| Methods Summary |
|---|
| protected void | annotateClass(java.lang.Class cl)Subclasses may implement this method to allow class data to be stored in
the stream. By default this method does nothing. The corresponding
method in ObjectInputStream is resolveClass. This method is called
exactly once for each unique class in the stream. The class name and
signature will have already been written to the stream. This method may
make free use of the ObjectOutputStream to save any representation of
the class it deems suitable (for example, the bytes of the class file).
The resolveClass method in the corresponding subclass of
ObjectInputStream must read and use any data or objects written by
annotateClass.
|
| protected void | annotateProxyClass(java.lang.Class cl)Subclasses may implement this method to store custom data in the stream
along with descriptors for dynamic proxy classes.
This method is called exactly once for each unique proxy class
descriptor in the stream. The default implementation of this method in
ObjectOutputStream does nothing.
The corresponding method in ObjectInputStream is
resolveProxyClass. For a given subclass of
ObjectOutputStream that overrides this method, the
resolveProxyClass method in the corresponding subclass of
ObjectInputStream must read any data or objects written by
annotateProxyClass.
|
| private static boolean | auditSubclass(java.lang.Class subcl)Performs reflective checks on given subclass to verify that it doesn't
override security-sensitive non-final methods. Returns true if subclass
is "safe", false otherwise.
Boolean result = (Boolean) AccessController.doPrivileged(
new PrivilegedAction() {
public Object run() {
for (Class cl = subcl;
cl != ObjectOutputStream.class;
cl = cl.getSuperclass())
{
try {
cl.getDeclaredMethod(
"writeUnshared", new Class[] { Object.class });
return Boolean.FALSE;
} catch (NoSuchMethodException ex) {
}
try {
cl.getDeclaredMethod("putFields", (Class[]) null);
return Boolean.FALSE;
} catch (NoSuchMethodException ex) {
}
}
return Boolean.TRUE;
}
}
);
return result.booleanValue();
|
| private void | clear()Clears internal data structures.
subs.clear();
handles.clear();
|
| public void | close()Closes the stream. This method must be called to release any resources
associated with the stream.
flush();
clear();
bout.close();
|
| private void | defaultWriteFields(java.lang.Object obj, java.io.ObjectStreamClass desc)Fetches and writes values of serializable fields of given object to
stream. The given class descriptor specifies which field values to
write, and in which order they should be written.
// REMIND: perform conservative isInstance check here?
desc.checkDefaultSerialize();
int primDataSize = desc.getPrimDataSize();
if (primVals == null || primVals.length < primDataSize) {
primVals = new byte[primDataSize];
}
desc.getPrimFieldValues(obj, primVals);
bout.write(primVals, 0, primDataSize, false);
ObjectStreamField[] fields = desc.getFields(false);
Object[] objVals = new Object[desc.getNumObjFields()];
int numPrimFields = fields.length - objVals.length;
desc.getObjFieldValues(obj, objVals);
for (int i = 0; i < objVals.length; i++) {
if (extendedDebugInfo) {
debugInfoStack.push(
"field (class \"" + desc.getName() + "\", name: \"" +
fields[numPrimFields + i].getName() + "\", type: \"" +
fields[numPrimFields + i].getType() + "\")");
}
try {
writeObject0(objVals[i],
fields[numPrimFields + i].isUnshared());
} finally {
if (extendedDebugInfo) {
debugInfoStack.pop();
}
}
}
|
| public void | defaultWriteObject()Write the non-static and non-transient fields of the current class to
this stream. This may only be called from the writeObject method of the
class being serialized. It will throw the NotActiveException if it is
called otherwise.
if (curObj == null || curDesc == null) {
throw new NotActiveException("not in call to writeObject");
}
bout.setBlockDataMode(false);
defaultWriteFields(curObj, curDesc);
bout.setBlockDataMode(true);
|
| private static native void | doublesToBytes(double[] src, int srcpos, byte[] dst, int dstpos, int ndoubles)Converts specified span of double values into byte values.
|
| protected void | drain()Drain any buffered data in ObjectOutputStream. Similar to flush but
does not propagate the flush to the underlying stream.
bout.drain();
|
| protected boolean | enableReplaceObject(boolean enable)Enable the stream to do replacement of objects in the stream. When
enabled, the replaceObject method is called for every object being
serialized.
