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 abstract static 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 = auditSubclass(cl);
1054 Caches.subclassAudits.putIfAbsent(key, result);
1055 }
1056 if (!result) {
1057 sm.checkPermission(SUBCLASS_IMPLEMENTATION_PERMISSION);
1058 }
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(Class<?> subcl) {
1067 return AccessController.doPrivileged(
1068 new PrivilegedAction<>() {
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 }
1091
1092 /**
1093 * Clears internal data structures.
1094 */
1095 private void clear() {
1096 subs.clear();
1097 handles.clear();
1098 }
1099
1100 /**
1101 * Underlying writeObject/writeUnshared implementation.
1102 */
1103 private void writeObject0(Object obj, boolean unshared)
1104 throws IOException
1105 {
1106 boolean oldMode = bout.setBlockDataMode(false);
1107 depth++;
1108 try {
1109 // handle previously written and non-replaceable objects
1110 int h;
1111 if ((obj = subs.lookup(obj)) == null) {
1112 writeNull();
1113 return;
1114 } else if (!unshared && (h = handles.lookup(obj)) != -1) {
1115 writeHandle(h);
1116 return;
1117 } else if (obj instanceof Class) {
1118 writeClass((Class) obj, unshared);
1119 return;
1120 } else if (obj instanceof ObjectStreamClass) {
1121 writeClassDesc((ObjectStreamClass) obj, unshared);
1122 return;
1123 }
1124
1125 // check for replacement object
1126 Object orig = obj;
1127 Class<?> cl = obj.getClass();
1128 ObjectStreamClass desc;
1129 for (;;) {
1130 // REMIND: skip this check for strings/arrays?
1131 Class<?> repCl;
1132 desc = ObjectStreamClass.lookup(cl, true);
1133 if (!desc.hasWriteReplaceMethod() ||
1134 (obj = desc.invokeWriteReplace(obj)) == null ||
1135 (repCl = obj.getClass()) == cl)
1136 {
1137 break;
1138 }
1139 cl = repCl;
1140 }
1141 if (enableReplace) {
1142 Object rep = replaceObject(obj);
1143 if (rep != obj && rep != null) {
1144 cl = rep.getClass();
1145 desc = ObjectStreamClass.lookup(cl, true);
1146 }
1147 obj = rep;
1148 }
1149
1150 // if object replaced, run through original checks a second time
1151 if (obj != orig) {
1152 subs.assign(orig, obj);
1153 if (obj == null) {
1154 writeNull();
1155 return;
1156 } else if (!unshared && (h = handles.lookup(obj)) != -1) {
1157 writeHandle(h);
1158 return;
1159 } else if (obj instanceof Class) {
1160 writeClass((Class) obj, unshared);
1161 return;
1162 } else if (obj instanceof ObjectStreamClass) {
1163 writeClassDesc((ObjectStreamClass) obj, unshared);
1164 return;
1165 }
1166 }
1167
1168 // remaining cases
1169 if (obj instanceof String) {
1170 writeString((String) obj, unshared);
1171 } else if (cl.isArray()) {
1172 writeArray(obj, desc, unshared);
1173 } else if (obj instanceof Enum) {
1174 writeEnum((Enum<?>) obj, desc, unshared);
1175 } else if (obj instanceof Serializable) {
1176 writeOrdinaryObject(obj, desc, unshared);
1177 } else {
1178 if (extendedDebugInfo) {
1179 throw new NotSerializableException(
1180 cl.getName() + "\n" + debugInfoStack.toString());
1181 } else {
1182 throw new NotSerializableException(cl.getName());
1183 }
1184 }
1185 } finally {
1186 depth--;
1187 bout.setBlockDataMode(oldMode);
1188 }
1189 }
1190
1191 /**
1192 * Writes null code to stream.
1193 */
1194 private void writeNull() throws IOException {
1195 bout.writeByte(TC_NULL);
1196 }
1197
1198 /**
1199 * Writes given object handle to stream.
1200 */
1201 private void writeHandle(int handle) throws IOException {
1202 bout.writeByte(TC_REFERENCE);
1203 bout.writeInt(baseWireHandle + handle);
1204 }
1205
1206 /**
1207 * Writes representation of given class to stream.
1208 */
1209 private void writeClass(Class<?> cl, boolean unshared) throws IOException {
1210 bout.writeByte(TC_CLASS);
1211 writeClassDesc(ObjectStreamClass.lookup(cl, true), false);
1212 handles.assign(unshared ? null : cl);
1213 }
1214
1215 /**
1216 * Writes representation of given class descriptor to stream.
1217 */
1218 private void writeClassDesc(ObjectStreamClass desc, boolean unshared)
1219 throws IOException
1220 {
1221 int handle;
1222 if (desc == null) {
1223 writeNull();
1224 } else if (!unshared && (handle = handles.lookup(desc)) != -1) {
1225 writeHandle(handle);
1226 } else if (desc.isProxy()) {
1227 writeProxyDesc(desc, unshared);
1228 } else {
1229 writeNonProxyDesc(desc, unshared);
1230 }
1231 }
1232
1233 private boolean isCustomSubclass() {
1234 // Return true if this class is a custom subclass of ObjectOutputStream
1235 return getClass().getClassLoader()
1236 != ObjectOutputStream.class.getClassLoader();
1237 }
1238
1239 /**
1240 * Writes class descriptor representing a dynamic proxy class to stream.
1241 */
1242 private void writeProxyDesc(ObjectStreamClass desc, boolean unshared)
1243 throws IOException
1244 {
1245 bout.writeByte(TC_PROXYCLASSDESC);
1246 handles.assign(unshared ? null : desc);
1247
1248 Class<?> cl = desc.forClass();
1249 Class<?>[] ifaces = cl.getInterfaces();
1250 bout.writeInt(ifaces.length);
1251 for (int i = 0; i < ifaces.length; i++) {
1252 bout.writeUTF(ifaces[i].getName());
1253 }
1254
1255 bout.setBlockDataMode(true);
1256 if (cl != null && isCustomSubclass()) {
1257 ReflectUtil.checkPackageAccess(cl);
1258 }
1259 annotateProxyClass(cl);
1260 bout.setBlockDataMode(false);
1261 bout.writeByte(TC_ENDBLOCKDATA);
1262
1263 writeClassDesc(desc.getSuperDesc(), false);
1264 }
1265
1266 /**
1267 * Writes class descriptor representing a standard (i.e., not a dynamic
1268 * proxy) class to stream.
