org.jboss.marshalling
Class MarshallerObjectOutputStream

java.lang.Object
  java.io.OutputStream
      java.io.ObjectOutputStream
          org.jboss.marshalling.MarshallerObjectOutputStream

All Implemented Interfaces:

Closeable, DataOutput, Flushable, ObjectOutput, ObjectStreamConstants

public abstract class MarshallerObjectOutputStream
extends ObjectOutputStream

A marshaller's object output stream. Used by marshallers for compatibility with Java serialization. Instances of this class may be passed in to the overriden serialization methods for a class implementing Serializable.

This class is not part of the marshalling API; rather it is intended for marshaller implementors to make it easier to develop Java serialization-compatible marshallers.

Nested Class Summary

Nested classes/interfaces inherited from class java.io.ObjectOutputStream

ObjectOutputStream.PutField

Field Summary

Fields inherited from interface java.io.ObjectStreamConstants

baseWireHandle, PROTOCOL_VERSION_1, PROTOCOL_VERSION_2, SC_BLOCK_DATA, SC_ENUM, SC_EXTERNALIZABLE, SC_SERIALIZABLE, SC_WRITE_METHOD, STREAM_MAGIC, STREAM_VERSION, SUBCLASS_IMPLEMENTATION_PERMISSION, SUBSTITUTION_PERMISSION, TC_ARRAY, TC_BASE, TC_BLOCKDATA, TC_BLOCKDATALONG, TC_CLASS, TC_CLASSDESC, TC_ENDBLOCKDATA, TC_ENUM, TC_EXCEPTION, TC_LONGSTRING, TC_MAX, TC_NULL, TC_OBJECT, TC_PROXYCLASSDESC, TC_REFERENCE, TC_RESET, TC_STRING

Constructor Summary

protected

MarshallerObjectOutputStream(Marshaller output) Construct a new instance that delegates to the given marshaller.

Method Summary

protected void	annotateClass(Class<?> cl) Subclasses may implement this method to allow class data to be stored in the stream.
protected void	annotateProxyClass(Class<?> cl) Subclasses may implement this method to store custom data in the stream along with descriptors for dynamic proxy classes.
void	close() Closes the stream.
abstract void	defaultWriteObject() Write the non-static and non-transient fields of the current class to this stream.
protected void	drain() Drain any buffered data in ObjectOutputStream.
protected boolean	enableReplaceObject(boolean enable) Enable the stream to do replacement of objects in the stream.
void	flush() Flushes the stream.
abstract ObjectOutputStream.PutField	putFields() Retrieve the object used to buffer persistent fields to be written to the stream.
protected Object	replaceObject(Object obj) This method will allow trusted subclasses of ObjectOutputStream to substitute one object for another during serialization.
void	reset() Reset will disregard the state of any objects already written to the stream.
void	useProtocolVersion(int version) Specify stream protocol version to use when writing the stream.
void	write(byte[] buf) Writes an array of bytes.
void	write(byte[] buf, int off, int len) Writes a sub array of bytes.
void	write(int val) Writes a byte.
void	writeBoolean(boolean val) Writes a boolean.
void	writeByte(int val) Writes an 8 bit byte.
void	writeBytes(String str) Writes a String as a sequence of bytes.
void	writeChar(int val) Writes a 16 bit char.
void	writeChars(String str) Writes a String as a sequence of chars.
protected void	writeClassDescriptor(ObjectStreamClass desc) Write the specified class descriptor to the ObjectOutputStream.
void	writeDouble(double val) Writes a 64 bit double.
abstract void	writeFields() Write the buffered fields to the stream.
void	writeFloat(float val) Writes a 32 bit float.
void	writeInt(int val) Writes a 32 bit int.
void	writeLong(long val) Writes a 64 bit long.
protected void	writeObjectOverride(Object obj) Method used by subclasses to override the default writeObject method.
void	writeShort(int val) Writes a 16 bit short.
protected void	writeStreamHeader() The writeStreamHeader method is provided so subclasses can append or prepend their own header to the stream.
void	writeUnshared(Object obj) Writes an "unshared" object to the ObjectOutputStream.
void	writeUTF(String str) Primitive data write of this String in modified UTF-8 format.

Methods inherited from class java.io.ObjectOutputStream

writeObject

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MarshallerObjectOutputStream

protected MarshallerObjectOutputStream(Marshaller output)
                                throws IOException,
                                       SecurityException

Construct a new instance that delegates to the given marshaller.

