1 /*
2 * Copyright (c) 1996, 2014, 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.StringJoiner;
36 import java.util.concurrent.ConcurrentHashMap;
37 import java.util.concurrent.ConcurrentMap;
38 import static java.io.ObjectStreamClass.processQueue;
39 import sun.reflect.misc.ReflectUtil;
40
41 /**
42 * An ObjectOutputStream writes primitive data types and graphs of Java objects
43 * to an OutputStream. The objects can be read (reconstituted) using an
44 * ObjectInputStream. Persistent storage of objects can be accomplished by
45 * using a file for the stream. If the stream is a network socket stream, the
46 * objects can be reconstituted on another host or in another process.
47 *
48 * <p>Only objects that support the java.io.Serializable interface can be
49 * written to streams. The class of each serializable object is encoded
50 * including the class name and signature of the class, the values of the
51 * object's fields and arrays, and the closure of any other objects referenced
52 * from the initial objects.
53 *
54 * <p>The method writeObject is used to write an object to the stream. Any
55 * object, including Strings and arrays, is written with writeObject. Multiple
56 * objects or primitives can be written to the stream. The objects must be
57 * read back from the corresponding ObjectInputstream with the same types and
58 * in the same order as they were written.
59 *
60 * <p>Primitive data types can also be written to the stream using the
61 * appropriate methods from DataOutput. Strings can also be written using the
62 * writeUTF method.
63 *
64 * <p>The default serialization mechanism for an object writes the class of the
65 * object, the class signature, and the values of all non-transient and
66 * non-static fields. References to other objects (except in transient or
67 * static fields) cause those objects to be written also. Multiple references
68 * to a single object are encoded using a reference sharing mechanism so that
69 * graphs of objects can be restored to the same shape as when the original was
70 * written.
71 *
72 * <p>For example to write an object that can be read by the example in
73 * ObjectInputStream:
74 * <br>
75 * <pre>
76 * FileOutputStream fos = new FileOutputStream("t.tmp");
77 * ObjectOutputStream oos = new ObjectOutputStream(fos);
78 *
79 * oos.writeInt(12345);
80 * oos.writeObject("Today");
81 * oos.writeObject(new Date());
82 *
83 * oos.close();
84 * </pre>
85 *
86 * <p>Classes that require special handling during the serialization and
87 * deserialization process must implement special methods with these exact
88 * signatures:
89 * <br>
90 * <pre>
91 * private void readObject(java.io.ObjectInputStream stream)
92 * throws IOException, ClassNotFoundException;
93 * private void writeObject(java.io.ObjectOutputStream stream)
94 * throws IOException
95 * private void readObjectNoData()
96 * throws ObjectStreamException;
97 * </pre>
98 *
99 * <p>The writeObject method is responsible for writing the state of the object
100 * for its particular class so that the corresponding readObject method can
101 * restore it. The method does not need to concern itself with the state
102 * belonging to the object's superclasses or subclasses. State is saved by
103 * writing the individual fields to the ObjectOutputStream using the
104 * writeObject method or by using the methods for primitive data types
105 * supported by DataOutput.
106 *
107 * <p>Serialization does not write out the fields of any object that does not
108 * implement the java.io.Serializable interface. Subclasses of Objects that
109 * are not serializable can be serializable. In this case the non-serializable
110 * class must have a no-arg constructor to allow its fields to be initialized.
111 * In this case it is the responsibility of the subclass to save and restore
112 * the state of the non-serializable class. It is frequently the case that the
113 * fields of that class are accessible (public, package, or protected) or that
114 * there are get and set methods that can be used to restore the state.
115 *
116 * <p>Serialization of an object can be prevented by implementing writeObject
117 * and readObject methods that throw the NotSerializableException. The
118 * exception will be caught by the ObjectOutputStream and abort the
119 * serialization process.
120 *
121 * <p>Implementing the Externalizable interface allows the object to assume
122 * complete control over the contents and format of the object's serialized
123 * form. The methods of the Externalizable interface, writeExternal and
124 * readExternal, are called to save and restore the objects state. When
125 * implemented by a class they can write and read their own state using all of
126 * the methods of ObjectOutput and ObjectInput. It is the responsibility of
127 * the objects to handle any versioning that occurs.
128 *
129 * <p>Enum constants are serialized differently than ordinary serializable or
130 * externalizable objects. The serialized form of an enum constant consists
131 * solely of its name; field values of the constant are not transmitted. To
132 * serialize an enum constant, ObjectOutputStream writes the string returned by
133 * the constant's name method. Like other serializable or externalizable
134 * objects, enum constants can function as the targets of back references
135 * appearing subsequently in the serialization stream. The process by which
136 * enum constants are serialized cannot be customized; any class-specific
137 * writeObject and writeReplace methods defined by enum types are ignored
138 * during serialization. Similarly, any serialPersistentFields or
139 * serialVersionUID field declarations are also ignored--all enum types have a
140 * fixed serialVersionUID of 0L.
141 *
142 * <p>Primitive data, excluding serializable fields and externalizable data, is
143 * written to the ObjectOutputStream in block-data records. A block data record
144 * is composed of a header and data. The block data header consists of a marker
145 * and the number of bytes to follow the header. Consecutive primitive data
146 * writes are merged into one block-data record. The blocking factor used for
147 * a block-data record will be 1024 bytes. Each block-data record will be
148 * filled up to 1024 bytes, or be written whenever there is a termination of
149 * block-data mode. Calls to the ObjectOutputStream methods writeObject,
150 * defaultWriteObject and writeFields initially terminate any existing
151 * block-data record.
152 *
153 * @author Mike Warres
154 * @author Roger Riggs
155 * @see java.io.DataOutput
156 * @see java.io.ObjectInputStream
157 * @see java.io.Serializable
158 * @see java.io.Externalizable
159 * @see <a href="../../../platform/serialization/spec/output.html">Object Serialization Specification, Section 2, Object Output Classes</a>
160 * @since 1.1
161 */
162 public class ObjectOutputStream
163 extends OutputStream implements ObjectOutput, ObjectStreamConstants
164 {
165
166 private static class Caches {
167 /** cache of subclass security audit results */
168 static final ConcurrentMap<WeakClassKey,Boolean> subclassAudits =
169 new ConcurrentHashMap<>();
170
171 /** queue for WeakReferences to audited subclasses */
172 static final ReferenceQueue<Class<?>> subclassAuditsQueue =
173 new ReferenceQueue<>();
174 }
175
176 /** filter stream for handling block data conversion */
177 private final BlockDataOutputStream bout;
178 /** obj -> wire handle map */
179 private final HandleTable handles;
180 /** obj -> replacement obj map */
181 private final ReplaceTable subs;
182 /** stream protocol version */
183 private int protocol = PROTOCOL_VERSION_2;
184 /** recursion depth */
185 private int depth;
186
187 /** buffer for writing primitive field values */
188 private byte[] primVals;
189
190 /** if true, invoke writeObjectOverride() instead of writeObject() */
191 private final boolean enableOverride;
192 /** if true, invoke replaceObject() */
193 private boolean enableReplace;
194
195 // values below valid only during upcalls to writeObject()/writeExternal()
196 /**
197 * Context during upcalls to class-defined writeObject methods; holds
198 * object currently being serialized and descriptor for current class.
199 * Null when not during writeObject upcall.
200 */
201 private SerialCallbackContext curContext;
202 /** current PutField object */
203 private PutFieldImpl curPut;
204
205 /** custom storage for debug trace info */
206 private final DebugTraceInfoStack debugInfoStack;
207
208 /**
209 * value of "sun.io.serialization.extendedDebugInfo" property,
210 * as true or false for extended information about exception's place
211 */
212 private static final boolean extendedDebugInfo =
213 java.security.AccessController.doPrivileged(
214 new sun.security.action.GetBooleanAction(
215 "sun.io.serialization.extendedDebugInfo")).booleanValue();
216
217 /**
218 * Creates an ObjectOutputStream that writes to the specified OutputStream.
219 * This constructor writes the serialization stream header to the
220 * underlying stream; callers may wish to flush the stream immediately to
221 * ensure that constructors for receiving ObjectInputStreams will not block
222 * when reading the header.
223 *
224 * <p>If a security manager is installed, this constructor will check for
225 * the "enableSubclassImplementation" SerializablePermission when invoked
226 * directly or indirectly by the constructor of a subclass which overrides
227 * the ObjectOutputStream.putFields or ObjectOutputStream.writeUnshared
228 * methods.
229 *
230 * @param out output stream to write to
231 * @throws IOException if an I/O error occurs while writing stream header
232 * @throws SecurityException if untrusted subclass illegally overrides
233 * security-sensitive methods
234 * @throws NullPointerException if <code>out</code> is <code>null</code>
235 * @since 1.4
236 * @see ObjectOutputStream#ObjectOutputStream()
237 * @see ObjectOutputStream#putFields()
238 * @see ObjectInputStream#ObjectInputStream(InputStream)
239 */
240 public ObjectOutputStream(OutputStream out) throws IOException {
241 verifySubclass();
242 bout = new BlockDataOutputStream(out);
243 handles = new HandleTable(10, (float) 3.00);
244 subs = new ReplaceTable(10, (float) 3.00);
245 enableOverride = false;
246 writeStreamHeader();
247 bout.setBlockDataMode(true);
248 if (extendedDebugInfo) {
249 debugInfoStack = new DebugTraceInfoStack();
250 } else {
251 debugInfoStack = null;
252 }
253 }
254
255 /**
256 * Provide a way for subclasses that are completely reimplementing
257 * ObjectOutputStream to not have to allocate private data just used by
258 * this implementation of ObjectOutputStream.
259 *
260 * <p>If there is a security manager installed, this method first calls the
261 * security manager's <code>checkPermission</code> method with a
262 * <code>SerializablePermission("enableSubclassImplementation")</code>
263 * permission to ensure it's ok to enable subclassing.
264 *
265 * @throws SecurityException if a security manager exists and its
266 * <code>checkPermission</code> method denies enabling
267 * subclassing.
268 * @throws IOException if an I/O error occurs while creating this stream
269 * @see SecurityManager#checkPermission
270 * @see java.io.SerializablePermission
271 */
272 protected ObjectOutputStream() throws IOException, SecurityException {
273 SecurityManager sm = System.getSecurityManager();
274 if (sm != null) {
275 sm.checkPermission(SUBCLASS_IMPLEMENTATION_PERMISSION);
276 }
277 bout = null;
278 handles = null;
279 subs = null;
280 enableOverride = true;
281 debugInfoStack = null;
282 }
283
284 /**
285 * Specify stream protocol version to use when writing the stream.
