();
1828 }
1829
1830 public void close() throws IOException {
1831 flush();
1832 out.close();
1833 }
1834
1835 /**
1836 * Writes specified span of byte values from given array. If copy is
1837 * true, copies the values to an intermediate buffer before writing
1838 * them to underlying stream (to avoid exposing a reference to the
1839 * original byte array).
1840 */
1841 void write(byte[] b, int off, int len, boolean copy)
1842 throws IOException
1843 {
1844 if (!(copy || blkmode)) { // write directly
1845 drain();
1846 out.write(b, off, len);
1847 return;
1848 }
1849
1850 while (len > 0) {
1851 if (pos >= MAX_BLOCK_SIZE) {
1852 drain();
1853 }
1854 if (len >= MAX_BLOCK_SIZE && !copy && pos == 0) {
1855 // avoid unnecessary copy
1856 writeBlockHeader(MAX_BLOCK_SIZE);
1857 out.write(b, off, MAX_BLOCK_SIZE);
1858 off += MAX_BLOCK_SIZE;
1859 len -= MAX_BLOCK_SIZE;
1860 } else {
1861 int wlen = Math.min(len, MAX_BLOCK_SIZE - pos);
1862 System.arraycopy(b, off, buf, pos, wlen);
1863 pos += wlen;
1864 off += wlen;
1865 len -= wlen;
1866 }
1867 }
1868 }
1869
1870 /**
1871 * Writes all buffered data from this stream to the underlying stream,
1872 * but does not flush underlying stream.
1873 */
1874 void drain() throws IOException {
1875 if (pos == 0) {
1876 return;
1877 }
1878 if (blkmode) {
1879 writeBlockHeader(pos);
1880 }
1881 out.write(buf, 0, pos);
1882 pos = 0;
1883 }
1884
1885 /**
1886 * Writes block data header. Data blocks shorter than 256 bytes are
1887 * prefixed with a 2-byte header; all others start with a 5-byte
1888 * header.
1889 */
1890 private void writeBlockHeader(int len) throws IOException {
1891 if (len <= 0xFF) {
1892 hbuf[0] = TC_BLOCKDATA;
1893 hbuf[1] = (byte) len;
1894 out.write(hbuf, 0, 2);
1895 } else {
1896 hbuf[0] = TC_BLOCKDATALONG;
1897 Bits.putInt(hbuf, 1, len);
1898 out.write(hbuf, 0, 5);
1899 }
1900 }
1901
1902
1903 /* ----------------- primitive data output methods ----------------- */
1904 /*
1905 * The following methods are equivalent to their counterparts in
1906 * DataOutputStream, except that they partition written data into data
1907 * blocks when in block data mode.
1908 */
1909
1910 public void writeBoolean(boolean v) throws IOException {
1911 if (pos >= MAX_BLOCK_SIZE) {
1912 drain();
1913 }
1914 Bits.putBoolean(buf, pos++, v);
1915 }
1916
1917 public void writeByte(int v) throws IOException {
1918 if (pos >= MAX_BLOCK_SIZE) {
1919 drain();
1920 }
1921 buf[pos++] = (byte) v;
1922 }
1923
1924 public void writeChar(int v) throws IOException {
1925 if (pos + 2 <= MAX_BLOCK_SIZE) {
1926 Bits.putChar(buf, pos, (char) v);
1927 pos += 2;
1928 } else {
1929 dout.writeChar(v);
1930 }
1931 }
1932
1933 public void writeShort(int v) throws IOException {
1934 if (pos + 2 <= MAX_BLOCK_SIZE) {
1935 Bits.putShort(buf, pos, (short) v);
1936 pos += 2;
1937 } else {
1938 dout.writeShort(v);
1939 }
1940 }
1941
1942 public void writeInt(int v) throws IOException {
1943 if (pos + 4 <= MAX_BLOCK_SIZE) {
1944 Bits.putInt(buf, pos, v);
1945 pos += 4;
1946 } else {
1947 dout.writeInt(v);
1948 }
1949 }
1950
1951 public void writeFloat(float v) throws IOException {
1952 if (pos + 4 <= MAX_BLOCK_SIZE) {
1953 Bits.putFloat(buf, pos, v);
1954 pos += 4;
1955 } else {
1956 dout.writeFloat(v);
1957 }
1958 }
1959
1960 public void writeLong(long v) throws IOException {