1269 */
1270 private void writeNonProxyDesc(ObjectStreamClass desc, boolean unshared)
1271 throws IOException
1272 {
1273 bout.writeByte(TC_CLASSDESC);
1274 handles.assign(unshared ? null : desc);
1275
1276 if (protocol == PROTOCOL_VERSION_1) {
1277 // do not invoke class descriptor write hook with old protocol
1278 desc.writeNonProxy(this);
1279 } else {
1280 writeClassDescriptor(desc);
1281 }
1282
1283 Class<?> cl = desc.forClass();
1284 bout.setBlockDataMode(true);
1285 if (cl != null && isCustomSubclass()) {
1286 ReflectUtil.checkPackageAccess(cl);
1287 }
1288 annotateClass(cl);
1289 bout.setBlockDataMode(false);
1290 bout.writeByte(TC_ENDBLOCKDATA);
1291
1292 writeClassDesc(desc.getSuperDesc(), false);
1293 }
1294
1295 /**
1296 * Writes given string to stream, using standard or long UTF format
1297 * depending on string length.
1298 */
1299 private void writeString(String str, boolean unshared) throws IOException {
1300 handles.assign(unshared ? null : str);
1301 long utflen = bout.getUTFLength(str);
1302 if (utflen <= 0xFFFF) {
1303 bout.writeByte(TC_STRING);
1304 bout.writeUTF(str, utflen);
1305 } else {
1306 bout.writeByte(TC_LONGSTRING);
1307 bout.writeLongUTF(str, utflen);
1308 }
1309 }
1310
1311 /**
1312 * Writes given array object to stream.
1313 */
1314 private void writeArray(Object array,
1315 ObjectStreamClass desc,
1316 boolean unshared)
1317 throws IOException
1318 {
1319 bout.writeByte(TC_ARRAY);
1320 writeClassDesc(desc, false);
1321 handles.assign(unshared ? null : array);
1322
1323 Class<?> ccl = desc.forClass().getComponentType();
1324 if (ccl.isPrimitive()) {
1325 if (ccl == Integer.TYPE) {
1326 int[] ia = (int[]) array;
1327 bout.writeInt(ia.length);
1328 bout.writeInts(ia, 0, ia.length);
1329 } else if (ccl == Byte.TYPE) {
1330 byte[] ba = (byte[]) array;
1331 bout.writeInt(ba.length);
1332 bout.write(ba, 0, ba.length, true);
1333 } else if (ccl == Long.TYPE) {
1334 long[] ja = (long[]) array;
1335 bout.writeInt(ja.length);
1336 bout.writeLongs(ja, 0, ja.length);
1337 } else if (ccl == Float.TYPE) {
1338 float[] fa = (float[]) array;
1339 bout.writeInt(fa.length);
1340 bout.writeFloats(fa, 0, fa.length);
1341 } else if (ccl == Double.TYPE) {
1342 double[] da = (double[]) array;
1343 bout.writeInt(da.length);
1344 bout.writeDoubles(da, 0, da.length);
1345 } else if (ccl == Short.TYPE) {
1346 short[] sa = (short[]) array;
1347 bout.writeInt(sa.length);
1348 bout.writeShorts(sa, 0, sa.length);
1349 } else if (ccl == Character.TYPE) {
1350 char[] ca = (char[]) array;
1351 bout.writeInt(ca.length);
1352 bout.writeChars(ca, 0, ca.length);
1353 } else if (ccl == Boolean.TYPE) {
1354 boolean[] za = (boolean[]) array;
1355 bout.writeInt(za.length);
1356 bout.writeBooleans(za, 0, za.length);
1357 } else {
1358 throw new InternalError();
1359 }
1360 } else {
1361 Object[] objs = (Object[]) array;
1362 int len = objs.length;
1363 bout.writeInt(len);
1364 if (extendedDebugInfo) {
1365 debugInfoStack.push(
1366 "array (class \"" + array.getClass().getName() +
1367 "\", size: " + len + ")");
1368 }
1369 try {
1370 for (int i = 0; i < len; i++) {
1371 if (extendedDebugInfo) {
1372 debugInfoStack.push(
1373 "element of array (index: " + i + ")");
1374 }
1375 try {
1376 writeObject0(objs[i], false);
1377 } finally {
1378 if (extendedDebugInfo) {
1379 debugInfoStack.pop();
1380 }
1381 }
1382 }
1383 } finally {
1384 if (extendedDebugInfo) {
1385 debugInfoStack.pop();
1386 }
1387 }
1388 }
1389 }
1390
1391 /**
1392 * Writes given enum constant to stream.
1393 */
1394 private void writeEnum(Enum<?> en,
1395 ObjectStreamClass desc,
1396 boolean unshared)
1397 throws IOException
1398 {
1399 bout.writeByte(TC_ENUM);
1400 ObjectStreamClass sdesc = desc.getSuperDesc();
1401 writeClassDesc((sdesc.forClass() == Enum.class) ? desc : sdesc, false);
1402 handles.assign(unshared ? null : en);
1403 writeString(en.name(), false);
1404 }
1405
1406 /**
1407 * Writes representation of a "ordinary" (i.e., not a String, Class,
1408 * ObjectStreamClass, array, or enum constant) serializable object to the
1409 * stream.