286 *
287 * <p>This routine provides a hook to enable the current version of
288 * Serialization to write in a format that is backwards compatible to a
289 * previous version of the stream format.
290 *
291 * <p>Every effort will be made to avoid introducing additional
292 * backwards incompatibilities; however, sometimes there is no
293 * other alternative.
294 *
295 * @param version use ProtocolVersion from java.io.ObjectStreamConstants.
296 * @throws IllegalStateException if called after any objects
297 * have been serialized.
298 * @throws IllegalArgumentException if invalid version is passed in.
299 * @throws IOException if I/O errors occur
300 * @see java.io.ObjectStreamConstants#PROTOCOL_VERSION_1
301 * @see java.io.ObjectStreamConstants#PROTOCOL_VERSION_2
302 * @since 1.2
303 */
304 public void useProtocolVersion(int version) throws IOException {
305 if (handles.size() != 0) {
306 // REMIND: implement better check for pristine stream?
307 throw new IllegalStateException("stream non-empty");
308 }
309 switch (version) {
310 case PROTOCOL_VERSION_1:
311 case PROTOCOL_VERSION_2:
312 protocol = version;
313 break;
314
315 default:
316 throw new IllegalArgumentException(
317 "unknown version: " + version);
318 }
319 }
320
321 /**
322 * Write the specified object to the ObjectOutputStream. The class of the
323 * object, the signature of the class, and the values of the non-transient
324 * and non-static fields of the class and all of its supertypes are
325 * written. Default serialization for a class can be overridden using the
326 * writeObject and the readObject methods. Objects referenced by this
327 * object are written transitively so that a complete equivalent graph of
328 * objects can be reconstructed by an ObjectInputStream.
329 *
330 * <p>Exceptions are thrown for problems with the OutputStream and for
331 * classes that should not be serialized. All exceptions are fatal to the
332 * OutputStream, which is left in an indeterminate state, and it is up to
333 * the caller to ignore or recover the stream state.
334 *
335 * @throws InvalidClassException Something is wrong with a class used by
336 * serialization.
337 * @throws NotSerializableException Some object to be serialized does not
338 * implement the java.io.Serializable interface.
339 * @throws IOException Any exception thrown by the underlying
340 * OutputStream.
341 */
342 public final void writeObject(Object obj) throws IOException {
343 if (enableOverride) {
344 writeObjectOverride(obj);
345 return;
346 }
347 try {
348 writeObject0(obj, false);
349 } catch (IOException ex) {
350 if (depth == 0) {
351 writeFatalException(ex);
352 }
353 throw ex;
354 }
355 }
356
357 /**
358 * Method used by subclasses to override the default writeObject method.
359 * This method is called by trusted subclasses of ObjectInputStream that
360 * constructed ObjectInputStream using the protected no-arg constructor.
361 * The subclass is expected to provide an override method with the modifier
362 * "final".
363 *
364 * @param obj object to be written to the underlying stream
365 * @throws IOException if there are I/O errors while writing to the
366 * underlying stream
367 * @see #ObjectOutputStream()
368 * @see #writeObject(Object)
369 * @since 1.2
370 */
371 protected void writeObjectOverride(Object obj) throws IOException {
372 }
373
374 /**
375 * Writes an "unshared" object to the ObjectOutputStream. This method is
376 * identical to writeObject, except that it always writes the given object
377 * as a new, unique object in the stream (as opposed to a back-reference
378 * pointing to a previously serialized instance). Specifically:
379 * <ul>
380 * <li>An object written via writeUnshared is always serialized in the
381 * same manner as a newly appearing object (an object that has not
382 * been written to the stream yet), regardless of whether or not the
383 * object has been written previously.
384 *
385 * <li>If writeObject is used to write an object that has been previously
386 * written with writeUnshared, the previous writeUnshared operation
387 * is treated as if it were a write of a separate object. In other
388 * words, ObjectOutputStream will never generate back-references to
389 * object data written by calls to writeUnshared.
390 * </ul>
391 * While writing an object via writeUnshared does not in itself guarantee a
392 * unique reference to the object when it is deserialized, it allows a
393 * single object to be defined multiple times in a stream, so that multiple
394 * calls to readUnshared by the receiver will not conflict. Note that the
395 * rules described above only apply to the base-level object written with
396 * writeUnshared, and not to any transitively referenced sub-objects in the
397 * object graph to be serialized.
398 *
399 * <p>ObjectOutputStream subclasses which override this method can only be
400 * constructed in security contexts possessing the
401 * "enableSubclassImplementation" SerializablePermission; any attempt to
402 * instantiate such a subclass without this permission will cause a
403 * SecurityException to be thrown.
404 *
405 * @param obj object to write to stream
406 * @throws NotSerializableException if an object in the graph to be
407 * serialized does not implement the Serializable interface
408 * @throws InvalidClassException if a problem exists with the class of an
409 * object to be serialized
410 * @throws IOException if an I/O error occurs during serialization
411 * @since 1.4
412 */
413 public void writeUnshared(Object obj) throws IOException {
414 try {
415 writeObject0(obj, true);
416 } catch (IOException ex) {
417 if (depth == 0) {
418 writeFatalException(ex);
419 }
420 throw ex;
421 }
422 }
423
424 /**
425 * Write the non-static and non-transient fields of the current class to
426 * this stream. This may only be called from the writeObject method of the
427 * class being serialized. It will throw the NotActiveException if it is
428 * called otherwise.
429 *
430 * @throws IOException if I/O errors occur while writing to the underlying
431 * <code>OutputStream</code>
432 */
433 public void defaultWriteObject() throws IOException {
434 SerialCallbackContext ctx = curContext;
435 if (ctx == null) {
436 throw new NotActiveException("not in call to writeObject");
437 }
438 Object curObj = ctx.getObj();
439 ObjectStreamClass curDesc = ctx.getDesc();
440 bout.setBlockDataMode(false);
441 defaultWriteFields(curObj, curDesc);
442 bout.setBlockDataMode(true);
443 }
444
445 /**
446 * Retrieve the object used to buffer persistent fields to be written to
447 * the stream. The fields will be written to the stream when writeFields
448 * method is called.
449 *
450 * @return an instance of the class Putfield that holds the serializable
451 * fields
452 * @throws IOException if I/O errors occur
453 * @since 1.2
454 */
455 public ObjectOutputStream.PutField putFields() throws IOException {
456 if (curPut == null) {
457 SerialCallbackContext ctx = curContext;
458 if (ctx == null) {
459 throw new NotActiveException("not in call to writeObject");
460 }
461 ctx.checkAndSetUsed();
462 ObjectStreamClass curDesc = ctx.getDesc();
463 curPut = new PutFieldImpl(curDesc);
464 }
465 return curPut;
466 }
467
468 /**
469 * Write the buffered fields to the stream.
470 *
471 * @throws IOException if I/O errors occur while writing to the underlying
472 * stream
473 * @throws NotActiveException Called when a classes writeObject method was
474 * not called to write the state of the object.
475 * @since 1.2
476 */
477 public void writeFields() throws IOException {
478 if (curPut == null) {
479 throw new NotActiveException("no current PutField object");
480 }
481 bout.setBlockDataMode(false);
482 curPut.writeFields();
483 bout.setBlockDataMode(true);
484 }
485
486 /**
487 * Reset will disregard the state of any objects already written to the
488 * stream. The state is reset to be the same as a new ObjectOutputStream.
489 * The current point in the stream is marked as reset so the corresponding
490 * ObjectInputStream will be reset at the same point. Objects previously
491 * written to the stream will not be referred to as already being in the
492 * stream. They will be written to the stream again.
493 *
494 * @throws IOException if reset() is invoked while serializing an object.
495 */
496 public void reset() throws IOException {
497 if (depth != 0) {
498 throw new IOException("stream active");
499 }
500 bout.setBlockDataMode(false);
501 bout.writeByte(TC_RESET);
502 clear();
503 bout.setBlockDataMode(true);
504 }
505
506 /**
507 * Subclasses may implement this method to allow class data to be stored in
508 * the stream. By default this method does nothing. The corresponding
509 * method in ObjectInputStream is resolveClass. This method is called
510 * exactly once for each unique class in the stream. The class name and
511 * signature will have already been written to the stream. This method may
512 * make free use of the ObjectOutputStream to save any representation of
513 * the class it deems suitable (for example, the bytes of the class file).
514 * The resolveClass method in the corresponding subclass of
515 * ObjectInputStream must read and use any data or objects written by
516 * annotateClass.
517 *
518 * @param cl the class to annotate custom data for
519 * @throws IOException Any exception thrown by the underlying
520 * OutputStream.
521 */
522 protected void annotateClass(Class<?> cl) throws IOException {
523 }
524
525 /**
526 * Subclasses may implement this method to store custom data in the stream
527 * along with descriptors for dynamic proxy classes.
528 *
529 * <p>This method is called exactly once for each unique proxy class
530 * descriptor in the stream. The default implementation of this method in
531 * <code>ObjectOutputStream</code> does nothing.
532 *
533 * <p>The corresponding method in <code>ObjectInputStream</code> is
534 * <code>resolveProxyClass</code>. For a given subclass of
535 * <code>ObjectOutputStream</code> that overrides this method, the
536 * <code>resolveProxyClass</code> method in the corresponding subclass of
537 * <code>ObjectInputStream</code> must read any data or objects written by
538 * <code>annotateProxyClass</code>.
539 *
540 * @param cl the proxy class to annotate custom data for
541 * @throws IOException any exception thrown by the underlying
542 * <code>OutputStream</code>
543 * @see ObjectInputStream#resolveProxyClass(String[])
544 * @since 1.3
545 */
546 protected void annotateProxyClass(Class<?> cl) throws IOException {
547 }
548
549 /**
550 * This method will allow trusted subclasses of ObjectOutputStream to
551 * substitute one object for another during serialization. Replacing
552 * objects is disabled until enableReplaceObject is called. The
553 * enableReplaceObject method checks that the stream requesting to do
554 * replacement can be trusted. The first occurrence of each object written
555 * into the serialization stream is passed to replaceObject. Subsequent
556 * references to the object are replaced by the object returned by the
557 * original call to replaceObject. To ensure that the private state of
558 * objects is not unintentionally exposed, only trusted streams may use
559 * replaceObject.
560 *
561 * <p>The ObjectOutputStream.writeObject method takes a parameter of type
562 * Object (as opposed to type Serializable) to allow for cases where
563 * non-serializable objects are replaced by serializable ones.
564 *
565 * <p>When a subclass is replacing objects it must insure that either a
566 * complementary substitution must be made during deserialization or that
567 * the substituted object is compatible with every field where the
568 * reference will be stored. Objects whose type is not a subclass of the
569 * type of the field or array element abort the serialization by raising an
570 * exception and the object is not be stored.