1961 if (pos + 8 <= MAX_BLOCK_SIZE) {
1962 Bits.putLong(buf, pos, v);
1963 pos += 8;
1964 } else {
1965 dout.writeLong(v);
1966 }
1967 }
1968
1969 public void writeDouble(double v) throws IOException {
1970 if (pos + 8 <= MAX_BLOCK_SIZE) {
1971 Bits.putDouble(buf, pos, v);
1972 pos += 8;
1973 } else {
1974 dout.writeDouble(v);
1975 }
1976 }
1977
1978 public void writeBytes(String s) throws IOException {
1979 int endoff = s.length();
1980 int cpos = 0;
1981 int csize = 0;
1982 for (int off = 0; off < endoff; ) {
1983 if (cpos >= csize) {
1984 cpos = 0;
1985 csize = Math.min(endoff - off, CHAR_BUF_SIZE);
1986 s.getChars(off, off + csize, cbuf, 0);
1987 }
1988 if (pos >= MAX_BLOCK_SIZE) {
1989 drain();
1990 }
1991 int n = Math.min(csize - cpos, MAX_BLOCK_SIZE - pos);
1992 int stop = pos + n;
1993 while (pos < stop) {
1994 buf[pos++] = (byte) cbuf[cpos++];
1995 }
1996 off += n;
1997 }
1998 }
1999
2000 public void writeChars(String s) throws IOException {
2001 int endoff = s.length();
2002 for (int off = 0; off < endoff; ) {
2003 int csize = Math.min(endoff - off, CHAR_BUF_SIZE);
2004 s.getChars(off, off + csize, cbuf, 0);
2005 writeChars(cbuf, 0, csize);
2006 off += csize;
2007 }
2008 }
2009
2010 public void writeUTF(String s) throws IOException {
2011 writeUTF(s, getUTFLength(s));
2012 }
2013
2014
2015 /* -------------- primitive data array output methods -------------- */
2016 /*
2017 * The following methods write out spans of primitive data values.
2018 * Though equivalent to calling the corresponding primitive write
2019 * methods repeatedly, these methods are optimized for writing groups
2020 * of primitive data values more efficiently.
2021 */
2022
2023 void writeBooleans(boolean[] v, int off, int len) throws IOException {
2024 int endoff = off + len;
2025 while (off < endoff) {
2026 if (pos >= MAX_BLOCK_SIZE) {
2027 drain();
2028 }
2029 int stop = Math.min(endoff, off + (MAX_BLOCK_SIZE - pos));
2030 while (off < stop) {
2031 Bits.putBoolean(buf, pos++, v[off++]);
2032 }
2033 }
2034 }
2035
2036 void writeChars(char[] v, int off, int len) throws IOException {
2037 int limit = MAX_BLOCK_SIZE - 2;
2038 int endoff = off + len;
2039 while (off < endoff) {
2040 if (pos <= limit) {
2041 int avail = (MAX_BLOCK_SIZE - pos) >> 1;
2042 int stop = Math.min(endoff, off + avail);
2043 while (off < stop) {
2044 Bits.putChar(buf, pos, v[off++]);
2045 pos += 2;
2046 }
2047 } else {
2048 dout.writeChar(v[off++]);
2049 }
2050 }
2051 }
2052
2053 void writeShorts(short[] v, int off, int len) throws IOException {
2054 int limit = MAX_BLOCK_SIZE - 2;
2055 int endoff = off + len;
2056 while (off < endoff) {
2057 if (pos <= limit) {
2058 int avail = (MAX_BLOCK_SIZE - pos) >> 1;
2059 int stop = Math.min(endoff, off + avail);
2060 while (off < stop) {
2061 Bits.putShort(buf, pos, v[off++]);
2062 pos += 2;
2063 }
2064 } else {
2065 dout.writeShort(v[off++]);
2066 }
2067 }
2068 }
2069
2070 void writeInts(int[] v, int off, int len) throws IOException {
2071 int limit = MAX_BLOCK_SIZE - 4;
2072 int endoff = off + len;
2073 while (off < endoff) {
2074 if (pos <= limit) {
2075 int avail = (MAX_BLOCK_SIZE - pos) >> 2;
2076 int stop = Math.min(endoff, off + avail);
2077 while (off < stop) {
2078 Bits.putInt(buf, pos, v[off++]);
2079 pos += 4;
2080 }
2081 } else {
2082 dout.writeInt(v[off++]);
2083 }
2084 }
2085 }
2086