1410 */
1411 private void writeOrdinaryObject(Object obj,
1412 ObjectStreamClass desc,
1413 boolean unshared)
1414 throws IOException
1415 {
1416 if (extendedDebugInfo) {
1417 debugInfoStack.push(
1418 (depth == 1 ? "root " : "") + "object (class \"" +
1419 obj.getClass().getName() + "\", " + obj.toString() + ")");
1420 }
1421 try {
1422 desc.checkSerialize();
1423
1424 bout.writeByte(TC_OBJECT);
1425 writeClassDesc(desc, false);
1426 handles.assign(unshared ? null : obj);
1427 if (desc.isExternalizable() && !desc.isProxy()) {
1428 writeExternalData((Externalizable) obj);
1429 } else {
1430 writeSerialData(obj, desc);
1431 }
1432 } finally {
1433 if (extendedDebugInfo) {
1434 debugInfoStack.pop();
1435 }
1436 }
1437 }
1438
1439 /**
1440 * Writes externalizable data of given object by invoking its
1441 * writeExternal() method.
1442 */
1443 private void writeExternalData(Externalizable obj) throws IOException {
1444 PutFieldImpl oldPut = curPut;
1445 curPut = null;
1446
1447 if (extendedDebugInfo) {
1448 debugInfoStack.push("writeExternal data");
1449 }
1450 SerialCallbackContext oldContext = curContext;
1451 try {
1452 curContext = null;
1453 if (protocol == PROTOCOL_VERSION_1) {
1454 obj.writeExternal(this);
1455 } else {
1456 bout.setBlockDataMode(true);
1457 obj.writeExternal(this);
1458 bout.setBlockDataMode(false);
1459 bout.writeByte(TC_ENDBLOCKDATA);
1460 }
1461 } finally {
1462 curContext = oldContext;
1463 if (extendedDebugInfo) {
1464 debugInfoStack.pop();
1465 }
1466 }
1467
1468 curPut = oldPut;
1469 }
1470
1471 /**
1472 * Writes instance data for each serializable class of given object, from
1473 * superclass to subclass.
1474 */
1475 private void writeSerialData(Object obj, ObjectStreamClass desc)
1476 throws IOException
1477 {
1478 ObjectStreamClass.ClassDataSlot[] slots = desc.getClassDataLayout();
1479 for (int i = 0; i < slots.length; i++) {
1480 ObjectStreamClass slotDesc = slots[i].desc;
1481 if (slotDesc.hasWriteObjectMethod()) {
1482 PutFieldImpl oldPut = curPut;
1483 curPut = null;
1484 SerialCallbackContext oldContext = curContext;
1485
1486 if (extendedDebugInfo) {
1487 debugInfoStack.push(
1488 "custom writeObject data (class \"" +
1489 slotDesc.getName() + "\")");
1490 }
1491 try {
1492 curContext = new SerialCallbackContext(obj, slotDesc);
1493 bout.setBlockDataMode(true);
1494 slotDesc.invokeWriteObject(obj, this);
1495 bout.setBlockDataMode(false);
1496 bout.writeByte(TC_ENDBLOCKDATA);
1497 } finally {
1498 curContext.setUsed();
1499 curContext = oldContext;
1500 if (extendedDebugInfo) {
1501 debugInfoStack.pop();
1502 }
1503 }
1504
1505 curPut = oldPut;
1506 } else {
1507 defaultWriteFields(obj, slotDesc);
1508 }
1509 }
1510 }
1511
1512 /**
1513 * Fetches and writes values of serializable fields of given object to
1514 * stream. The given class descriptor specifies which field values to
1515 * write, and in which order they should be written.
1516 */
1517 private void defaultWriteFields(Object obj, ObjectStreamClass desc)
1518 throws IOException
1519 {
1520 Class<?> cl = desc.forClass();
1521 if (cl != null && obj != null && !cl.isInstance(obj)) {
1522 throw new ClassCastException();
1523 }
1524
1525 desc.checkDefaultSerialize();
1526
1527 int primDataSize = desc.getPrimDataSize();
1528 if (primDataSize > 0) {
1529 if (primVals == null || primVals.length < primDataSize) {
1530 primVals = new byte[primDataSize];
1531 }
1532 desc.getPrimFieldValues(obj, primVals);
1533 bout.write(primVals, 0, primDataSize, false);
1534 }
1535
1536 int numObjFields = desc.getNumObjFields();
1537 if (numObjFields > 0) {
1538 ObjectStreamField[] fields = desc.getFields(false);
1539 Object[] objVals = new Object[numObjFields];
1540 int numPrimFields = fields.length - objVals.length;
1541 desc.getObjFieldValues(obj, objVals);
1542 for (int i = 0; i < objVals.length; i++) {
1543 if (extendedDebugInfo) {
1544 debugInfoStack.push(
1545 "field (class \"" + desc.getName() + "\", name: \"" +
1546 fields[numPrimFields + i].getName() + "\", type: \"" +
1547 fields[numPrimFields + i].getType() + "\")");
1548 }
1549 try {
1550 writeObject0(objVals[i],
1551 fields[numPrimFields + i].isUnshared());
1552 } finally {
1553 if (extendedDebugInfo) {
1554 debugInfoStack.pop();
1555 }
1556 }
1557 }
1558 }
1559 }
1560
1561 /**
1562 * Attempts to write to stream fatal IOException that has caused
1563 * serialization to abort.
1564 */
1565 private void writeFatalException(IOException ex) throws IOException {
1566 /*
1567 * Note: the serialization specification states that if a second
1568 * IOException occurs while attempting to serialize the original fatal
1569 * exception to the stream, then a StreamCorruptedException should be
1570 * thrown (section 2.1). However, due to a bug in previous
1571 * implementations of serialization, StreamCorruptedExceptions were
1572 * rarely (if ever) actually thrown--the "root" exceptions from
1573 * underlying streams were thrown instead. This historical behavior is
1574 * followed here for consistency.
1575 */
1576 clear();
1577 boolean oldMode = bout.setBlockDataMode(false);
1578 try {
1579 bout.writeByte(TC_EXCEPTION);
1580 writeObject0(ex, false);
1581 clear();
1582 } finally {
1583 bout.setBlockDataMode(oldMode);
1584 }
1585 }
1586
1587 /**
1588 * Converts specified span of float values into byte values.