571 *
572 * <p>This method is called only once when each object is first
573 * encountered. All subsequent references to the object will be redirected
574 * to the new object. This method should return the object to be
575 * substituted or the original object.
576 *
577 * <p>Null can be returned as the object to be substituted, but may cause
578 * NullReferenceException in classes that contain references to the
579 * original object since they may be expecting an object instead of
580 * null.
581 *
582 * @param obj the object to be replaced
583 * @return the alternate object that replaced the specified one
584 * @throws IOException Any exception thrown by the underlying
585 * OutputStream.
586 */
587 protected Object replaceObject(Object obj) throws IOException {
588 return obj;
589 }
590
591 /**
592 * Enable the stream to do replacement of objects in the stream. When
593 * enabled, the replaceObject method is called for every object being
594 * serialized.
595 *
596 * <p>If <code>enable</code> is true, and there is a security manager
597 * installed, this method first calls the security manager's
598 * <code>checkPermission</code> method with a
599 * <code>SerializablePermission("enableSubstitution")</code> permission to
600 * ensure it's ok to enable the stream to do replacement of objects in the
601 * stream.
602 *
603 * @param enable boolean parameter to enable replacement of objects
604 * @return the previous setting before this method was invoked
605 * @throws SecurityException if a security manager exists and its
606 * <code>checkPermission</code> method denies enabling the stream
607 * to do replacement of objects in the stream.
608 * @see SecurityManager#checkPermission
609 * @see java.io.SerializablePermission
610 */
611 protected boolean enableReplaceObject(boolean enable)
612 throws SecurityException
613 {
614 if (enable == enableReplace) {
615 return enable;
616 }
617 if (enable) {
618 SecurityManager sm = System.getSecurityManager();
619 if (sm != null) {
620 sm.checkPermission(SUBSTITUTION_PERMISSION);
621 }
622 }
623 enableReplace = enable;
624 return !enableReplace;
625 }
626
627 /**
628 * The writeStreamHeader method is provided so subclasses can append or
629 * prepend their own header to the stream. It writes the magic number and
630 * version to the stream.
631 *
632 * @throws IOException if I/O errors occur while writing to the underlying
633 * stream
634 */
635 protected void writeStreamHeader() throws IOException {
636 bout.writeShort(STREAM_MAGIC);
637 bout.writeShort(STREAM_VERSION);
638 }
639
640 /**
641 * Write the specified class descriptor to the ObjectOutputStream. Class
642 * descriptors are used to identify the classes of objects written to the
643 * stream. Subclasses of ObjectOutputStream may override this method to
644 * customize the way in which class descriptors are written to the
645 * serialization stream. The corresponding method in ObjectInputStream,
646 * <code>readClassDescriptor</code>, should then be overridden to
647 * reconstitute the class descriptor from its custom stream representation.
648 * By default, this method writes class descriptors according to the format
649 * defined in the Object Serialization specification.
650 *
651 * <p>Note that this method will only be called if the ObjectOutputStream
652 * is not using the old serialization stream format (set by calling
653 * ObjectOutputStream's <code>useProtocolVersion</code> method). If this
654 * serialization stream is using the old format
655 * (<code>PROTOCOL_VERSION_1</code>), the class descriptor will be written
656 * internally in a manner that cannot be overridden or customized.
657 *
658 * @param desc class descriptor to write to the stream
659 * @throws IOException If an I/O error has occurred.
660 * @see java.io.ObjectInputStream#readClassDescriptor()
661 * @see #useProtocolVersion(int)
662 * @see java.io.ObjectStreamConstants#PROTOCOL_VERSION_1
663 * @since 1.3
664 */
665 protected void writeClassDescriptor(ObjectStreamClass desc)
666 throws IOException
667 {
668 desc.writeNonProxy(this);
669 }
670
671 /**
672 * Writes a byte. This method will block until the byte is actually
673 * written.
674 *
675 * @param val the byte to be written to the stream
676 * @throws IOException If an I/O error has occurred.
677 */
678 public void write(int val) throws IOException {
679 bout.write(val);
680 }
681
682 /**
683 * Writes an array of bytes. This method will block until the bytes are
684 * actually written.
685 *
686 * @param buf the data to be written
687 * @throws IOException If an I/O error has occurred.
688 */
689 public void write(byte[] buf) throws IOException {
690 bout.write(buf, 0, buf.length, false);
691 }
692
693 /**
694 * Writes a sub array of bytes.
695 *
696 * @param buf the data to be written
697 * @param off the start offset in the data
698 * @param len the number of bytes that are written
699 * @throws IOException If an I/O error has occurred.
700 */
701 public void write(byte[] buf, int off, int len) throws IOException {
702 if (buf == null) {
703 throw new NullPointerException();
704 }
705 int endoff = off + len;
706 if (off < 0 || len < 0 || endoff > buf.length || endoff < 0) {
707 throw new IndexOutOfBoundsException();
708 }
709 bout.write(buf, off, len, false);
710 }
711
712 /**
713 * Flushes the stream. This will write any buffered output bytes and flush
714 * through to the underlying stream.
715 *
716 * @throws IOException If an I/O error has occurred.
717 */
718 public void flush() throws IOException {
719 bout.flush();
720 }
721
722 /**
723 * Drain any buffered data in ObjectOutputStream. Similar to flush but
724 * does not propagate the flush to the underlying stream.
725 *
726 * @throws IOException if I/O errors occur while writing to the underlying
727 * stream
728 */
729 protected void drain() throws IOException {
730 bout.drain();
731 }
732
733 /**
734 * Closes the stream. This method must be called to release any resources
735 * associated with the stream.
736 *
737 * @throws IOException If an I/O error has occurred.
738 */
739 public void close() throws IOException {
740 flush();
741 clear();
742 bout.close();
743 }
744
745 /**
746 * Writes a boolean.
747 *
748 * @param val the boolean to be written
749 * @throws IOException if I/O errors occur while writing to the underlying
750 * stream
751 */
752 public void writeBoolean(boolean val) throws IOException {
753 bout.writeBoolean(val);
754 }
755
756 /**
757 * Writes an 8 bit byte.
758 *
759 * @param val the byte value to be written
760 * @throws IOException if I/O errors occur while writing to the underlying
761 * stream
762 */
763 public void writeByte(int val) throws IOException {
764 bout.writeByte(val);
765 }
766
767 /**
768 * Writes a 16 bit short.
769 *
770 * @param val the short value to be written
771 * @throws IOException if I/O errors occur while writing to the underlying
772 * stream
773 */
774 public void writeShort(int val) throws IOException {
775 bout.writeShort(val);
776 }
777
778 /**
779 * Writes a 16 bit char.
780 *
781 * @param val the char value to be written
782 * @throws IOException if I/O errors occur while writing to the underlying
783 * stream
784 */
785 public void writeChar(int val) throws IOException {
786 bout.writeChar(val);
787 }
788
789 /**
790 * Writes a 32 bit int.
791 *
792 * @param val the integer value to be written
793 * @throws IOException if I/O errors occur while writing to the underlying
794 * stream
795 */
796 public void writeInt(int val) throws IOException {
797 bout.writeInt(val);
798 }
799
800 /**
801 * Writes a 64 bit long.
802 *
803 * @param val the long value to be written
804 * @throws IOException if I/O errors occur while writing to the underlying
805 * stream
806 */
807 public void writeLong(long val) throws IOException {
808 bout.writeLong(val);
809 }
810
811 /**
812 * Writes a 32 bit float.
813 *
814 * @param val the float value to be written
815 * @throws IOException if I/O errors occur while writing to the underlying
816 * stream
817 */
818 public void writeFloat(float val) throws IOException {
819 bout.writeFloat(val);
820 }
821
822 /**
823 * Writes a 64 bit double.
824 *
825 * @param val the double value to be written
826 * @throws IOException if I/O errors occur while writing to the underlying
827 * stream
828 */
829 public void writeDouble(double val) throws IOException {
830 bout.writeDouble(val);
831 }
832
833 /**
834 * Writes a String as a sequence of bytes.
835 *
836 * @param str the String of bytes to be written
837 * @throws IOException if I/O errors occur while writing to the underlying
838 * stream
839 */
840 public void writeBytes(String str) throws IOException {
841 bout.writeBytes(str);
842 }
843
844 /**
845 * Writes a String as a sequence of chars.
846 *
847 * @param str the String of chars to be written
848 * @throws IOException if I/O errors occur while writing to the underlying
849 * stream
850 */
851 public void writeChars(String str) throws IOException {
852 bout.writeChars(str);
853 }
854
855 /**
856 * Primitive data write of this String in
857 * <a href="DataInput.html#modified-utf-8">modified UTF-8</a>
858 * format. Note that there is a
859 * significant difference between writing a String into the stream as
860 * primitive data or as an Object. A String instance written by writeObject
861 * is written into the stream as a String initially. Future writeObject()
862 * calls write references to the string into the stream.
863 *
864 * @param str the String to be written
865 * @throws IOException if I/O errors occur while writing to the underlying
866 * stream
867 */
868 public void writeUTF(String str) throws IOException {
869 bout.writeUTF(str);
870 }
871
872 /**
873 * Provide programmatic access to the persistent fields to be written
874 * to ObjectOutput.
875 *
876 * @since 1.2
877 */
878 public static abstract class PutField {
879
880 /**
881 * Put the value of the named boolean field into the persistent field.
882 *
883 * @param name the name of the serializable field
884 * @param val the value to assign to the field
885 * @throws IllegalArgumentException if <code>name</code> does not
886 * match the name of a serializable field for the class whose fields
887 * are being written, or if the type of the named field is not
888 * <code>boolean</code>
889 */
890 public abstract void put(String name, boolean val);
891
892 /**
893 * Put the value of the named byte field into the persistent field.
894 *
895 * @param name the name of the serializable field
896 * @param val the value to assign to the field
897 * @throws IllegalArgumentException if <code>name</code> does not
898 * match the name of a serializable field for the class whose fields
899 * are being written, or if the type of the named field is not
900 * <code>byte</code>
901 */
902 public abstract void put(String name, byte val);
903
904 /**
905 * Put the value of the named char field into the persistent field.
906 *
907 * @param name the name of the serializable field
908 * @param val the value to assign to the field
909 * @throws IllegalArgumentException if <code>name</code> does not
910 * match the name of a serializable field for the class whose fields
911 * are being written, or if the type of the named field is not
912 * <code>char</code>
913 */
914 public abstract void put(String name, char val);
915
916 /**
917 * Put the value of the named short field into the persistent field.