2087 void writeFloats(float[] v, int off, int len) throws IOException {
2088 int limit = MAX_BLOCK_SIZE - 4;
2089 int endoff = off + len;
2090 while (off < endoff) {
2091 if (pos <= limit) {
2092 int avail = (MAX_BLOCK_SIZE - pos) >> 2;
2093 int chunklen = Math.min(endoff - off, avail);
2094 floatsToBytes(v, off, buf, pos, chunklen);
2095 off += chunklen;
2096 pos += chunklen << 2;
2097 } else {
2098 dout.writeFloat(v[off++]);
2099 }
2100 }
2101 }
2102
2103 void writeLongs(long[] v, int off, int len) throws IOException {
2104 int limit = MAX_BLOCK_SIZE - 8;
2105 int endoff = off + len;
2106 while (off < endoff) {
2107 if (pos <= limit) {
2108 int avail = (MAX_BLOCK_SIZE - pos) >> 3;
2109 int stop = Math.min(endoff, off + avail);
2110 while (off < stop) {
2111 Bits.putLong(buf, pos, v[off++]);
2112 pos += 8;
2113 }
2114 } else {
2115 dout.writeLong(v[off++]);
2116 }
2117 }
2118 }
2119
2120 void writeDoubles(double[] v, int off, int len) throws IOException {
2121 int limit = MAX_BLOCK_SIZE - 8;
2122 int endoff = off + len;
2123 while (off < endoff) {
2124 if (pos <= limit) {
2125 int avail = (MAX_BLOCK_SIZE - pos) >> 3;
2126 int chunklen = Math.min(endoff - off, avail);
2127 doublesToBytes(v, off, buf, pos, chunklen);
2128 off += chunklen;
2129 pos += chunklen << 3;
2130 } else {
2131 dout.writeDouble(v[off++]);
2132 }
2133 }
2134 }
2135
2136 /**
2137 * Returns the length in bytes of the UTF encoding of the given string.
2138 */
2139 long getUTFLength(String s) {
2140 int len = s.length();
2141 long utflen = 0;
2142 for (int off = 0; off < len; ) {
2143 int csize = Math.min(len - off, CHAR_BUF_SIZE);
2144 s.getChars(off, off + csize, cbuf, 0);
2145 for (int cpos = 0; cpos < csize; cpos++) {
2146 char c = cbuf[cpos];
2147 if (c >= 0x0001 && c <= 0x007F) {
2148 utflen++;
2149 } else if (c > 0x07FF) {
2150 utflen += 3;
2151 } else {
2152 utflen += 2;
2153 }
2154 }
2155 off += csize;
2156 }
2157 return utflen;
2158 }
2159
2160 /**
2161 * Writes the given string in UTF format. This method is used in
2162 * situations where the UTF encoding length of the string is already
2163 * known; specifying it explicitly avoids a prescan of the string to
2164 * determine its UTF length.
2165 */
2166 void writeUTF(String s, long utflen) throws IOException {
2167 if (utflen > 0xFFFFL) {
2168 throw new UTFDataFormatException();
2169 }
2170 writeShort((int) utflen);
2171 if (utflen == (long) s.length()) {
2172 writeBytes(s);
2173 } else {
2174 writeUTFBody(s);
2175 }
2176 }
2177
2178 /**
2179 * Writes given string in "long" UTF format. "Long" UTF format is
2180 * identical to standard UTF, except that it uses an 8 byte header
2181 * (instead of the standard 2 bytes) to convey the UTF encoding length.
2182 */
2183 void writeLongUTF(String s) throws IOException {
2184 writeLongUTF(s, getUTFLength(s));
2185 }
2186
2187 /**
2188 * Writes given string in "long" UTF format, where the UTF encoding
2189 * length of the string is already known.
2190 */
2191 void writeLongUTF(String s, long utflen) throws IOException {
2192 writeLong(utflen);
2193 if (utflen == (long) s.length()) {
2194 writeBytes(s);
2195 } else {
2196 writeUTFBody(s);
2197 }
2198 }
2199
2200 /**
2201 * Writes the "body" (i.e., the UTF representation minus the 2-byte or
2202 * 8-byte length header) of the UTF encoding for the given string.