If enable is true, and there is a security manager
installed, this method first calls the security manager's
checkPermission method with a
SerializablePermission("enableSubstitution") permission to
ensure it's ok to enable the stream to do replacement of objects in the
stream.
if (enable == enableReplace) {
return enable;
}
if (enable) {
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
sm.checkPermission(SUBSTITUTION_PERMISSION);
}
}
enableReplace = enable;
return !enableReplace;
|
| private static native void | floatsToBytes(float[] src, int srcpos, byte[] dst, int dstpos, int nfloats)Converts specified span of float values into byte values.
|
| public void | flush()Flushes the stream. This will write any buffered output bytes and flush
through to the underlying stream.
bout.flush();
|
| int | getProtocolVersion()Returns protocol version in use.
return protocol;
|
| public java.io.ObjectOutputStream$PutField | putFields()Retrieve the object used to buffer persistent fields to be written to
the stream. The fields will be written to the stream when writeFields
method is called.
if (curPut == null) {
if (curObj == null || curDesc == null) {
throw new NotActiveException("not in call to writeObject");
}
curPut = new PutFieldImpl(curDesc);
}
return curPut;
|
| protected java.lang.Object | replaceObject(java.lang.Object obj)This method will allow trusted subclasses of ObjectOutputStream to
substitute one object for another during serialization. Replacing
objects is disabled until enableReplaceObject is called. The
enableReplaceObject method checks that the stream requesting to do
replacement can be trusted. The first occurrence of each object written
into the serialization stream is passed to replaceObject. Subsequent
references to the object are replaced by the object returned by the
original call to replaceObject. To ensure that the private state of
objects is not unintentionally exposed, only trusted streams may use
replaceObject.
The ObjectOutputStream.writeObject method takes a parameter of type
Object (as opposed to type Serializable) to allow for cases where
non-serializable objects are replaced by serializable ones.
When a subclass is replacing objects it must insure that either a
complementary substitution must be made during deserialization or that
the substituted object is compatible with every field where the
reference will be stored. Objects whose type is not a subclass of the
type of the field or array element abort the serialization by raising an
exception and the object is not be stored.
This method is called only once when each object is first
encountered. All subsequent references to the object will be redirected
to the new object. This method should return the object to be
substituted or the original object.
Null can be returned as the object to be substituted, but may cause
NullReferenceException in classes that contain references to the
original object since they may be expecting an object instead of
null.
return obj;
|
| public void | reset()Reset will disregard the state of any objects already written to the
stream. The state is reset to be the same as a new ObjectOutputStream.
The current point in the stream is marked as reset so the corresponding
ObjectInputStream will be reset at the same point. Objects previously
written to the stream will not be refered to as already being in the
stream. They will be written to the stream again.
if (depth != 0) {
throw new IOException("stream active");
}
bout.setBlockDataMode(false);
bout.writeByte(TC_RESET);
clear();
bout.setBlockDataMode(true);
|
| public void | useProtocolVersion(int version)Specify stream protocol version to use when writing the stream.
This routine provides a hook to enable the current version of
Serialization to write in a format that is backwards compatible to a
previous version of the stream format.
Every effort will be made to avoid introducing additional
backwards incompatibilities; however, sometimes there is no
other alternative.
if (handles.size() != 0) {
// REMIND: implement better check for pristine stream?
throw new IllegalStateException("stream non-empty");
}
switch (version) {
case PROTOCOL_VERSION_1:
case PROTOCOL_VERSION_2:
protocol = version;
break;
default:
throw new IllegalArgumentException(
"unknown version: " + version);
}
|
| private void | verifySubclass()Verifies that this (possibly subclass) instance can be constructed
without violating security constraints: the subclass must not override
security-sensitive non-final methods, or else the
"enableSubclassImplementation" SerializablePermission is checked.
Class cl = getClass();
if (cl == ObjectOutputStream.class) {
return;
}
SecurityManager sm = System.getSecurityManager();
if (sm == null) {
return;
}
processQueue(Caches.subclassAuditsQueue, Caches.subclassAudits);
WeakClassKey key = new WeakClassKey(cl, Caches.subclassAuditsQueue);
Boolean result = Caches.subclassAudits.get(key);
if (result == null) {
result = Boolean.valueOf(auditSubclass(cl));
Caches.subclassAudits.putIfAbsent(key, result);
}
if (result.booleanValue()) {
return;
}
sm.checkPermission(SUBCLASS_IMPLEMENTATION_PERMISSION);
|
| public void | write(int val)Writes a byte. This method will block until the byte is actually
written.