1589 */
1590 // REMIND: remove once hotspot inlines Float.floatToIntBits
1591 private static native void floatsToBytes(float[] src, int srcpos,
1592 byte[] dst, int dstpos,
1593 int nfloats);
1594
1595 /**
1596 * Converts specified span of double values into byte values.
1597 */
1598 // REMIND: remove once hotspot inlines Double.doubleToLongBits
1599 private static native void doublesToBytes(double[] src, int srcpos,
1600 byte[] dst, int dstpos,
1601 int ndoubles);
1602
1603 /**
1604 * Default PutField implementation.
1605 */
1606 private class PutFieldImpl extends PutField {
1607
1608 /** class descriptor describing serializable fields */
1609 private final ObjectStreamClass desc;
1610 /** primitive field values */
1611 private final byte[] primVals;
1612 /** object field values */
1613 private final Object[] objVals;
1614
1615 /**
1616 * Creates PutFieldImpl object for writing fields defined in given
1617 * class descriptor.
1618 */
1619 PutFieldImpl(ObjectStreamClass desc) {
1620 this.desc = desc;
1621 primVals = new byte[desc.getPrimDataSize()];
1622 objVals = new Object[desc.getNumObjFields()];
1623 }
1624
1625 public void put(String name, boolean val) {
1626 Bits.putBoolean(primVals, getFieldOffset(name, Boolean.TYPE), val);
1627 }
1628
1629 public void put(String name, byte val) {
1630 primVals[getFieldOffset(name, Byte.TYPE)] = val;
1631 }
1632
1633 public void put(String name, char val) {
1634 Bits.putChar(primVals, getFieldOffset(name, Character.TYPE), val);
1635 }
1636
1637 public void put(String name, short val) {
1638 Bits.putShort(primVals, getFieldOffset(name, Short.TYPE), val);
1639 }
1640
1641 public void put(String name, int val) {
1642 Bits.putInt(primVals, getFieldOffset(name, Integer.TYPE), val);
1643 }
1644
1645 public void put(String name, float val) {
1646 Bits.putFloat(primVals, getFieldOffset(name, Float.TYPE), val);
1647 }
1648
1649 public void put(String name, long val) {
1650 Bits.putLong(primVals, getFieldOffset(name, Long.TYPE), val);
1651 }
1652
1653 public void put(String name, double val) {
1654 Bits.putDouble(primVals, getFieldOffset(name, Double.TYPE), val);
1655 }
1656
1657 public void put(String name, Object val) {
1658 objVals[getFieldOffset(name, Object.class)] = val;
1659 }
1660
1661 // deprecated in ObjectOutputStream.PutField
1662 public void write(ObjectOutput out) throws IOException {
1663 /*
1664 * Applications should *not* use this method to write PutField
1665 * data, as it will lead to stream corruption if the PutField
1666 * object writes any primitive data (since block data mode is not
1667 * unset/set properly, as is done in OOS.writeFields()). This
1668 * broken implementation is being retained solely for behavioral
1669 * compatibility, in order to support applications which use
1670 * OOS.PutField.write() for writing only non-primitive data.
1671 *
1672 * Serialization of unshared objects is not implemented here since
1673 * it is not necessary for backwards compatibility; also, unshared
1674 * semantics may not be supported by the given ObjectOutput
1675 * instance. Applications which write unshared objects using the
1676 * PutField API must use OOS.writeFields().
1677 */
1678 if (ObjectOutputStream.this != out) {
1679 throw new IllegalArgumentException("wrong stream");
1680 }
1681 out.write(primVals, 0, primVals.length);
1682
1683 ObjectStreamField[] fields = desc.getFields(false);
1684 int numPrimFields = fields.length - objVals.length;
1685 // REMIND: warn if numPrimFields > 0?
1686 for (int i = 0; i < objVals.length; i++) {
1687 if (fields[numPrimFields + i].isUnshared()) {
1688 throw new IOException("cannot write unshared object");
1689 }
1690 out.writeObject(objVals[i]);
1691 }
1692 }
1693
1694 /**
1695 * Writes buffered primitive data and object fields to stream.
1696 */
1697 void writeFields() throws IOException {
1698 bout.write(primVals, 0, primVals.length, false);
1699
1700 ObjectStreamField[] fields = desc.getFields(false);
1701 int numPrimFields = fields.length - objVals.length;
1702 for (int i = 0; i < objVals.length; i++) {
1703 if (extendedDebugInfo) {
1704 debugInfoStack.push(
1705 "field (class \"" + desc.getName() + "\", name: \"" +
1706 fields[numPrimFields + i].getName() + "\", type: \"" +
1707 fields[numPrimFields + i].getType() + "\")");
1708 }
1709 try {
1710 writeObject0(objVals[i],
1711 fields[numPrimFields + i].isUnshared());
1712 } finally {
1713 if (extendedDebugInfo) {
1714 debugInfoStack.pop();
1715 }
1716 }
1717 }
1718 }
1719
1720 /**
1721 * Returns offset of field with given name and type. A specified type
1722 * of null matches all types, Object.class matches all non-primitive
1723 * types, and any other non-null type matches assignable types only.
1724 * Throws IllegalArgumentException if no matching field found.
1725 */
1726 private int getFieldOffset(String name, Class<?> type) {
1727 ObjectStreamField field = desc.getField(name, type);
1728 if (field == null) {
1729 throw new IllegalArgumentException("no such field " + name +
1730 " with type " + type);
1731 }
1732 return field.getOffset();
1733 }
1734 }
1735
1736 /**
1737 * Buffered output stream with two modes: in default mode, outputs data in
1738 * same format as DataOutputStream; in "block data" mode, outputs data
1739 * bracketed by block data markers (see object serialization specification
1740 * for details).