918 *
919 * @param name the name of the serializable field
920 * @param val the value to assign to the field
921 * @throws IllegalArgumentException if <code>name</code> does not
922 * match the name of a serializable field for the class whose fields
923 * are being written, or if the type of the named field is not
924 * <code>short</code>
925 */
926 public abstract void put(String name, short val);
927
928 /**
929 * Put the value of the named int field into the persistent field.
930 *
931 * @param name the name of the serializable field
932 * @param val the value to assign to the field
933 * @throws IllegalArgumentException if <code>name</code> does not
934 * match the name of a serializable field for the class whose fields
935 * are being written, or if the type of the named field is not
936 * <code>int</code>
937 */
938 public abstract void put(String name, int val);
939
940 /**
941 * Put the value of the named long field into the persistent field.
942 *
943 * @param name the name of the serializable field
944 * @param val the value to assign to the field
945 * @throws IllegalArgumentException if <code>name</code> does not
946 * match the name of a serializable field for the class whose fields
947 * are being written, or if the type of the named field is not
948 * <code>long</code>
949 */
950 public abstract void put(String name, long val);
951
952 /**
953 * Put the value of the named float field into the persistent field.
954 *
955 * @param name the name of the serializable field
956 * @param val the value to assign to the field
957 * @throws IllegalArgumentException if <code>name</code> does not
958 * match the name of a serializable field for the class whose fields
959 * are being written, or if the type of the named field is not
960 * <code>float</code>
961 */
962 public abstract void put(String name, float val);
963
964 /**
965 * Put the value of the named double field into the persistent field.
966 *
967 * @param name the name of the serializable field
968 * @param val the value to assign to the field
969 * @throws IllegalArgumentException if <code>name</code> does not
970 * match the name of a serializable field for the class whose fields
971 * are being written, or if the type of the named field is not
972 * <code>double</code>
973 */
974 public abstract void put(String name, double val);
975
976 /**
977 * Put the value of the named Object field into the persistent field.
978 *
979 * @param name the name of the serializable field
980 * @param val the value to assign to the field
981 * (which may be <code>null</code>)
982 * @throws IllegalArgumentException if <code>name</code> does not
983 * match the name of a serializable field for the class whose fields
984 * are being written, or if the type of the named field is not a
985 * reference type
986 */
987 public abstract void put(String name, Object val);
988
989 /**
990 * Write the data and fields to the specified ObjectOutput stream,
991 * which must be the same stream that produced this
992 * <code>PutField</code> object.
993 *
994 * @param out the stream to write the data and fields to
995 * @throws IOException if I/O errors occur while writing to the
996 * underlying stream
997 * @throws IllegalArgumentException if the specified stream is not
998 * the same stream that produced this <code>PutField</code>
999 * object
1000 * @deprecated This method does not write the values contained by this
1001 * <code>PutField</code> object in a proper format, and may
1002 * result in corruption of the serialization stream. The
1003 * correct way to write <code>PutField</code> data is by
1004 * calling the {@link java.io.ObjectOutputStream#writeFields()}
1005 * method.
1006 */
1007 @Deprecated
1008 public abstract void write(ObjectOutput out) throws IOException;
1009 }
1010
1011
1012 /**
1013 * Returns protocol version in use.
1014 */
1015 int getProtocolVersion() {
1016 return protocol;
1017 }
1018
1019 /**
1020 * Writes string without allowing it to be replaced in stream. Used by
1021 * ObjectStreamClass to write class descriptor type strings.
1022 */
1023 void writeTypeString(String str) throws IOException {
1024 int handle;
1025 if (str == null) {
1026 writeNull();
1027 } else if ((handle = handles.lookup(str)) != -1) {
1028 writeHandle(handle);
1029 } else {
1030 writeString(str, false);
1031 }
1032 }
1033
1034 /**
1035 * Verifies that this (possibly subclass) instance can be constructed
1036 * without violating security constraints: the subclass must not override
1037 * security-sensitive non-final methods, or else the
1038 * "enableSubclassImplementation" SerializablePermission is checked.
1039 */
1040 private void verifySubclass() {
1041 Class<?> cl = getClass();
1042 if (cl == ObjectOutputStream.class) {
1043 return;
1044 }
1045 SecurityManager sm = System.getSecurityManager();
1046 if (sm == null) {
1047 return;
1048 }
1049 processQueue(Caches.subclassAuditsQueue, Caches.subclassAudits);
1050 WeakClassKey key = new WeakClassKey(cl, Caches.subclassAuditsQueue);
1051 Boolean result = Caches.subclassAudits.get(key);
1052 if (result == null) {
1053 result = Boolean.valueOf(auditSubclass(cl));
1054 Caches.subclassAudits.putIfAbsent(key, result);
1055 }
1056 if (result.booleanValue()) {
1057 return;
1058 }
1059 sm.checkPermission(SUBCLASS_IMPLEMENTATION_PERMISSION);
1060 }
1061
1062 /**
1063 * Performs reflective checks on given subclass to verify that it doesn't
1064 * override security-sensitive non-final methods. Returns true if subclass
1065 * is "safe", false otherwise.
1066 */
1067 private static boolean auditSubclass(final Class<?> subcl) {
1068 Boolean result = AccessController.doPrivileged(
1069 new PrivilegedAction<Boolean>() {
1070 public Boolean run() {
1071 for (Class<?> cl = subcl;
1072 cl != ObjectOutputStream.class;
1073 cl = cl.getSuperclass())
1074 {
1075 try {
1076 cl.getDeclaredMethod(
1077 "writeUnshared", new Class<?>[] { Object.class });
1078 return Boolean.FALSE;
1079 } catch (NoSuchMethodException ex) {
1080 }
1081 try {
1082 cl.getDeclaredMethod("putFields", (Class<?>[]) null);
1083 return Boolean.FALSE;
1084 } catch (NoSuchMethodException ex) {
1085 }
1086 }
1087 return Boolean.TRUE;
1088 }
1089 }
1090 );
1091 return result.booleanValue();
1092 }
1093
1094 /**
1095 * Clears internal data structures.
1096 */
1097 private void clear() {
1098 subs.clear();
1099 handles.clear();
1100 }
1101
1102 /**
1103 * Underlying writeObject/writeUnshared implementation.
1104 */
1105 private void writeObject0(Object obj, boolean unshared)
1106 throws IOException
1107 {
1108 boolean oldMode = bout.setBlockDataMode(false);
1109 depth++;
1110 try {
1111 // handle previously written and non-replaceable objects
1112 int h;
1113 if ((obj = subs.lookup(obj)) == null) {
1114 writeNull();
1115 return;
1116 } else if (!unshared && (h = handles.lookup(obj)) != -1) {
1117 writeHandle(h);
1118 return;
1119 } else if (obj instanceof Class) {
1120 writeClass((Class) obj, unshared);
1121 return;
1122 } else if (obj instanceof ObjectStreamClass) {
1123 writeClassDesc((ObjectStreamClass) obj, unshared);
1124 return;
1125 }
1126
1127 // check for replacement object
1128 Object orig = obj;
1129 Class<?> cl = obj.getClass();
1130 ObjectStreamClass desc;
1131 for (;;) {
1132 // REMIND: skip this check for strings/arrays?
1133 Class<?> repCl;
1134 desc = ObjectStreamClass.lookup(cl, true);
1135 if (!desc.hasWriteReplaceMethod() ||
1136 (obj = desc.invokeWriteReplace(obj)) == null ||
1137 (repCl = obj.getClass()) == cl)
1138 {
1139 break;
1140 }
1141 cl = repCl;
1142 }
1143 if (enableReplace) {
1144 Object rep = replaceObject(obj);
1145 if (rep != obj && rep != null) {
1146 cl = rep.getClass();
1147 desc = ObjectStreamClass.lookup(cl, true);
1148 }
1149 obj = rep;
1150 }
1151
1152 // if object replaced, run through original checks a second time
1153 if (obj != orig) {
1154 subs.assign(orig, obj);
1155 if (obj == null) {
1156 writeNull();
1157 return;
1158 } else if (!unshared && (h = handles.lookup(obj)) != -1) {
1159 writeHandle(h);
1160 return;
1161 } else if (obj instanceof Class) {
1162 writeClass((Class) obj, unshared);
1163 return;
1164 } else if (obj instanceof ObjectStreamClass) {
1165 writeClassDesc((ObjectStreamClass) obj, unshared);
1166 return;
1167 }
1168 }
1169
1170 // remaining cases
1171 if (obj instanceof String) {
1172 writeString((String) obj, unshared);
1173 } else if (cl.isArray()) {
1174 writeArray(obj, desc, unshared);
1175 } else if (obj instanceof Enum) {
1176 writeEnum((Enum<?>) obj, desc, unshared);
1177 } else if (obj instanceof Serializable) {
1178 writeOrdinaryObject(obj, desc, unshared);
1179 } else {
1180 if (extendedDebugInfo) {
1181 throw new NotSerializableException(
1182 cl.getName() + "\n" + debugInfoStack.toString());
1183 } else {
1184 throw new NotSerializableException(cl.getName());
1185 }
1186 }
1187 } finally {
1188 depth--;
1189 bout.setBlockDataMode(oldMode);
1190 }
1191 }
1192
1193 /**
1194 * Writes null code to stream.
1195 */
1196 private void writeNull() throws IOException {
1197 bout.writeByte(TC_NULL);
1198 }
1199
1200 /**
1201 * Writes given object handle to stream.
1202 */
1203 private void writeHandle(int handle) throws IOException {
1204 bout.writeByte(TC_REFERENCE);
1205 bout.writeInt(baseWireHandle + handle);
1206 }
1207
1208 /**
1209 * Writes representation of given class to stream.
1210 */
1211 private void writeClass(Class<?> cl, boolean unshared) throws IOException {
1212 bout.writeByte(TC_CLASS);
1213 writeClassDesc(ObjectStreamClass.lookup(cl, true), false);
1214 handles.assign(unshared ? null : cl);
1215 }
1216
1217 /**
1218 * Writes representation of given class descriptor to stream.
1219 */
1220 private void writeClassDesc(ObjectStreamClass desc, boolean unshared)
1221 throws IOException
1222 {
1223 int handle;
1224 if (desc == null) {
1225 writeNull();
1226 } else if (!unshared && (handle = handles.lookup(desc)) != -1) {
1227 writeHandle(handle);
1228 } else if (desc.isProxy()) {
1229 writeProxyDesc(desc, unshared);
1230 } else {
1231 writeNonProxyDesc(desc, unshared);
1232 }
1233 }
1234
1235 private boolean isCustomSubclass() {
1236 // Return true if this class is a custom subclass of ObjectOutputStream
1237 return getClass().getClassLoader()
1238 != ObjectOutputStream.class.getClassLoader();
1239 }
1240
1241 /**
1242 * Writes class descriptor representing a dynamic proxy class to stream.