bout.write(val);
|
| public void | write(byte[] buf)Writes an array of bytes. This method will block until the bytes are
actually written.
bout.write(buf, 0, buf.length, false);
|
| public void | write(byte[] buf, int off, int len)Writes a sub array of bytes.
if (buf == null) {
throw new NullPointerException();
}
int endoff = off + len;
if (off < 0 || len < 0 || endoff > buf.length || endoff < 0) {
throw new IndexOutOfBoundsException();
}
bout.write(buf, off, len, false);
|
| private void | writeArray(java.lang.Object array, java.io.ObjectStreamClass desc, boolean unshared)Writes given array object to stream.
bout.writeByte(TC_ARRAY);
writeClassDesc(desc, false);
handles.assign(unshared ? null : array);
Class ccl = desc.forClass().getComponentType();
if (ccl.isPrimitive()) {
if (ccl == Integer.TYPE) {
int[] ia = (int[]) array;
bout.writeInt(ia.length);
bout.writeInts(ia, 0, ia.length);
} else if (ccl == Byte.TYPE) {
byte[] ba = (byte[]) array;
bout.writeInt(ba.length);
bout.write(ba, 0, ba.length, true);
} else if (ccl == Long.TYPE) {
long[] ja = (long[]) array;
bout.writeInt(ja.length);
bout.writeLongs(ja, 0, ja.length);
} else if (ccl == Float.TYPE) {
float[] fa = (float[]) array;
bout.writeInt(fa.length);
bout.writeFloats(fa, 0, fa.length);
} else if (ccl == Double.TYPE) {
double[] da = (double[]) array;
bout.writeInt(da.length);
bout.writeDoubles(da, 0, da.length);
} else if (ccl == Short.TYPE) {
short[] sa = (short[]) array;
bout.writeInt(sa.length);
bout.writeShorts(sa, 0, sa.length);
} else if (ccl == Character.TYPE) {
char[] ca = (char[]) array;
bout.writeInt(ca.length);
bout.writeChars(ca, 0, ca.length);
} else if (ccl == Boolean.TYPE) {
boolean[] za = (boolean[]) array;
bout.writeInt(za.length);
bout.writeBooleans(za, 0, za.length);
} else {
throw new InternalError();
}
} else {
Object[] objs = (Object[]) array;
int len = objs.length;
bout.writeInt(len);
if (extendedDebugInfo) {
debugInfoStack.push(
"array (class \"" + array.getClass().getName() +
"\", size: " + len + ")");
}
try {
for (int i = 0; i < len; i++) {
if (extendedDebugInfo) {
debugInfoStack.push(
"element of array (index: " + i + ")");
}
try {
writeObject0(objs[i], false);
} finally {
if (extendedDebugInfo) {
debugInfoStack.pop();
}
}
}
} finally {
if (extendedDebugInfo) {
debugInfoStack.pop();
}
}
}
|
| public void | writeBoolean(boolean val)Writes a boolean.
bout.writeBoolean(val);
|
| public void | writeByte(int val)Writes an 8 bit byte.
bout.writeByte(val);
|
| public void | writeBytes(java.lang.String str)Writes a String as a sequence of bytes.
bout.writeBytes(str);
|
| public void | writeChar(int val)Writes a 16 bit char.
bout.writeChar(val);
|
| public void | writeChars(java.lang.String str)Writes a String as a sequence of chars.
bout.writeChars(str);
|
| private void | writeClass(java.lang.Class cl, boolean unshared)Writes representation of given class to stream.
bout.writeByte(TC_CLASS);
writeClassDesc(ObjectStreamClass.lookup(cl, true), false);
handles.assign(unshared ? null : cl);
|
| private void | writeClassDesc(java.io.ObjectStreamClass desc, boolean unshared)Writes representation of given class descriptor to stream.
int handle;
if (desc == null) {
writeNull();
} else if (!unshared && (handle = handles.lookup(desc)) != -1) {
writeHandle(handle);
} else if (desc.isProxy()) {
writeProxyDesc(desc, unshared);
} else {
writeNonProxyDesc(desc, unshared);
}
|
| protected void | writeClassDescriptor(java.io.ObjectStreamClass desc)Write the specified class descriptor to the ObjectOutputStream. Class
descriptors are used to identify the classes of objects written to the
stream. Subclasses of ObjectOutputStream may override this method to
customize the way in which class descriptors are written to the
serialization stream. The corresponding method in ObjectInputStream,
readClassDescriptor, should then be overridden to
reconstitute the class descriptor from its custom stream representation.