1741 */
1742 private static class BlockDataOutputStream
1743 extends OutputStream implements DataOutput
1744 {
1745 /** maximum data block length */
1746 private static final int MAX_BLOCK_SIZE = 1024;
1747 /** maximum data block header length */
1748 private static final int MAX_HEADER_SIZE = 5;
1749 /** (tunable) length of char buffer (for writing strings) */
1750 private static final int CHAR_BUF_SIZE = 256;
1751
1752 /** buffer for writing general/block data */
1753 private final byte[] buf = new byte[MAX_BLOCK_SIZE];
1754 /** buffer for writing block data headers */
1755 private final byte[] hbuf = new byte[MAX_HEADER_SIZE];
1756 /** char buffer for fast string writes */
1757 private final char[] cbuf = new char[CHAR_BUF_SIZE];
1758
1759 /** block data mode */
1760 private boolean blkmode = false;
1761 /** current offset into buf */
1762 private int pos = 0;
1763
1764 /** underlying output stream */
1765 private final OutputStream out;
1766 /** loopback stream (for data writes that span data blocks) */
1767 private final DataOutputStream dout;
1768
1769 /**
1770 * Creates new BlockDataOutputStream on top of given underlying stream.
1771 * Block data mode is turned off by default.
1772 */
1773 BlockDataOutputStream(OutputStream out) {
1774 this.out = out;
1775 dout = new DataOutputStream(this);
1776 }
1777
1778 /**
1779 * Sets block data mode to the given mode (true == on, false == off)
1780 * and returns the previous mode value. If the new mode is the same as
1781 * the old mode, no action is taken. If the new mode differs from the
1782 * old mode, any buffered data is flushed before switching to the new
1783 * mode.
1784 */
1785 boolean setBlockDataMode(boolean mode) throws IOException {
1786 if (blkmode == mode) {
1787 return blkmode;
1788 }
1789 drain();
1790 blkmode = mode;
1791 return !blkmode;
1792 }
1793
1794 /**
1795 * Returns true if the stream is currently in block data mode, false
1796 * otherwise.
1797 */
1798 boolean getBlockDataMode() {
1799 return blkmode;
1800 }
1801
1802 /* ----------------- generic output stream methods ----------------- */
1803 /*
1804 * The following methods are equivalent to their counterparts in
1805 * OutputStream, except that they partition written data into data
1806 * blocks when in block data mode.
1807 */
1808
1809 public void write(int b) throws IOException {
1810 if (pos >= MAX_BLOCK_SIZE) {
1811 drain();
1812 }
1813 buf[pos++] = (byte) b;
1814 }
1815
1816 public void write(byte[] b) throws IOException {
1817 write(b, 0, b.length, false);
1818 }
1819
1820 public void write(byte[] b, int off, int len) throws IOException {
1821 write(b, off, len, false);
1822 }
1823
1824 public void flush() throws IOException {
1825 drain();
1826 out.flush();
1827 }
1828
1829 public void close() throws IOException {
1830 flush();
1831 out.close();
1832 }
1833
1834 /**
1835 * Writes specified span of byte values from given array. If copy is
1836 * true, copies the values to an intermediate buffer before writing
1837 * them to underlying stream (to avoid exposing a reference to the
1838 * original byte array).
1839 */
1840 void write(byte[] b, int off, int len, boolean copy)
1841 throws IOException
1842 {
1843 if (!(copy || blkmode)) { // write directly
1844 drain();
1845 out.write(b, off, len);
1846 return;
1847 }
1848
1849 while (len > 0) {
1850 if (pos >= MAX_BLOCK_SIZE) {
1851 drain();
1852 }
1853 if (len >= MAX_BLOCK_SIZE && !copy && pos == 0) {
1854 // avoid unnecessary copy
1855 writeBlockHeader(MAX_BLOCK_SIZE);
1856 out.write(b, off, MAX_BLOCK_SIZE);
1857 off += MAX_BLOCK_SIZE;
1858 len -= MAX_BLOCK_SIZE;
1859 } else {
1860 int wlen = Math.min(len, MAX_BLOCK_SIZE - pos);
1861 System.arraycopy(b, off, buf, pos, wlen);
1862 pos += wlen;
1863 off += wlen;
1864 len -= wlen;
1865 }
1866 }
1867 }
1868
1869 /**
1870 * Writes all buffered data from this stream to the underlying stream,
1871 * but does not flush underlying stream.
1872 */
1873 void drain() throws IOException {
1874 if (pos == 0) {
1875 return;
1876 }
1877 if (blkmode) {
1878 writeBlockHeader(pos);
1879 }
1880 out.write(buf, 0, pos);
1881 pos = 0;
1882 }
1883
1884 /**
1885 * Writes block data header. Data blocks shorter than 256 bytes are
1886 * prefixed with a 2-byte header; all others start with a 5-byte
1887 * header.
1888 */
1889 private void writeBlockHeader(int len) throws IOException {
1890 if (len <= 0xFF) {
1891 hbuf[0] = TC_BLOCKDATA;
1892 hbuf[1] = (byte) len;
1893 out.write(hbuf, 0, 2);
1894 } else {
1895 hbuf[0] = TC_BLOCKDATALONG;
1896 Bits.putInt(hbuf, 1, len);
1897 out.write(hbuf, 0, 5);
1898 }
1899 }
1900
1901
1902 /* ----------------- primitive data output methods ----------------- */
1903 /*
1904 * The following methods are equivalent to their counterparts in
1905 * DataOutputStream, except that they partition written data into data
1906 * blocks when in block data mode.