1243 */
1244 private void writeProxyDesc(ObjectStreamClass desc, boolean unshared)
1245 throws IOException
1246 {
1247 bout.writeByte(TC_PROXYCLASSDESC);
1248 handles.assign(unshared ? null : desc);
1249
1250 Class<?> cl = desc.forClass();
1251 Class<?>[] ifaces = cl.getInterfaces();
1252 bout.writeInt(ifaces.length);
1253 for (int i = 0; i < ifaces.length; i++) {
1254 bout.writeUTF(ifaces[i].getName());
1255 }
1256
1257 bout.setBlockDataMode(true);
1258 if (cl != null && isCustomSubclass()) {
1259 ReflectUtil.checkPackageAccess(cl);
1260 }
1261 annotateProxyClass(cl);
1262 bout.setBlockDataMode(false);
1263 bout.writeByte(TC_ENDBLOCKDATA);
1264
1265 writeClassDesc(desc.getSuperDesc(), false);
1266 }
1267
1268 /**
1269 * Writes class descriptor representing a standard (i.e., not a dynamic
1270 * proxy) class to stream.
1271 */
1272 private void writeNonProxyDesc(ObjectStreamClass desc, boolean unshared)
1273 throws IOException
1274 {
1275 bout.writeByte(TC_CLASSDESC);
1276 handles.assign(unshared ? null : desc);
1277
1278 if (protocol == PROTOCOL_VERSION_1) {
1279 // do not invoke class descriptor write hook with old protocol
1280 desc.writeNonProxy(this);
1281 } else {
1282 writeClassDescriptor(desc);
1283 }
1284
1285 Class<?> cl = desc.forClass();
1286 bout.setBlockDataMode(true);
1287 if (cl != null && isCustomSubclass()) {
1288 ReflectUtil.checkPackageAccess(cl);
1289 }
1290 annotateClass(cl);
1291 bout.setBlockDataMode(false);
1292 bout.writeByte(TC_ENDBLOCKDATA);
1293
1294 writeClassDesc(desc.getSuperDesc(), false);
1295 }
1296
1297 /**
1298 * Writes given string to stream, using standard or long UTF format
1299 * depending on string length.
1300 */
1301 private void writeString(String str, boolean unshared) throws IOException {
1302 handles.assign(unshared ? null : str);
1303 long utflen = bout.getUTFLength(str);
1304 if (utflen <= 0xFFFF) {
1305 bout.writeByte(TC_STRING);
1306 bout.writeUTF(str, utflen);
1307 } else {
1308 bout.writeByte(TC_LONGSTRING);
1309 bout.writeLongUTF(str, utflen);
1310 }
1311 }
1312
1313 /**
1314 * Writes given array object to stream.
1315 */
1316 private void writeArray(Object array,
1317 ObjectStreamClass desc,
1318 boolean unshared)
1319 throws IOException
1320 {
1321 bout.writeByte(TC_ARRAY);
1322 writeClassDesc(desc, false);
1323 handles.assign(unshared ? null : array);
1324
1325 Class<?> ccl = desc.forClass().getComponentType();
1326 if (ccl.isPrimitive()) {
1327 if (ccl == Integer.TYPE) {
1328 int[] ia = (int[]) array;
1329 bout.writeInt(ia.length);
1330 bout.writeInts(ia, 0, ia.length);
1331 } else if (ccl == Byte.TYPE) {
1332 byte[] ba = (byte[]) array;
1333 bout.writeInt(ba.length);
1334 bout.write(ba, 0, ba.length, true);
1335 } else if (ccl == Long.TYPE) {
1336 long[] ja = (long[]) array;
1337 bout.writeInt(ja.length);
1338 bout.writeLongs(ja, 0, ja.length);
1339 } else if (ccl == Float.TYPE) {
1340 float[] fa = (float[]) array;
1341 bout.writeInt(fa.length);
1342 bout.writeFloats(fa, 0, fa.length);
1343 } else if (ccl == Double.TYPE) {
1344 double[] da = (double[]) array;
1345 bout.writeInt(da.length);
1346 bout.writeDoubles(da, 0, da.length);
1347 } else if (ccl == Short.TYPE) {
1348 short[] sa = (short[]) array;
1349 bout.writeInt(sa.length);
1350 bout.writeShorts(sa, 0, sa.length);
1351 } else if (ccl == Character.TYPE) {
1352 char[] ca = (char[]) array;
1353 bout.writeInt(ca.length);
1354 bout.writeChars(ca, 0, ca.length);
1355 } else if (ccl == Boolean.TYPE) {
1356 boolean[] za = (boolean[]) array;
1357 bout.writeInt(za.length);
1358 bout.writeBooleans(za, 0, za.length);
1359 } else {
1360 throw new InternalError();
1361 }
1362 } else {
1363 Object[] objs = (Object[]) array;
1364 int len = objs.length;
1365 bout.writeInt(len);
1366 if (extendedDebugInfo) {
1367 debugInfoStack.push(
1368 "array (class \"" + array.getClass().getName() +
1369 "\", size: " + len + ")");
1370 }
1371 try {
1372 for (int i = 0; i < len; i++) {
1373 if (extendedDebugInfo) {
1374 debugInfoStack.push(
1375 "element of array (index: " + i + ")");
1376 }
1377 try {
1378 writeObject0(objs[i], false);
1379 } finally {
1380 if (extendedDebugInfo) {
1381 debugInfoStack.pop();
1382 }
1383 }
1384 }
1385 } finally {
1386 if (extendedDebugInfo) {
1387 debugInfoStack.pop();
1388 }
1389 }
1390 }
1391 }
1392
1393 /**
1394 * Writes given enum constant to stream.
1395 */
1396 private void writeEnum(Enum<?> en,
1397 ObjectStreamClass desc,
1398 boolean unshared)
1399 throws IOException
1400 {
1401 bout.writeByte(TC_ENUM);
1402 ObjectStreamClass sdesc = desc.getSuperDesc();
1403 writeClassDesc((sdesc.forClass() == Enum.class) ? desc : sdesc, false);
1404 handles.assign(unshared ? null : en);
1405 writeString(en.name(), false);
1406 }
1407
1408 /**
1409 * Writes representation of a "ordinary" (i.e., not a String, Class,
1410 * ObjectStreamClass, array, or enum constant) serializable object to the
1411 * stream.
1412 */
1413 private void writeOrdinaryObject(Object obj,
1414 ObjectStreamClass desc,
1415 boolean unshared)
1416 throws IOException
1417 {
1418 if (extendedDebugInfo) {
1419 debugInfoStack.push(
1420 (depth == 1 ? "root " : "") + "object (class \"" +
1421 obj.getClass().getName() + "\", " + obj.toString() + ")");
1422 }
1423 try {
1424 desc.checkSerialize();
1425
1426 bout.writeByte(TC_OBJECT);
1427 writeClassDesc(desc, false);
1428 handles.assign(unshared ? null : obj);
1429 if (desc.isExternalizable() && !desc.isProxy()) {
1430 writeExternalData((Externalizable) obj);
1431 } else {
1432 writeSerialData(obj, desc);
1433 }
1434 } finally {
1435 if (extendedDebugInfo) {
1436 debugInfoStack.pop();
1437 }
1438 }
1439 }
1440
1441 /**
1442 * Writes externalizable data of given object by invoking its
1443 * writeExternal() method.
1444 */
1445 private void writeExternalData(Externalizable obj) throws IOException {
1446 PutFieldImpl oldPut = curPut;
1447 curPut = null;
1448
1449 if (extendedDebugInfo) {
1450 debugInfoStack.push("writeExternal data");
1451 }
1452 SerialCallbackContext oldContext = curContext;
1453 try {
1454 curContext = null;
1455 if (protocol == PROTOCOL_VERSION_1) {
1456 obj.writeExternal(this);
1457 } else {
1458 bout.setBlockDataMode(true);
1459 obj.writeExternal(this);
1460 bout.setBlockDataMode(false);
1461 bout.writeByte(TC_ENDBLOCKDATA);
1462 }
1463 } finally {
1464 curContext = oldContext;
1465 if (extendedDebugInfo) {
1466 debugInfoStack.pop();
1467 }
1468 }
1469
1470 curPut = oldPut;
1471 }
1472
1473 /**
1474 * Writes instance data for each serializable class of given object, from
1475 * superclass to subclass.
1476 */
1477 private void writeSerialData(Object obj, ObjectStreamClass desc)
1478 throws IOException
1479 {
1480 ObjectStreamClass.ClassDataSlot[] slots = desc.getClassDataLayout();
1481 for (int i = 0; i < slots.length; i++) {
1482 ObjectStreamClass slotDesc = slots[i].desc;
1483 if (slotDesc.hasWriteObjectMethod()) {
1484 PutFieldImpl oldPut = curPut;
1485 curPut = null;
1486 SerialCallbackContext oldContext = curContext;
1487
1488 if (extendedDebugInfo) {
1489 debugInfoStack.push(
1490 "custom writeObject data (class \"" +
1491 slotDesc.getName() + "\")");
1492 }
1493 try {
1494 curContext = new SerialCallbackContext(obj, slotDesc);
1495 bout.setBlockDataMode(true);
1496 slotDesc.invokeWriteObject(obj, this);
1497 bout.setBlockDataMode(false);
1498 bout.writeByte(TC_ENDBLOCKDATA);
1499 } finally {
1500 curContext.setUsed();
1501 curContext = oldContext;
1502 if (extendedDebugInfo) {
1503 debugInfoStack.pop();
1504 }
1505 }
1506
1507 curPut = oldPut;
1508 } else {
1509 defaultWriteFields(obj, slotDesc);
1510 }
1511 }
1512 }
1513
1514 /**
1515 * Fetches and writes values of serializable fields of given object to
1516 * stream. The given class descriptor specifies which field values to
1517 * write, and in which order they should be written.