By default, this method writes class descriptors according to the format
defined in the Object Serialization specification.
Note that this method will only be called if the ObjectOutputStream
is not using the old serialization stream format (set by calling
ObjectOutputStream's useProtocolVersion method). If this
serialization stream is using the old format
(PROTOCOL_VERSION_1), the class descriptor will be written
internally in a manner that cannot be overridden or customized.
desc.writeNonProxy(this);
|
| public void | writeDouble(double val)Writes a 64 bit double.
bout.writeDouble(val);
|
| private void | writeEnum(java.lang.Enum en, java.io.ObjectStreamClass desc, boolean unshared)Writes given enum constant to stream.
bout.writeByte(TC_ENUM);
ObjectStreamClass sdesc = desc.getSuperDesc();
writeClassDesc((sdesc.forClass() == Enum.class) ? desc : sdesc, false);
handles.assign(unshared ? null : en);
writeString(en.name(), false);
|
| private void | writeExternalData(java.io.Externalizable obj)Writes externalizable data of given object by invoking its
writeExternal() method.
Object oldObj = curObj;
ObjectStreamClass oldDesc = curDesc;
PutFieldImpl oldPut = curPut;
curObj = obj;
curDesc = null;
curPut = null;
if (extendedDebugInfo) {
debugInfoStack.push("writeExternal data");
}
try {
if (protocol == PROTOCOL_VERSION_1) {
obj.writeExternal(this);
} else {
bout.setBlockDataMode(true);
obj.writeExternal(this);
bout.setBlockDataMode(false);
bout.writeByte(TC_ENDBLOCKDATA);
}
} finally {
if (extendedDebugInfo) {
debugInfoStack.pop();
}
}
curObj = oldObj;
curDesc = oldDesc;
curPut = oldPut;
|
| private void | writeFatalException(java.io.IOException ex)Attempts to write to stream fatal IOException that has caused
serialization to abort.
/*
* Note: the serialization specification states that if a second
* IOException occurs while attempting to serialize the original fatal
* exception to the stream, then a StreamCorruptedException should be
* thrown (section 2.1). However, due to a bug in previous
* implementations of serialization, StreamCorruptedExceptions were
* rarely (if ever) actually thrown--the "root" exceptions from
* underlying streams were thrown instead. This historical behavior is
* followed here for consistency.
*/
clear();
boolean oldMode = bout.setBlockDataMode(false);
try {
bout.writeByte(TC_EXCEPTION);
writeObject0(ex, false);
clear();
} finally {
bout.setBlockDataMode(oldMode);
}
|
| public void | writeFields()Write the buffered fields to the stream.
if (curPut == null) {
throw new NotActiveException("no current PutField object");
}
bout.setBlockDataMode(false);
curPut.writeFields();
bout.setBlockDataMode(true);
|
| public void | writeFloat(float val)Writes a 32 bit float.
bout.writeFloat(val);
|
| private void | writeHandle(int handle)Writes given object handle to stream.
bout.writeByte(TC_REFERENCE);
bout.writeInt(baseWireHandle + handle);
|
| public void | writeInt(int val)Writes a 32 bit int.
bout.writeInt(val);
|
| public void | writeLong(long val)Writes a 64 bit long.
bout.writeLong(val);
|
| private void | writeNonProxyDesc(java.io.ObjectStreamClass desc, boolean unshared)Writes class descriptor representing a standard (i.e., not a dynamic
proxy) class to stream.
bout.writeByte(TC_CLASSDESC);
handles.assign(unshared ? null : desc);
if (protocol == PROTOCOL_VERSION_1) {
// do not invoke class descriptor write hook with old protocol
desc.writeNonProxy(this);
} else {
writeClassDescriptor(desc);
}
Class cl = desc.forClass();
bout.setBlockDataMode(true);
annotateClass(cl);
bout.setBlockDataMode(false);
bout.writeByte(TC_ENDBLOCKDATA);
writeClassDesc(desc.getSuperDesc(), false);
|
| private void | writeNull()Writes null code to stream.
bout.writeByte(TC_NULL);
|
| public final void | writeObject(java.lang.Object obj)Write the specified object to the ObjectOutputStream. The class of the
object, the signature of the class, and the values of the non-transient
and non-static fields of the class and all of its supertypes are
written. Default serialization for a class can be overridden using the
writeObject and the readObject methods. Objects referenced by this
object are written transitively so that a complete equivalent graph of
objects can be reconstructed by an ObjectInputStream.