1907 */
1908
1909 public void writeBoolean(boolean v) throws IOException {
1910 if (pos >= MAX_BLOCK_SIZE) {
1911 drain();
1912 }
1913 Bits.putBoolean(buf, pos++, v);
1914 }
1915
1916 public void writeByte(int v) throws IOException {
1917 if (pos >= MAX_BLOCK_SIZE) {
1918 drain();
1919 }
1920 buf[pos++] = (byte) v;
1921 }
1922
1923 public void writeChar(int v) throws IOException {
1924 if (pos + 2 <= MAX_BLOCK_SIZE) {
1925 Bits.putChar(buf, pos, (char) v);
1926 pos += 2;
1927 } else {
1928 dout.writeChar(v);
1929 }
1930 }
1931
1932 public void writeShort(int v) throws IOException {
1933 if (pos + 2 <= MAX_BLOCK_SIZE) {
1934 Bits.putShort(buf, pos, (short) v);
1935 pos += 2;
1936 } else {
1937 dout.writeShort(v);
1938 }
1939 }
1940
1941 public void writeInt(int v) throws IOException {
1942 if (pos + 4 <= MAX_BLOCK_SIZE) {
1943 Bits.putInt(buf, pos, v);
1944 pos += 4;
1945 } else {
1946 dout.writeInt(v);
1947 }
1948 }
1949
1950 public void writeFloat(float v) throws IOException {
1951 if (pos + 4 <= MAX_BLOCK_SIZE) {
1952 Bits.putFloat(buf, pos, v);
1953 pos += 4;
1954 } else {
1955 dout.writeFloat(v);
1956 }
1957 }
1958
1959 public void writeLong(long v) throws IOException {
1960 if (pos + 8 <= MAX_BLOCK_SIZE) {
1961 Bits.putLong(buf, pos, v);
1962 pos += 8;
1963 } else {
1964 dout.writeLong(v);
1965 }
1966 }
1967
1968 public void writeDouble(double v) throws IOException {
1969 if (pos + 8 <= MAX_BLOCK_SIZE) {
1970 Bits.putDouble(buf, pos, v);
1971 pos += 8;
1972 } else {
1973 dout.writeDouble(v);
1974 }
1975 }
1976
1977 public void writeBytes(String s) throws IOException {
1978 int endoff = s.length();
1979 int cpos = 0;
1980 int csize = 0;
1981 for (int off = 0; off < endoff; ) {
1982 if (cpos >= csize) {
1983 cpos = 0;
1984 csize = Math.min(endoff - off, CHAR_BUF_SIZE);
1985 s.getChars(off, off + csize, cbuf, 0);
1986 }
1987 if (pos >= MAX_BLOCK_SIZE) {
1988 drain();
1989 }
1990 int n = Math.min(csize - cpos, MAX_BLOCK_SIZE - pos);
1991 int stop = pos + n;
1992 while (pos < stop) {
1993 buf[pos++] = (byte) cbuf[cpos++];
1994 }
1995 off += n;
1996 }
1997 }
1998
1999 public void writeChars(String s) throws IOException {
2000 int endoff = s.length();
2001 for (int off = 0; off < endoff; ) {
2002 int csize = Math.min(endoff - off, CHAR_BUF_SIZE);
2003 s.getChars(off, off + csize, cbuf, 0);
2004 writeChars(cbuf, 0, csize);
2005 off += csize;
2006 }
2007 }
2008
2009 public void writeUTF(String s) throws IOException {
2010 writeUTF(s, getUTFLength(s));
2011 }
2012
2013
2014 /* -------------- primitive data array output methods -------------- */
2015 /*
2016 * The following methods write out spans of primitive data values.
2017 * Though equivalent to calling the corresponding primitive write
2018 * methods repeatedly, these methods are optimized for writing groups
2019 * of primitive data values more efficiently.
2020 */
2021
2022 void writeBooleans(boolean[] v, int off, int len) throws IOException {
2023 int endoff = off + len;
2024 while (off < endoff) {
2025 if (pos >= MAX_BLOCK_SIZE) {
2026 drain();
2027 }
2028 int stop = Math.min(endoff, off + (MAX_BLOCK_SIZE - pos));
2029 while (off < stop) {
2030 Bits.putBoolean(buf, pos++, v[off++]);
2031 }
2032 }
2033 }
2034
2035 void writeChars(char[] v, int off, int len) throws IOException {
2036 int limit = MAX_BLOCK_SIZE - 2;
2037 int endoff = off + len;
2038 while (off < endoff) {
2039 if (pos <= limit) {
2040 int avail = (MAX_BLOCK_SIZE - pos) >> 1;
2041 int stop = Math.min(endoff, off + avail);
2042 while (off < stop) {
2043 Bits.putChar(buf, pos, v[off++]);
2044 pos += 2;
2045 }
2046 } else {
2047 dout.writeChar(v[off++]);
2048 }
2049 }
2050 }
2051
2052 void writeShorts(short[] v, int off, int len) throws IOException {
2053 int limit = MAX_BLOCK_SIZE - 2;
2054 int endoff = off + len;
2055 while (off < endoff) {
2056 if (pos <= limit) {
2057 int avail = (MAX_BLOCK_SIZE - pos) >> 1;
2058 int stop = Math.min(endoff, off + avail);
2059 while (off < stop) {
2060 Bits.putShort(buf, pos, v[off++]);
2061 pos += 2;
2062 }
2063 } else {
2064 dout.writeShort(v[off++]);
2065 }
2066 }
2067 }
2068
2069 void writeInts(int[] v, int off, int len) throws IOException {
2070 int limit = MAX_BLOCK_SIZE - 4;
2071 int endoff = off + len;
2072 while (off < endoff) {
2073 if (pos <= limit) {
2074 int avail = (MAX_BLOCK_SIZE - pos) >> 2;
2075 int stop = Math.min(endoff, off + avail);
2076 while (off < stop) {
2077 Bits.putInt(buf, pos, v[off++]);
2078 pos += 4;
2079 }
2080 } else {
2081 dout.writeInt(v[off++]);
2082 }
2083 }
2084 }
2085
2086 void writeFloats(float[] v, int off, int len) throws IOException {
2087 int limit = MAX_BLOCK_SIZE - 4;
2088 int endoff = off + len;
2089 while (off < endoff) {
2090 if (pos <= limit) {
2091 int avail = (MAX_BLOCK_SIZE - pos) >> 2;
2092 int chunklen = Math.min(endoff - off, avail);
2093 floatsToBytes(v, off, buf, pos, chunklen);
2094 off += chunklen;
2095 pos += chunklen << 2;
2096 } else {
2097 dout.writeFloat(v[off++]);
2098 }
2099 }
2100 }
2101
2102 void writeLongs(long[] v, int off, int len) throws IOException {
2103 int limit = MAX_BLOCK_SIZE - 8;
2104 int endoff = off + len;
2105 while (off < endoff) {
2106 if (pos <= limit) {
2107 int avail = (MAX_BLOCK_SIZE - pos) >> 3;
2108 int stop = Math.min(endoff, off + avail);
2109 while (off < stop) {
2110 Bits.putLong(buf, pos, v[off++]);
2111 pos += 8;
2112 }
2113 } else {
2114 dout.writeLong(v[off++]);
2115 }
2116 }
2117 }
2118
2119 void writeDoubles(double[] v, int off, int len) throws IOException {
2120 int limit = MAX_BLOCK_SIZE - 8;
2121 int endoff = off + len;
2122 while (off < endoff) {
2123 if (pos <= limit) {
2124 int avail = (MAX_BLOCK_SIZE - pos) >> 3;
2125 int chunklen = Math.min(endoff - off, avail);
2126 doublesToBytes(v, off, buf, pos, chunklen);
2127 off += chunklen;
2128 pos += chunklen << 3;
2129 } else {
2130 dout.writeDouble(v[off++]);
2131 }
2132 }
2133 }
2134
2135 /**
2136 * Returns the length in bytes of the UTF encoding of the given string.