1518 */
1519 private void defaultWriteFields(Object obj, ObjectStreamClass desc)
1520 throws IOException
1521 {
1522 Class<?> cl = desc.forClass();
1523 if (cl != null && obj != null && !cl.isInstance(obj)) {
1524 throw new ClassCastException();
1525 }
1526
1527 desc.checkDefaultSerialize();
1528
1529 int primDataSize = desc.getPrimDataSize();
1530 if (primDataSize > 0) {
1531 if (primVals == null || primVals.length < primDataSize) {
1532 primVals = new byte[primDataSize];
1533 }
1534 desc.getPrimFieldValues(obj, primVals);
1535 bout.write(primVals, 0, primDataSize, false);
1536 }
1537
1538 int numObjFields = desc.getNumObjFields();
1539 if (numObjFields > 0) {
1540 ObjectStreamField[] fields = desc.getFields(false);
1541 Object[] objVals = new Object[numObjFields];
1542 int numPrimFields = fields.length - objVals.length;
1543 desc.getObjFieldValues(obj, objVals);
1544 for (int i = 0; i < objVals.length; i++) {
1545 if (extendedDebugInfo) {
1546 debugInfoStack.push(
1547 "field (class \"" + desc.getName() + "\", name: \"" +
1548 fields[numPrimFields + i].getName() + "\", type: \"" +
1549 fields[numPrimFields + i].getType() + "\")");
1550 }
1551 try {
1552 writeObject0(objVals[i],
1553 fields[numPrimFields + i].isUnshared());
1554 } finally {
1555 if (extendedDebugInfo) {
1556 debugInfoStack.pop();
1557 }
1558 }
1559 }
1560 }
1561 }
1562
1563 /**
1564 * Attempts to write to stream fatal IOException that has caused
1565 * serialization to abort.
1566 */
1567 private void writeFatalException(IOException ex) throws IOException {
1568 /*
1569 * Note: the serialization specification states that if a second
1570 * IOException occurs while attempting to serialize the original fatal
1571 * exception to the stream, then a StreamCorruptedException should be
1572 * thrown (section 2.1). However, due to a bug in previous
1573 * implementations of serialization, StreamCorruptedExceptions were
1574 * rarely (if ever) actually thrown--the "root" exceptions from
1575 * underlying streams were thrown instead. This historical behavior is
1576 * followed here for consistency.
1577 */
1578 clear();
1579 boolean oldMode = bout.setBlockDataMode(false);
1580 try {
1581 bout.writeByte(TC_EXCEPTION);
1582 writeObject0(ex, false);
1583 clear();
1584 } finally {
1585 bout.setBlockDataMode(oldMode);
1586 }
1587 }
1588
1589 /**
1590 * Converts specified span of float values into byte values.
1591 */
1592 // REMIND: remove once hotspot inlines Float.floatToIntBits
1593 private static native void floatsToBytes(float[] src, int srcpos,
1594 byte[] dst, int dstpos,
1595 int nfloats);
1596
1597 /**
1598 * Converts specified span of double values into byte values.
1599 */
1600 // REMIND: remove once hotspot inlines Double.doubleToLongBits
1601 private static native void doublesToBytes(double[] src, int srcpos,
1602 byte[] dst, int dstpos,
1603 int ndoubles);
1604
1605 /**
1606 * Default PutField implementation.
1607 */
1608 private class PutFieldImpl extends PutField {
1609
1610 /** class descriptor describing serializable fields */
1611 private final ObjectStreamClass desc;
1612 /** primitive field values */
1613 private final byte[] primVals;
1614 /** object field values */
1615 private final Object[] objVals;
1616
1617 /**
1618 * Creates PutFieldImpl object for writing fields defined in given
1619 * class descriptor.
1620 */
1621 PutFieldImpl(ObjectStreamClass desc) {
1622 this.desc = desc;
1623 primVals = new byte[desc.getPrimDataSize()];
1624 objVals = new Object[desc.getNumObjFields()];
1625 }
1626
1627 public void put(String name, boolean val) {
1628 Bits.putBoolean(primVals, getFieldOffset(name, Boolean.TYPE), val);
1629 }
1630
1631 public void put(String name, byte val) {
1632 primVals[getFieldOffset(name, Byte.TYPE)] = val;
1633 }
1634
1635 public void put(String name, char val) {
1636 Bits.putChar(primVals, getFieldOffset(name, Character.TYPE), val);
1637 }
1638
1639 public void put(String name, short val) {
1640 Bits.putShort(primVals, getFieldOffset(name, Short.TYPE), val);
1641 }
1642
1643 public void put(String name, int val) {
1644 Bits.putInt(primVals, getFieldOffset(name, Integer.TYPE), val);
1645 }
1646
1647 public void put(String name, float val) {
1648 Bits.putFloat(primVals, getFieldOffset(name, Float.TYPE), val);
1649 }
1650
1651 public void put(String name, long val) {
1652 Bits.putLong(primVals, getFieldOffset(name, Long.TYPE), val);
1653 }
1654
1655 public void put(String name, double val) {
1656 Bits.putDouble(primVals, getFieldOffset(name, Double.TYPE), val);
1657 }
1658
1659 public void put(String name, Object val) {
1660 objVals[getFieldOffset(name, Object.class)] = val;
1661 }
1662
1663 // deprecated in ObjectOutputStream.PutField
1664 public void write(ObjectOutput out) throws IOException {
1665 /*
1666 * Applications should *not* use this method to write PutField
1667 * data, as it will lead to stream corruption if the PutField
1668 * object writes any primitive data (since block data mode is not
1669 * unset/set properly, as is done in OOS.writeFields()). This
1670 * broken implementation is being retained solely for behavioral
1671 * compatibility, in order to support applications which use
1672 * OOS.PutField.write() for writing only non-primitive data.
1673 *
1674 * Serialization of unshared objects is not implemented here since
1675 * it is not necessary for backwards compatibility; also, unshared
1676 * semantics may not be supported by the given ObjectOutput
1677 * instance. Applications which write unshared objects using the
1678 * PutField API must use OOS.writeFields().
1679 */
1680 if (ObjectOutputStream.this != out) {
1681 throw new IllegalArgumentException("wrong stream");
1682 }
1683 out.write(primVals, 0, primVals.length);
1684
1685 ObjectStreamField[] fields = desc.getFields(false);
1686 int numPrimFields = fields.length - objVals.length;
1687 // REMIND: warn if numPrimFields > 0?
1688 for (int i = 0; i < objVals.length; i++) {
1689 if (fields[numPrimFields + i].isUnshared()) {
1690 throw new IOException("cannot write unshared object");
1691 }
1692 out.writeObject(objVals[i]);
1693 }
1694 }
1695
1696 /**
1697 * Writes buffered primitive data and object fields to stream.
1698 */
1699 void writeFields() throws IOException {
1700 bout.write(primVals, 0, primVals.length, false);
1701
1702 ObjectStreamField[] fields = desc.getFields(false);
1703 int numPrimFields = fields.length - objVals.length;
1704 for (int i = 0; i < objVals.length; i++) {
1705 if (extendedDebugInfo) {
1706 debugInfoStack.push(
1707 "field (class \"" + desc.getName() + "\", name: \"" +
1708 fields[numPrimFields + i].getName() + "\", type: \"" +
1709 fields[numPrimFields + i].getType() + "\")");
1710 }
1711 try {
1712 writeObject0(objVals[i],
1713 fields[numPrimFields + i].isUnshared());
1714 } finally {
1715 if (extendedDebugInfo) {
1716 debugInfoStack.pop();
1717 }
1718 }
1719 }
1720 }
1721
1722 /**
1723 * Returns offset of field with given name and type. A specified type
1724 * of null matches all types, Object.class matches all non-primitive
1725 * types, and any other non-null type matches assignable types only.
1726 * Throws IllegalArgumentException if no matching field found.
1727 */
1728 private int getFieldOffset(String name, Class<?> type) {
1729 ObjectStreamField field = desc.getField(name, type);
1730 if (field == null) {
1731 throw new IllegalArgumentException("no such field " + name +
1732 " with type " + type);
1733 }
1734 return field.getOffset();
1735 }
1736 }
1737
1738 /**
1739 * Buffered output stream with two modes: in default mode, outputs data in
1740 * same format as DataOutputStream; in "block data" mode, outputs data
1741 * bracketed by block data markers (see object serialization specification
1742 * for details).
1743 */
1744 private static class BlockDataOutputStream
1745 extends OutputStream implements DataOutput
1746 {
1747 /** maximum data block length */
1748 private static final int MAX_BLOCK_SIZE = 1024;
1749 /** maximum data block header length */
1750 private static final int MAX_HEADER_SIZE = 5;
1751 /** (tunable) length of char buffer (for writing strings) */
1752 private static final int CHAR_BUF_SIZE = 256;
1753
1754 /** buffer for writing general/block data */
1755 private final byte[] buf = new byte[MAX_BLOCK_SIZE];
1756 /** buffer for writing block data headers */
1757 private final byte[] hbuf = new byte[MAX_HEADER_SIZE];
1758 /** char buffer for fast string writes */
1759 private final char[] cbuf = new char[CHAR_BUF_SIZE];
1760
1761 /** block data mode */
1762 private boolean blkmode = false;
1763 /** current offset into buf */
1764 private int pos = 0;
1765
1766 /** underlying output stream */
1767 private final OutputStream out;
1768 /** loopback stream (for data writes that span data blocks) */
1769 private final DataOutputStream dout;
1770
1771 /**
1772 * Creates new BlockDataOutputStream on top of given underlying stream.
1773 * Block data mode is turned off by default.
1774 */
1775 BlockDataOutputStream(OutputStream out) {
1776 this.out = out;
1777 dout = new DataOutputStream(this);
1778 }
1779
1780 /**
1781 * Sets block data mode to the given mode (true == on, false == off)
1782 * and returns the previous mode value. If the new mode is the same as
1783 * the old mode, no action is taken. If the new mode differs from the
1784 * old mode, any buffered data is flushed before switching to the new
1785 * mode.
1786 */
1787 boolean setBlockDataMode(boolean mode) throws IOException {
1788 if (blkmode == mode) {
1789 return blkmode;
1790 }
1791 drain();
1792 blkmode = mode;
1793 return !blkmode;
1794 }
1795
1796 /**
1797 * Returns true if the stream is currently in block data mode, false
1798 * otherwise.
1799 */
1800 boolean getBlockDataMode() {
1801 return blkmode;
1802 }
1803
1804 /* ----------------- generic output stream methods ----------------- */
1805 /*
1806 * The following methods are equivalent to their counterparts in
1807 * OutputStream, except that they partition written data into data
1808 * blocks when in block data mode.
1809 */
1810
1811 public void write(int b) throws IOException {
1812 if (pos >= MAX_BLOCK_SIZE) {
1813 drain();
1814 }
1815 buf[pos++] = (byte) b;
1816 }
1817
1818 public void write(byte[] b) throws IOException {
1819 write(b, 0, b.length, false);
1820 }
1821
1822 public void write(byte[] b, int off, int len) throws IOException {
1823 write(b, off, len, false);
1824 }
1825
1826 public void flush() throws IOException {
1827 drain();
1828 out.flush();
1829 }
1830
1831 public void close() throws IOException {
1832 flush();
1833 out.close();
1834 }
1835
1836 /**
1837 * Writes specified span of byte values from given array. If copy is
1838 * true, copies the values to an intermediate buffer before writing
1839 * them to underlying stream (to avoid exposing a reference to the
1840 * original byte array).