Exceptions are thrown for problems with the OutputStream and for
classes that should not be serialized. All exceptions are fatal to the
OutputStream, which is left in an indeterminate state, and it is up to
the caller to ignore or recover the stream state.
if (enableOverride) {
writeObjectOverride(obj);
return;
}
try {
writeObject0(obj, false);
} catch (IOException ex) {
if (depth == 0) {
writeFatalException(ex);
}
throw ex;
}
|
| private void | writeObject0(java.lang.Object obj, boolean unshared)Underlying writeObject/writeUnshared implementation.
boolean oldMode = bout.setBlockDataMode(false);
depth++;
try {
// handle previously written and non-replaceable objects
int h;
if ((obj = subs.lookup(obj)) == null) {
writeNull();
return;
} else if (!unshared && (h = handles.lookup(obj)) != -1) {
writeHandle(h);
return;
} else if (obj instanceof Class) {
writeClass((Class) obj, unshared);
return;
} else if (obj instanceof ObjectStreamClass) {
writeClassDesc((ObjectStreamClass) obj, unshared);
return;
}
// check for replacement object
Object orig = obj;
Class cl = obj.getClass();
ObjectStreamClass desc;
for (;;) {
// REMIND: skip this check for strings/arrays?
Class repCl;
desc = ObjectStreamClass.lookup(cl, true);
if (!desc.hasWriteReplaceMethod() ||
(obj = desc.invokeWriteReplace(obj)) == null ||
(repCl = obj.getClass()) == cl)
{
break;
}
cl = repCl;
}
if (enableReplace) {
Object rep = replaceObject(obj);
if (rep != obj && rep != null) {
cl = rep.getClass();
desc = ObjectStreamClass.lookup(cl, true);
}
obj = rep;
}
// if object replaced, run through original checks a second time
if (obj != orig) {
subs.assign(orig, obj);
if (obj == null) {
writeNull();
return;
} else if (!unshared && (h = handles.lookup(obj)) != -1) {
writeHandle(h);
return;
} else if (obj instanceof Class) {
writeClass((Class) obj, unshared);
return;
} else if (obj instanceof ObjectStreamClass) {
writeClassDesc((ObjectStreamClass) obj, unshared);
return;
}
}
// remaining cases
if (obj instanceof String) {
writeString((String) obj, unshared);
} else if (cl.isArray()) {
writeArray(obj, desc, unshared);
} else if (obj instanceof Enum) {
writeEnum((Enum) obj, desc, unshared);
} else if (obj instanceof Serializable) {
writeOrdinaryObject(obj, desc, unshared);
} else {
if (extendedDebugInfo) {
throw new NotSerializableException(
cl.getName() + "\n" + debugInfoStack.toString());
} else {
throw new NotSerializableException(cl.getName());
}
}
} finally {
depth--;
bout.setBlockDataMode(oldMode);
}
|
| protected void | writeObjectOverride(java.lang.Object obj)Method used by subclasses to override the default writeObject method.
This method is called by trusted subclasses of ObjectInputStream that
constructed ObjectInputStream using the protected no-arg constructor.
The subclass is expected to provide an override method with the modifier
"final".
|
| private void | writeOrdinaryObject(java.lang.Object obj, java.io.ObjectStreamClass desc, boolean unshared)Writes representation of a "ordinary" (i.e., not a String, Class,
ObjectStreamClass, array, or enum constant) serializable object to the
stream.
if (extendedDebugInfo) {
debugInfoStack.push(
(depth == 1 ? "root " : "") + "object (class \"" +
obj.getClass().getName() + "\", " + obj.toString() + ")");
}
try {
desc.checkSerialize();
bout.writeByte(TC_OBJECT);
writeClassDesc(desc, false);
handles.assign(unshared ? null : obj);
if (desc.isExternalizable() && !desc.isProxy()) {
writeExternalData((Externalizable) obj);
} else {
writeSerialData(obj, desc);
}
} finally {
if (extendedDebugInfo) {
debugInfoStack.pop();
}
}
|
| private void | writeProxyDesc(java.io.ObjectStreamClass desc, boolean unshared)Writes class descriptor representing a dynamic proxy class to stream.
bout.writeByte(TC_PROXYCLASSDESC);
handles.assign(unshared ? null : desc);
Class cl = desc.forClass();
Class[] ifaces = cl.getInterfaces();
bout.writeInt(ifaces.length);
for (int i = 0; i < ifaces.length; i++) {
bout.writeUTF(ifaces[i].getName());
}
bout.setBlockDataMode(true);
annotateProxyClass(cl);
bout.setBlockDataMode(false);
bout.writeByte(TC_ENDBLOCKDATA);
writeClassDesc(desc.getSuperDesc(), false);
|
| private void | writeSerialData(java.lang.Object obj, java.io.ObjectStreamClass desc)Writes instance data for each serializable class of given object, from
superclass to subclass.