2203 */
2204 private void writeUTFBody(String s) throws IOException {
2205 int limit = MAX_BLOCK_SIZE - 3;
2206 int len = s.length();
2207 for (int off = 0; off < len; ) {
2208 int csize = Math.min(len - off, CHAR_BUF_SIZE);
2209 s.getChars(off, off + csize, cbuf, 0);
2210 for (int cpos = 0; cpos < csize; cpos++) {
2211 char c = cbuf[cpos];
2212 if (pos <= limit) {
2213 if (c <= 0x007F && c != 0) {
2214 buf[pos++] = (byte) c;
2215 } else if (c > 0x07FF) {
2216 buf[pos + 2] = (byte) (0x80 | ((c >> 0) & 0x3F));
2217 buf[pos + 1] = (byte) (0x80 | ((c >> 6) & 0x3F));
2218 buf[pos + 0] = (byte) (0xE0 | ((c >> 12) & 0x0F));
2219 pos += 3;
2220 } else {
2221 buf[pos + 1] = (byte) (0x80 | ((c >> 0) & 0x3F));
2222 buf[pos + 0] = (byte) (0xC0 | ((c >> 6) & 0x1F));
2223 pos += 2;
2224 }
2225 } else { // write one byte at a time to normalize block
2226 if (c <= 0x007F && c != 0) {
2227 write(c);
2228 } else if (c > 0x07FF) {
2229 write(0xE0 | ((c >> 12) & 0x0F));
2230 write(0x80 | ((c >> 6) & 0x3F));
2231 write(0x80 | ((c >> 0) & 0x3F));
2232 } else {
2233 write(0xC0 | ((c >> 6) & 0x1F));
2234 write(0x80 | ((c >> 0) & 0x3F));
2235 }
2236 }
2237 }
2238 off += csize;
2239 }
2240 }
2241 }
2242
2243 /**
2244 * Lightweight identity hash table which maps objects to integer handles,
2245 * assigned in ascending order.
2246 */
2247 private static class HandleTable {
2248
2249 /* number of mappings in table/next available handle */
2250 private int size;
2251 /* size threshold determining when to expand hash spine */
2252 private int threshold;
2253 /* factor for computing size threshold */
2254 private final float loadFactor;
2255 /* maps hash value -> candidate handle value */
2256 private int[] spine;
2257 /* maps handle value -> next candidate handle value */
2258 private int[] next;
2259 /* maps handle value -> associated object */
2260 private Object[] objs;
2261
2262 /**
2263 * Creates new HandleTable with given capacity and load factor.
2264 */
2265 HandleTable(int initialCapacity, float loadFactor) {
2266 this.loadFactor = loadFactor;
2267 spine = new int[initialCapacity];
2268 next = new int[initialCapacity];
2269 objs = new Object[initialCapacity];
2270 threshold = (int) (initialCapacity * loadFactor);
2271 clear();
2272 }
2273
2274 /**
2275 * Assigns next available handle to given object, and returns handle
2276 * value. Handles are assigned in ascending order starting at 0.
2277 */
2278 int assign(Object obj) {
2279 if (size >= next.length) {
2280 growEntries();
2281 }
2282 if (size >= threshold) {
2283 growSpine();
2284 }
2285 insert(obj, size);
2286 return size++;
2287 }
2288
2289 /**
2290 * Looks up and returns handle associated with given object, or -1 if
2291 * no mapping found.
2292 */
2293 int lookup(Object obj) {
2294 if (size == 0) {
2295 return -1;
2296 }
2297 int index = hash(obj) % spine.length;
2298 for (int i = spine[index]; i >= 0; i = next[i]) {
2299 if (objs[i] == obj) {
2300 return i;
2301 }
2302 }
2303 return -1;
2304 }
2305
2306 /**
2307 * Resets table to its initial (empty) state.
2308 */
2309 void clear() {
2310 Arrays.fill(spine, -1);
2311 Arrays.fill(objs, 0, size, null);
2312 size = 0;
2313 }
2314
2315 /**
2316 * Returns the number of mappings currently in table.
2317 */
2318 int size() {
2319 return size;
2320 }
2321
2322 /**
2323 * Inserts mapping object -> handle mapping into table. Assumes table
2324 * is large enough to accommodate new mapping.