1841 */
1842 void write(byte[] b, int off, int len, boolean copy)
1843 throws IOException
1844 {
1845 if (!(copy || blkmode)) { // write directly
1846 drain();
1847 out.write(b, off, len);
1848 return;
1849 }
1850
1851 while (len > 0) {
1852 if (pos >= MAX_BLOCK_SIZE) {
1853 drain();
1854 }
1855 if (len >= MAX_BLOCK_SIZE && !copy && pos == 0) {
1856 // avoid unnecessary copy
1857 writeBlockHeader(MAX_BLOCK_SIZE);
1858 out.write(b, off, MAX_BLOCK_SIZE);
1859 off += MAX_BLOCK_SIZE;
1860 len -= MAX_BLOCK_SIZE;
1861 } else {
1862 int wlen = Math.min(len, MAX_BLOCK_SIZE - pos);
1863 System.arraycopy(b, off, buf, pos, wlen);
1864 pos += wlen;
1865 off += wlen;
1866 len -= wlen;
1867 }
1868 }
1869 }
1870
1871 /**
1872 * Writes all buffered data from this stream to the underlying stream,
1873 * but does not flush underlying stream.
1874 */
1875 void drain() throws IOException {
1876 if (pos == 0) {
1877 return;
1878 }
1879 if (blkmode) {
1880 writeBlockHeader(pos);
1881 }
1882 out.write(buf, 0, pos);
1883 pos = 0;
1884 }
1885
1886 /**
1887 * Writes block data header. Data blocks shorter than 256 bytes are
1888 * prefixed with a 2-byte header; all others start with a 5-byte
1889 * header.
1890 */
1891 private void writeBlockHeader(int len) throws IOException {
1892 if (len <= 0xFF) {
1893 hbuf[0] = TC_BLOCKDATA;
1894 hbuf[1] = (byte) len;
1895 out.write(hbuf, 0, 2);
1896 } else {
1897 hbuf[0] = TC_BLOCKDATALONG;
1898 Bits.putInt(hbuf, 1, len);
1899 out.write(hbuf, 0, 5);
1900 }
1901 }
1902
1903
1904 /* ----------------- primitive data output methods ----------------- */
1905 /*
1906 * The following methods are equivalent to their counterparts in
1907 * DataOutputStream, except that they partition written data into data
1908 * blocks when in block data mode.
1909 */
1910
1911 public void writeBoolean(boolean v) throws IOException {
1912 if (pos >= MAX_BLOCK_SIZE) {
1913 drain();
1914 }
1915 Bits.putBoolean(buf, pos++, v);
1916 }
1917
1918 public void writeByte(int v) throws IOException {
1919 if (pos >= MAX_BLOCK_SIZE) {
1920 drain();
1921 }
1922 buf[pos++] = (byte) v;
1923 }
1924
1925 public void writeChar(int v) throws IOException {
1926 if (pos + 2 <= MAX_BLOCK_SIZE) {
1927 Bits.putChar(buf, pos, (char) v);
1928 pos += 2;
1929 } else {
1930 dout.writeChar(v);
1931 }
1932 }
1933
1934 public void writeShort(int v) throws IOException {
1935 if (pos + 2 <= MAX_BLOCK_SIZE) {
1936 Bits.putShort(buf, pos, (short) v);
1937 pos += 2;
1938 } else {
1939 dout.writeShort(v);
1940 }
1941 }
1942
1943 public void writeInt(int v) throws IOException {
1944 if (pos + 4 <= MAX_BLOCK_SIZE) {
1945 Bits.putInt(buf, pos, v);
1946 pos += 4;
1947 } else {
1948 dout.writeInt(v);
1949 }
1950 }
1951
1952 public void writeFloat(float v) throws IOException {
1953 if (pos + 4 <= MAX_BLOCK_SIZE) {
1954 Bits.putFloat(buf, pos, v);
1955 pos += 4;
1956 } else {
1957 dout.writeFloat(v);
1958 }
1959 }
1960
1961 public void writeLong(long v) throws IOException {
1962 if (pos + 8 <= MAX_BLOCK_SIZE) {
1963 Bits.putLong(buf, pos, v);
1964 pos += 8;
1965 } else {
1966 dout.writeLong(v);
1967 }
1968 }
1969
1970 public void writeDouble(double v) throws IOException {
1971 if (pos + 8 <= MAX_BLOCK_SIZE) {
1972 Bits.putDouble(buf, pos, v);
1973 pos += 8;
1974 } else {
1975 dout.writeDouble(v);
1976 }
1977 }
1978
1979 public void writeBytes(String s) throws IOException {
1980 int endoff = s.length();
1981 int cpos = 0;
1982 int csize = 0;
1983 for (int off = 0; off < endoff; ) {
1984 if (cpos >= csize) {
1985 cpos = 0;
1986 csize = Math.min(endoff - off, CHAR_BUF_SIZE);
1987 s.getChars(off, off + csize, cbuf, 0);
1988 }
1989 if (pos >= MAX_BLOCK_SIZE) {
1990 drain();
1991 }
1992 int n = Math.min(csize - cpos, MAX_BLOCK_SIZE - pos);
1993 int stop = pos + n;
1994 while (pos < stop) {
1995 buf[pos++] = (byte) cbuf[cpos++];
1996 }
1997 off += n;
1998 }
1999 }
2000
2001 public void writeChars(String s) throws IOException {
2002 int endoff = s.length();
2003 for (int off = 0; off < endoff; ) {
2004 int csize = Math.min(endoff - off, CHAR_BUF_SIZE);
2005 s.getChars(off, off + csize, cbuf, 0);
2006 writeChars(cbuf, 0, csize);
2007 off += csize;
2008 }
2009 }
2010
2011 public void writeUTF(String s) throws IOException {
2012 writeUTF(s, getUTFLength(s));
2013 }
2014
2015
2016 /* -------------- primitive data array output methods -------------- */
2017 /*
2018 * The following methods write out spans of primitive data values.
2019 * Though equivalent to calling the corresponding primitive write
2020 * methods repeatedly, these methods are optimized for writing groups
2021 * of primitive data values more efficiently.
2022 */
2023
2024 void writeBooleans(boolean[] v, int off, int len) throws IOException {
2025 int endoff = off + len;
2026 while (off < endoff) {
2027 if (pos >= MAX_BLOCK_SIZE) {
2028 drain();
2029 }
2030 int stop = Math.min(endoff, off + (MAX_BLOCK_SIZE - pos));
2031 while (off < stop) {
2032 Bits.putBoolean(buf, pos++, v[off++]);
2033 }
2034 }
2035 }
2036
2037 void writeChars(char[] v, int off, int len) throws IOException {
2038 int limit = MAX_BLOCK_SIZE - 2;
2039 int endoff = off + len;
2040 while (off < endoff) {
2041 if (pos <= limit) {
2042 int avail = (MAX_BLOCK_SIZE - pos) >> 1;
2043 int stop = Math.min(endoff, off + avail);
2044 while (off < stop) {
2045 Bits.putChar(buf, pos, v[off++]);
2046 pos += 2;
2047 }
2048 } else {
2049 dout.writeChar(v[off++]);
2050 }
2051 }
2052 }
2053
2054 void writeShorts(short[] v, int off, int len) throws IOException {
2055 int limit = MAX_BLOCK_SIZE - 2;
2056 int endoff = off + len;
2057 while (off < endoff) {
2058 if (pos <= limit) {
2059 int avail = (MAX_BLOCK_SIZE - pos) >> 1;
2060 int stop = Math.min(endoff, off + avail);
2061 while (off < stop) {
2062 Bits.putShort(buf, pos, v[off++]);
2063 pos += 2;
2064 }
2065 } else {
2066 dout.writeShort(v[off++]);
2067 }
2068 }
2069 }
2070
2071 void writeInts(int[] v, int off, int len) throws IOException {
2072 int limit = MAX_BLOCK_SIZE - 4;
2073 int endoff = off + len;
2074 while (off < endoff) {
2075 if (pos <= limit) {
2076 int avail = (MAX_BLOCK_SIZE - pos) >> 2;
2077 int stop = Math.min(endoff, off + avail);
2078 while (off < stop) {
2079 Bits.putInt(buf, pos, v[off++]);
2080 pos += 4;
2081 }
2082 } else {
2083 dout.writeInt(v[off++]);
2084 }
2085 }
2086 }
2087
2088 void writeFloats(float[] v, int off, int len) throws IOException {
2089 int limit = MAX_BLOCK_SIZE - 4;
2090 int endoff = off + len;
2091 while (off < endoff) {
2092 if (pos <= limit) {
2093 int avail = (MAX_BLOCK_SIZE - pos) >> 2;
2094 int chunklen = Math.min(endoff - off, avail);
2095 floatsToBytes(v, off, buf, pos, chunklen);
2096 off += chunklen;
2097 pos += chunklen << 2;
2098 } else {
2099 dout.writeFloat(v[off++]);
2100 }
2101 }
2102 }
2103
2104 void writeLongs(long[] v, int off, int len) throws IOException {
2105 int limit = MAX_BLOCK_SIZE - 8;
2106 int endoff = off + len;
2107 while (off < endoff) {
2108 if (pos <= limit) {
2109 int avail = (MAX_BLOCK_SIZE - pos) >> 3;
2110 int stop = Math.min(endoff, off + avail);
2111 while (off < stop) {
2112 Bits.putLong(buf, pos, v[off++]);
2113 pos += 8;
2114 }
2115 } else {
2116 dout.writeLong(v[off++]);
2117 }
2118 }
2119 }
2120
2121 void writeDoubles(double[] v, int off, int len) throws IOException {
2122 int limit = MAX_BLOCK_SIZE - 8;
2123 int endoff = off + len;
2124 while (off < endoff) {
2125 if (pos <= limit) {
2126 int avail = (MAX_BLOCK_SIZE - pos) >> 3;
2127 int chunklen = Math.min(endoff - off, avail);
2128 doublesToBytes(v, off, buf, pos, chunklen);
2129 off += chunklen;
2130 pos += chunklen << 3;
2131 } else {
2132 dout.writeDouble(v[off++]);
2133 }
2134 }
2135 }
2136
2137 /**
2138 * Returns the length in bytes of the UTF encoding of the given string.