ObjectStreamClass.ClassDataSlot[] slots = desc.getClassDataLayout();
for (int i = 0; i < slots.length; i++) {
ObjectStreamClass slotDesc = slots[i].desc;
if (slotDesc.hasWriteObjectMethod()) {
Object oldObj = curObj;
ObjectStreamClass oldDesc = curDesc;
PutFieldImpl oldPut = curPut;
curObj = obj;
curDesc = slotDesc;
curPut = null;
if (extendedDebugInfo) {
debugInfoStack.push(
"custom writeObject data (class \"" +
slotDesc.getName() + "\")");
}
try {
bout.setBlockDataMode(true);
slotDesc.invokeWriteObject(obj, this);
bout.setBlockDataMode(false);
bout.writeByte(TC_ENDBLOCKDATA);
} finally {
if (extendedDebugInfo) {
debugInfoStack.pop();
}
}
curObj = oldObj;
curDesc = oldDesc;
curPut = oldPut;
} else {
defaultWriteFields(obj, slotDesc);
}
}
|
| public void | writeShort(int val)Writes a 16 bit short.
bout.writeShort(val);
|
| protected void | writeStreamHeader()The writeStreamHeader method is provided so subclasses can append or
prepend their own header to the stream. It writes the magic number and
version to the stream.
bout.writeShort(STREAM_MAGIC);
bout.writeShort(STREAM_VERSION);
|
| private void | writeString(java.lang.String str, boolean unshared)Writes given string to stream, using standard or long UTF format
depending on string length.
handles.assign(unshared ? null : str);
long utflen = bout.getUTFLength(str);
if (utflen <= 0xFFFF) {
bout.writeByte(TC_STRING);
bout.writeUTF(str, utflen);
} else {
bout.writeByte(TC_LONGSTRING);
bout.writeLongUTF(str, utflen);
}
|
| void | writeTypeString(java.lang.String str)Writes string without allowing it to be replaced in stream. Used by
ObjectStreamClass to write class descriptor type strings.
int handle;
if (str == null) {
writeNull();
} else if ((handle = handles.lookup(str)) != -1) {
writeHandle(handle);
} else {
writeString(str, false);
}
|
| public void | writeUTF(java.lang.String str)Primitive data write of this String in
modified UTF-8
format. Note that there is a
significant difference between writing a String into the stream as
primitive data or as an Object. A String instance written by writeObject
is written into the stream as a String initially. Future writeObject()
calls write references to the string into the stream.
bout.writeUTF(str);
|
| public void | writeUnshared(java.lang.Object obj)Writes an "unshared" object to the ObjectOutputStream. This method is
identical to writeObject, except that it always writes the given object
as a new, unique object in the stream (as opposed to a back-reference
pointing to a previously serialized instance). Specifically:
- An object written via writeUnshared is always serialized in the
same manner as a newly appearing object (an object that has not
been written to the stream yet), regardless of whether or not the
object has been written previously.
- If writeObject is used to write an object that has been previously
written with writeUnshared, the previous writeUnshared operation
is treated as if it were a write of a separate object. In other
words, ObjectOutputStream will never generate back-references to
object data written by calls to writeUnshared.
While writing an object via writeUnshared does not in itself guarantee a
unique reference to the object when it is deserialized, it allows a
single object to be defined multiple times in a stream, so that multiple
calls to readUnshared by the receiver will not conflict. Note that the
rules described above only apply to the base-level object written with
writeUnshared, and not to any transitively referenced sub-objects in the
object graph to be serialized.
ObjectOutputStream subclasses which override this method can only be
constructed in security contexts possessing the
"enableSubclassImplementation" SerializablePermission; any attempt to
instantiate such a subclass without this permission will cause a
SecurityException to be thrown.
try {
writeObject0(obj, true);
} catch (IOException ex) {
if (depth == 0) {
writeFatalException(ex);
}
throw ex;
}
|