2325 */
2326 private void insert(Object obj, int handle) {
2327 int index = hash(obj) % spine.length;
2328 objs[handle] = obj;
2329 next[handle] = spine[index];
2330 spine[index] = handle;
2331 }
2332
2333 /**
2334 * Expands the hash "spine" -- equivalent to increasing the number of
2335 * buckets in a conventional hash table.
2336 */
2337 private void growSpine() {
2338 spine = new int[(spine.length << 1) + 1];
2339 threshold = (int) (spine.length * loadFactor);
2340 Arrays.fill(spine, -1);
2341 for (int i = 0; i < size; i++) {
2342 insert(objs[i], i);
2343 }
2344 }
2345
2346 /**
2347 * Increases hash table capacity by lengthening entry arrays.
2348 */
2349 private void growEntries() {
2350 int newLength = (next.length << 1) + 1;
2351 int[] newNext = new int[newLength];
2352 System.arraycopy(next, 0, newNext, 0, size);
2353 next = newNext;
2354
2355 Object[] newObjs = new Object[newLength];
2356 System.arraycopy(objs, 0, newObjs, 0, size);
2357 objs = newObjs;
2358 }
2359
2360 /**
2361 * Returns hash value for given object.
2362 */
2363 private int hash(Object obj) {
2364 return System.identityHashCode(obj) & 0x7FFFFFFF;
2365 }
2366 }
2367
2368 /**
2369 * Lightweight identity hash table which maps objects to replacement
2370 * objects.
2371 */
2372 private static class ReplaceTable {
2373
2374 /* maps object -> index */
2375 private final HandleTable htab;
2376 /* maps index -> replacement object */
2377 private Object[] reps;
2378
2379 /**
2380 * Creates new ReplaceTable with given capacity and load factor.
2381 */
2382 ReplaceTable(int initialCapacity, float loadFactor) {
2383 htab = new HandleTable(initialCapacity, loadFactor);
2384 reps = new Object[initialCapacity];
2385 }
2386
2387 /**
2388 * Enters mapping from object to replacement object.
2389 */
2390 void assign(Object obj, Object rep) {
2391 int index = htab.assign(obj);
2392 while (index >= reps.length) {
2393 grow();
2394 }
2395 reps[index] = rep;
2396 }
2397
2398 /**
2399 * Looks up and returns replacement for given object. If no
2400 * replacement is found, returns the lookup object itself.
2401 */
2402 Object lookup(Object obj) {
2403 int index = htab.lookup(obj);
2404 return (index >= 0) ? reps[index] : obj;
2405 }
2406
2407 /**
2408 * Resets table to its initial (empty) state.
2409 */
2410 void clear() {
2411 Arrays.fill(reps, 0, htab.size(), null);
2412 htab.clear();
2413 }
2414
2415 /**
2416 * Returns the number of mappings currently in table.
2417 */
2418 int size() {
2419 return htab.size();
2420 }
2421
2422 /**
2423 * Increases table capacity.
2424 */
2425 private void grow() {
2426 Object[] newReps = new Object[(reps.length << 1) + 1];
2427 System.arraycopy(reps, 0, newReps, 0, reps.length);
2428 reps = newReps;
2429 }
2430 }
2431
2432 /**
2433 * Stack to keep debug information about the state of the
2434 * serialization process, for embedding in exception messages.
2435 */
2436 private static class DebugTraceInfoStack {
2437 private final List<String> stack;
2438
2439 DebugTraceInfoStack() {
2440 stack = new ArrayList<>();
2441 }
2442
2443 /**
2444 * Removes all of the elements from enclosed list.
2445 */
2446 void clear() {
2447 stack.clear();
2448 }
2449
2450 /**
2451 * Removes the object at the top of enclosed list.
2452 */
2453 void pop() {
2454 stack.remove(stack.size()-1);
2455 }
2456
2457 /**
2458 * Pushes a String onto the top of enclosed list.
2459 */
2460 void push(String entry) {
2461 stack.add("\t- " + entry);
2462 }
2463
2464 /**
2465 * Returns a string representation of this object
2466 */
2467 public String toString() {
2468 StringBuilder buffer = new StringBuilder();
2469 if (!stack.isEmpty()) {
2470 for(int i = stack.size(); i > 0; i-- ) {
2471 buffer.append(stack.get(i - 1));
2472 if (i != 1)
2473 buffer.append('\n');
2474 }
2475 }
2476 return buffer.toString();
2477 }
2478 }
2479
2480 }