2139 */
2140 long getUTFLength(String s) {
2141 int len = s.length();
2142 long utflen = 0;
2143 for (int off = 0; off < len; ) {
2144 int csize = Math.min(len - off, CHAR_BUF_SIZE);
2145 s.getChars(off, off + csize, cbuf, 0);
2146 for (int cpos = 0; cpos < csize; cpos++) {
2147 char c = cbuf[cpos];
2148 if (c >= 0x0001 && c <= 0x007F) {
2149 utflen++;
2150 } else if (c > 0x07FF) {
2151 utflen += 3;
2152 } else {
2153 utflen += 2;
2154 }
2155 }
2156 off += csize;
2157 }
2158 return utflen;
2159 }
2160
2161 /**
2162 * Writes the given string in UTF format. This method is used in
2163 * situations where the UTF encoding length of the string is already
2164 * known; specifying it explicitly avoids a prescan of the string to
2165 * determine its UTF length.
2166 */
2167 void writeUTF(String s, long utflen) throws IOException {
2168 if (utflen > 0xFFFFL) {
2169 throw new UTFDataFormatException();
2170 }
2171 writeShort((int) utflen);
2172 if (utflen == (long) s.length()) {
2173 writeBytes(s);
2174 } else {
2175 writeUTFBody(s);
2176 }
2177 }
2178
2179 /**
2180 * Writes given string in "long" UTF format. "Long" UTF format is
2181 * identical to standard UTF, except that it uses an 8 byte header
2182 * (instead of the standard 2 bytes) to convey the UTF encoding length.
2183 */
2184 void writeLongUTF(String s) throws IOException {
2185 writeLongUTF(s, getUTFLength(s));
2186 }
2187
2188 /**
2189 * Writes given string in "long" UTF format, where the UTF encoding
2190 * length of the string is already known.
2191 */
2192 void writeLongUTF(String s, long utflen) throws IOException {
2193 writeLong(utflen);
2194 if (utflen == (long) s.length()) {
2195 writeBytes(s);
2196 } else {
2197 writeUTFBody(s);
2198 }
2199 }
2200
2201 /**
2202 * Writes the "body" (i.e., the UTF representation minus the 2-byte or
2203 * 8-byte length header) of the UTF encoding for the given string.
2204 */
2205 private void writeUTFBody(String s) throws IOException {
2206 int limit = MAX_BLOCK_SIZE - 3;
2207 int len = s.length();
2208 for (int off = 0; off < len; ) {
2209 int csize = Math.min(len - off, CHAR_BUF_SIZE);
2210 s.getChars(off, off + csize, cbuf, 0);
2211 for (int cpos = 0; cpos < csize; cpos++) {
2212 char c = cbuf[cpos];
2213 if (pos <= limit) {
2214 if (c <= 0x007F && c != 0) {
2215 buf[pos++] = (byte) c;
2216 } else if (c > 0x07FF) {
2217 buf[pos + 2] = (byte) (0x80 | ((c >> 0) & 0x3F));
2218 buf[pos + 1] = (byte) (0x80 | ((c >> 6) & 0x3F));
2219 buf[pos + 0] = (byte) (0xE0 | ((c >> 12) & 0x0F));
2220 pos += 3;
2221 } else {
2222 buf[pos + 1] = (byte) (0x80 | ((c >> 0) & 0x3F));
2223 buf[pos + 0] = (byte) (0xC0 | ((c >> 6) & 0x1F));
2224 pos += 2;
2225 }
2226 } else { // write one byte at a time to normalize block
2227 if (c <= 0x007F && c != 0) {
2228 write(c);
2229 } else if (c > 0x07FF) {
2230 write(0xE0 | ((c >> 12) & 0x0F));
2231 write(0x80 | ((c >> 6) & 0x3F));
2232 write(0x80 | ((c >> 0) & 0x3F));
2233 } else {
2234 write(0xC0 | ((c >> 6) & 0x1F));
2235 write(0x80 | ((c >> 0) & 0x3F));
2236 }
2237 }
2238 }
2239 off += csize;
2240 }
2241 }
2242 }
2243
2244 /**
2245 * Lightweight identity hash table which maps objects to integer handles,
2246 * assigned in ascending order.
2247 */
2248 private static class HandleTable {
2249
2250 /* number of mappings in table/next available handle */
2251 private int size;
2252 /* size threshold determining when to expand hash spine */
2253 private int threshold;
2254 /* factor for computing size threshold */
2255 private final float loadFactor;
2256 /* maps hash value -> candidate handle value */
2257 private int[] spine;
2258 /* maps handle value -> next candidate handle value */
2259 private int[] next;
2260 /* maps handle value -> associated object */
2261 private Object[] objs;
2262
2263 /**
2264 * Creates new HandleTable with given capacity and load factor.
2265 */
2266 HandleTable(int initialCapacity, float loadFactor) {
2267 this.loadFactor = loadFactor;
2268 spine = new int[initialCapacity];
2269 next = new int[initialCapacity];
2270 objs = new Object[initialCapacity];
2271 threshold = (int) (initialCapacity * loadFactor);
2272 clear();
2273 }
2274
2275 /**
2276 * Assigns next available handle to given object, and returns handle
2277 * value. Handles are assigned in ascending order starting at 0.
2278 */
2279 int assign(Object obj) {
2280 if (size >= next.length) {
2281 growEntries();
2282 }
2283 if (size >= threshold) {
2284 growSpine();
2285 }
2286 insert(obj, size);
2287 return size++;
2288 }
2289
2290 /**
2291 * Looks up and returns handle associated with given object, or -1 if
2292 * no mapping found.
2293 */
2294 int lookup(Object obj) {
2295 if (size == 0) {
2296 return -1;
2297 }
2298 int index = hash(obj) % spine.length;
2299 for (int i = spine[index]; i >= 0; i = next[i]) {
2300 if (objs[i] == obj) {
2301 return i;
2302 }
2303 }
2304 return -1;
2305 }
2306
2307 /**
2308 * Resets table to its initial (empty) state.
2309 */
2310 void clear() {
2311 Arrays.fill(spine, -1);
2312 Arrays.fill(objs, 0, size, null);
2313 size = 0;
2314 }
2315
2316 /**
2317 * Returns the number of mappings currently in table.
2318 */
2319 int size() {
2320 return size;
2321 }
2322
2323 /**
2324 * Inserts mapping object -> handle mapping into table. Assumes table
2325 * is large enough to accommodate new mapping.
2326 */
2327 private void insert(Object obj, int handle) {
2328 int index = hash(obj) % spine.length;
2329 objs[handle] = obj;
2330 next[handle] = spine[index];
2331 spine[index] = handle;
2332 }
2333
2334 /**
2335 * Expands the hash "spine" -- equivalent to increasing the number of
2336 * buckets in a conventional hash table.
2337 */
2338 private void growSpine() {
2339 spine = new int[(spine.length << 1) + 1];
2340 threshold = (int) (spine.length * loadFactor);
2341 Arrays.fill(spine, -1);
2342 for (int i = 0; i < size; i++) {
2343 insert(objs[i], i);
2344 }
2345 }
2346
2347 /**
2348 * Increases hash table capacity by lengthening entry arrays.
2349 */
2350 private void growEntries() {
2351 int newLength = (next.length << 1) + 1;
2352 int[] newNext = new int[newLength];
2353 System.arraycopy(next, 0, newNext, 0, size);
2354 next = newNext;
2355
2356 Object[] newObjs = new Object[newLength];
2357 System.arraycopy(objs, 0, newObjs, 0, size);
2358 objs = newObjs;
2359 }
2360
2361 /**
2362 * Returns hash value for given object.
2363 */
2364 private int hash(Object obj) {
2365 return System.identityHashCode(obj) & 0x7FFFFFFF;
2366 }
2367 }
2368
2369 /**
2370 * Lightweight identity hash table which maps objects to replacement
2371 * objects.
2372 */
2373 private static class ReplaceTable {
2374
2375 /* maps object -> index */
2376 private final HandleTable htab;
2377 /* maps index -> replacement object */
2378 private Object[] reps;
2379
2380 /**
2381 * Creates new ReplaceTable with given capacity and load factor.
2382 */
2383 ReplaceTable(int initialCapacity, float loadFactor) {
2384 htab = new HandleTable(initialCapacity, loadFactor);
2385 reps = new Object[initialCapacity];
2386 }
2387
2388 /**
2389 * Enters mapping from object to replacement object.
2390 */
2391 void assign(Object obj, Object rep) {
2392 int index = htab.assign(obj);
2393 while (index >= reps.length) {
2394 grow();
2395 }
2396 reps[index] = rep;
2397 }
2398
2399 /**
2400 * Looks up and returns replacement for given object. If no
2401 * replacement is found, returns the lookup object itself.
2402 */
2403 Object lookup(Object obj) {
2404 int index = htab.lookup(obj);
2405 return (index >= 0) ? reps[index] : obj;
2406 }
2407
2408 /**
2409 * Resets table to its initial (empty) state.
2410 */
2411 void clear() {
2412 Arrays.fill(reps, 0, htab.size(), null);
2413 htab.clear();
2414 }
2415
2416 /**
2417 * Returns the number of mappings currently in table.
2418 */
2419 int size() {
2420 return htab.size();
2421 }
2422
2423 /**
2424 * Increases table capacity.
2425 */
2426 private void grow() {
2427 Object[] newReps = new Object[(reps.length << 1) + 1];
2428 System.arraycopy(reps, 0, newReps, 0, reps.length);
2429 reps = newReps;
2430 }
2431 }
2432
2433 /**
2434 * Stack to keep debug information about the state of the
2435 * serialization process, for embedding in exception messages.
2436 */
2437 private static class DebugTraceInfoStack {
2438 private final List<String> stack;
2439
2440 DebugTraceInfoStack() {
2441 stack = new ArrayList<>();
2442 }
2443
2444 /**
2445 * Removes all of the elements from enclosed list.
2446 */
2447 void clear() {
2448 stack.clear();
2449 }
2450
2451 /**
2452 * Removes the object at the top of enclosed list.
2453 */
2454 void pop() {
2455 stack.remove(stack.size()-1);
2456 }
2457
2458 /**
2459 * Pushes a String onto the top of enclosed list.
2460 */
2461 void push(String entry) {
2462 stack.add("\t- " + entry);
2463 }
2464
2465 /**
2466 * Returns a string representation of this object
2467 */
2468 public String toString() {
2469 StringJoiner sj = new StringJoiner("\n");
2470 for (int i = stack.size() - 1; i >= 0; i--) {
2471 sj.add(stack.get(i));
2472 }
2473 return sj.toString();
2474 }
2475 }
2476
2477 }