2137 */
2138 long getUTFLength(String s) {
2139 int len = s.length();
2140 long utflen = 0;
2141 for (int off = 0; off < len; ) {
2142 int csize = Math.min(len - off, CHAR_BUF_SIZE);
2143 s.getChars(off, off + csize, cbuf, 0);
2144 for (int cpos = 0; cpos < csize; cpos++) {
2145 char c = cbuf[cpos];
2146 if (c >= 0x0001 && c <= 0x007F) {
2147 utflen++;
2148 } else if (c > 0x07FF) {
2149 utflen += 3;
2150 } else {
2151 utflen += 2;
2152 }
2153 }
2154 off += csize;
2155 }
2156 return utflen;
2157 }
2158
2159 /**
2160 * Writes the given string in UTF format. This method is used in
2161 * situations where the UTF encoding length of the string is already
2162 * known; specifying it explicitly avoids a prescan of the string to
2163 * determine its UTF length.
2164 */
2165 void writeUTF(String s, long utflen) throws IOException {
2166 if (utflen > 0xFFFFL) {
2167 throw new UTFDataFormatException();
2168 }
2169 writeShort((int) utflen);
2170 if (utflen == (long) s.length()) {
2171 writeBytes(s);
2172 } else {
2173 writeUTFBody(s);
2174 }
2175 }
2176
2177 /**
2178 * Writes given string in "long" UTF format. "Long" UTF format is
2179 * identical to standard UTF, except that it uses an 8 byte header
2180 * (instead of the standard 2 bytes) to convey the UTF encoding length.
2181 */
2182 void writeLongUTF(String s) throws IOException {
2183 writeLongUTF(s, getUTFLength(s));
2184 }
2185
2186 /**
2187 * Writes given string in "long" UTF format, where the UTF encoding
2188 * length of the string is already known.
2189 */
2190 void writeLongUTF(String s, long utflen) throws IOException {
2191 writeLong(utflen);
2192 if (utflen == (long) s.length()) {
2193 writeBytes(s);
2194 } else {
2195 writeUTFBody(s);
2196 }
2197 }
2198
2199 /**
2200 * Writes the "body" (i.e., the UTF representation minus the 2-byte or
2201 * 8-byte length header) of the UTF encoding for the given string.
2202 */
2203 private void writeUTFBody(String s) throws IOException {
2204 int limit = MAX_BLOCK_SIZE - 3;
2205 int len = s.length();
2206 for (int off = 0; off < len; ) {
2207 int csize = Math.min(len - off, CHAR_BUF_SIZE);
2208 s.getChars(off, off + csize, cbuf, 0);
2209 for (int cpos = 0; cpos < csize; cpos++) {
2210 char c = cbuf[cpos];
2211 if (pos <= limit) {
2212 if (c <= 0x007F && c != 0) {
2213 buf[pos++] = (byte) c;
2214 } else if (c > 0x07FF) {
2215 buf[pos + 2] = (byte) (0x80 | ((c >> 0) & 0x3F));
2216 buf[pos + 1] = (byte) (0x80 | ((c >> 6) & 0x3F));
2217 buf[pos + 0] = (byte) (0xE0 | ((c >> 12) & 0x0F));
2218 pos += 3;
2219 } else {
2220 buf[pos + 1] = (byte) (0x80 | ((c >> 0) & 0x3F));
2221 buf[pos + 0] = (byte) (0xC0 | ((c >> 6) & 0x1F));
2222 pos += 2;
2223 }
2224 } else { // write one byte at a time to normalize block
2225 if (c <= 0x007F && c != 0) {
2226 write(c);
2227 } else if (c > 0x07FF) {
2228 write(0xE0 | ((c >> 12) & 0x0F));
2229 write(0x80 | ((c >> 6) & 0x3F));
2230 write(0x80 | ((c >> 0) & 0x3F));
2231 } else {
2232 write(0xC0 | ((c >> 6) & 0x1F));
2233 write(0x80 | ((c >> 0) & 0x3F));
2234 }
2235 }
2236 }
2237 off += csize;
2238 }
2239 }
2240 }
2241
2242 /**
2243 * Lightweight identity hash table which maps objects to integer handles,
2244 * assigned in ascending order.
2245 */
2246 private static class HandleTable {
2247
2248 /* number of mappings in table/next available handle */
2249 private int size;
2250 /* size threshold determining when to expand hash spine */
2251 private int threshold;
2252 /* factor for computing size threshold */
2253 private final float loadFactor;
2254 /* maps hash value -> candidate handle value */
2255 private int[] spine;
2256 /* maps handle value -> next candidate handle value */
2257 private int[] next;
2258 /* maps handle value -> associated object */
2259 private Object[] objs;
2260
2261 /**
2262 * Creates new HandleTable with given capacity and load factor.
2263 */
2264 HandleTable(int initialCapacity, float loadFactor) {
2265 this.loadFactor = loadFactor;
2266 spine = new int[initialCapacity];
2267 next = new int[initialCapacity];
2268 objs = new Object[initialCapacity];
2269 threshold = (int) (initialCapacity * loadFactor);
2270 clear();
2271 }
2272
2273 /**
2274 * Assigns next available handle to given object, and returns handle
2275 * value. Handles are assigned in ascending order starting at 0.
2276 */
2277 int assign(Object obj) {
2278 if (size >= next.length) {
2279 growEntries();
2280 }
2281 if (size >= threshold) {
2282 growSpine();
2283 }
2284 insert(obj, size);
2285 return size++;
2286 }
2287
2288 /**
2289 * Looks up and returns handle associated with given object, or -1 if
2290 * no mapping found.
2291 */
2292 int lookup(Object obj) {
2293 if (size == 0) {
2294 return -1;
2295 }
2296 int index = hash(obj) % spine.length;
2297 for (int i = spine[index]; i >= 0; i = next[i]) {
2298 if (objs[i] == obj) {
2299 return i;
2300 }
2301 }
2302 return -1;
2303 }
2304
2305 /**
2306 * Resets table to its initial (empty) state.
2307 */
2308 void clear() {
2309 Arrays.fill(spine, -1);
2310 Arrays.fill(objs, 0, size, null);
2311 size = 0;
2312 }
2313
2314 /**
2315 * Returns the number of mappings currently in table.
2316 */
2317 int size() {
2318 return size;
2319 }
2320
2321 /**
2322 * Inserts mapping object -> handle mapping into table. Assumes table
2323 * is large enough to accommodate new mapping.
2324 */
2325 private void insert(Object obj, int handle) {
2326 int index = hash(obj) % spine.length;
2327 objs[handle] = obj;
2328 next[handle] = spine[index];
2329 spine[index] = handle;
2330 }
2331
2332 /**
2333 * Expands the hash "spine" -- equivalent to increasing the number of
2334 * buckets in a conventional hash table.
2335 */
2336 private void growSpine() {
2337 spine = new int[(spine.length << 1) + 1];
2338 threshold = (int) (spine.length * loadFactor);
2339 Arrays.fill(spine, -1);
2340 for (int i = 0; i < size; i++) {
2341 insert(objs[i], i);
2342 }
2343 }
2344
2345 /**
2346 * Increases hash table capacity by lengthening entry arrays.
2347 */
2348 private void growEntries() {
2349 int newLength = (next.length << 1) + 1;
2350 int[] newNext = new int[newLength];
2351 System.arraycopy(next, 0, newNext, 0, size);
2352 next = newNext;
2353
2354 Object[] newObjs = new Object[newLength];
2355 System.arraycopy(objs, 0, newObjs, 0, size);
2356 objs = newObjs;
2357 }
2358
2359 /**
2360 * Returns hash value for given object.
2361 */
2362 private int hash(Object obj) {
2363 return System.identityHashCode(obj) & 0x7FFFFFFF;
2364 }
2365 }
2366
2367 /**
2368 * Lightweight identity hash table which maps objects to replacement
2369 * objects.
2370 */
2371 private static class ReplaceTable {
2372
2373 /* maps object -> index */
2374 private final HandleTable htab;
2375 /* maps index -> replacement object */
2376 private Object[] reps;
2377
2378 /**
2379 * Creates new ReplaceTable with given capacity and load factor.
2380 */
2381 ReplaceTable(int initialCapacity, float loadFactor) {
2382 htab = new HandleTable(initialCapacity, loadFactor);
2383 reps = new Object[initialCapacity];
2384 }
2385
2386 /**
2387 * Enters mapping from object to replacement object.
2388 */
2389 void assign(Object obj, Object rep) {
2390 int index = htab.assign(obj);
2391 while (index >= reps.length) {
2392 grow();
2393 }
2394 reps[index] = rep;
2395 }
2396
2397 /**
2398 * Looks up and returns replacement for given object. If no
2399 * replacement is found, returns the lookup object itself.
2400 */
2401 Object lookup(Object obj) {
2402 int index = htab.lookup(obj);
2403 return (index >= 0) ? reps[index] : obj;
2404 }
2405
2406 /**
2407 * Resets table to its initial (empty) state.
2408 */
2409 void clear() {
2410 Arrays.fill(reps, 0, htab.size(), null);
2411 htab.clear();
2412 }
2413
2414 /**
2415 * Returns the number of mappings currently in table.
2416 */
2417 int size() {
2418 return htab.size();
2419 }
2420
2421 /**
2422 * Increases table capacity.
2423 */
2424 private void grow() {
2425 Object[] newReps = new Object[(reps.length << 1) + 1];
2426 System.arraycopy(reps, 0, newReps, 0, reps.length);
2427 reps = newReps;
2428 }
2429 }
2430
2431 /**
2432 * Stack to keep debug information about the state of the
2433 * serialization process, for embedding in exception messages.
2434 */
2435 private static class DebugTraceInfoStack {
2436 private final List<String> stack;
2437
2438 DebugTraceInfoStack() {
2439 stack = new ArrayList<>();
2440 }
2441
2442 /**
2443 * Removes all of the elements from enclosed list.
2444 */
2445 void clear() {
2446 stack.clear();
2447 }
2448
2449 /**
2450 * Removes the object at the top of enclosed list.
2451 */
2452 void pop() {
2453 stack.remove(stack.size()-1);
2454 }
2455
2456 /**
2457 * Pushes a String onto the top of enclosed list.
2458 */
2459 void push(String entry) {
2460 stack.add("\t- " + entry);
2461 }
2462
2463 /**
2464 * Returns a string representation of this object
2465 */
2466 public String toString() {
2467 StringJoiner sj = new StringJoiner("\n");
2468 for (int i = stack.size() - 1; i >= 0; i--) {
2469 sj.add(stack.get(i));
2470 }
2471 return sj.toString();
2472 }
2473 }
2474
2475 }