Parameters:

output - the delegate marshaller

Throws:

IOException - if an I/O error occurs

SecurityException - if the caller does not have permission to construct an instance of this class

Method Detail

writeObjectOverride

protected void writeObjectOverride(Object obj)
                            throws IOException

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".

Overrides:

writeObjectOverride in class ObjectOutputStream

Parameters:

obj - object to be written to the underlying stream

Throws:

IOException - if there are I/O errors while writing to the underlying stream

See Also:

ObjectOutputStream.ObjectOutputStream(), ObjectOutputStream.writeObject(Object)

writeUnshared

public void writeUnshared(Object obj)
                   throws IOException

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.

Overrides:

writeUnshared in class ObjectOutputStream

Parameters:

obj - object to write to stream

Throws:

InvalidClassException - if a problem exists with the class of an object to be serialized

IOException - if an I/O error occurs during serialization

write

public void write(int val)
           throws IOException

Writes a byte. This method will block until the byte is actually written.

Specified by:

write in interface DataOutput

Specified by:

write in interface ObjectOutput

Overrides:

write in class ObjectOutputStream

Parameters:

val - the byte to be written to the stream

Throws:

IOException - If an I/O error has occurred.

write

public void write(byte[] buf)
           throws IOException

Writes an array of bytes. This method will block until the bytes are actually written.

Specified by:

write in interface DataOutput

Specified by:

write in interface ObjectOutput

Overrides:

write in class ObjectOutputStream

Parameters:

buf - the data to be written

Throws:

IOException - If an I/O error has occurred.

See Also:

OutputStream.write(byte[], int, int)

write

public void write(byte[] buf,
                  int off,
                  int len)
           throws IOException

Writes a sub array of bytes.

Specified by:

write in interface DataOutput

Specified by:

write in interface ObjectOutput

Overrides:

write in class ObjectOutputStream

Parameters:

buf - the data to be written

off - the start offset in the data

len - the number of bytes that are written

Throws:

IOException - If an I/O error has occurred.

flush

public void flush()
           throws IOException

Flushes the stream. This will write any buffered output bytes and flush through to the underlying stream.

Specified by:

flush in interface Flushable

Specified by:

flush in interface ObjectOutput

Overrides:

flush in class ObjectOutputStream

Throws:

IOException - If an I/O error has occurred.

writeBoolean

public void writeBoolean(boolean val)
                  throws IOException

Writes a boolean.

Specified by:

writeBoolean in interface DataOutput

Overrides:

writeBoolean in class ObjectOutputStream

Parameters:

val - the boolean to be written

Throws:

IOException - if I/O errors occur while writing to the underlying stream

writeByte

public void writeByte(int val)
               throws IOException

Writes an 8 bit byte.

Specified by:

writeByte in interface DataOutput

Overrides:

writeByte in class ObjectOutputStream

Parameters:

val - the byte value to be written

Throws:

IOException - if I/O errors occur while writing to the underlying stream

writeShort

public void writeShort(int val)
                throws IOException

Writes a 16 bit short.

Specified by:

writeShort in interface DataOutput

Overrides:

writeShort in class ObjectOutputStream

Parameters:

val - the short value to be written

Throws:

IOException - if I/O errors occur while writing to the underlying stream

writeChar

public void writeChar(int val)
               throws IOException

Writes a 16 bit char.

Specified by:

writeChar in interface DataOutput

Overrides:

writeChar in class ObjectOutputStream

Parameters:

val - the char value to be written

Throws:

IOException - if I/O errors occur while writing to the underlying stream

writeInt

public void writeInt(int val)
              throws IOException

Writes a 32 bit int.

Specified by:

writeInt in interface DataOutput

Overrides:

writeInt in class ObjectOutputStream

Parameters:

val - the integer value to be written

Throws:

IOException - if I/O errors occur while writing to the underlying stream

writeLong

public void writeLong(long val)
               throws IOException

Writes a 64 bit long.

Specified by:

writeLong in interface DataOutput

Overrides:

writeLong in class ObjectOutputStream

Parameters:

val - the long value to be written

Throws:

IOException - if I/O errors occur while writing to the underlying stream

writeFloat

public void writeFloat(float val)
                throws IOException

Writes a 32 bit float.

Specified by:

writeFloat in interface DataOutput

Overrides:

writeFloat in class ObjectOutputStream

Parameters:

val - the float value to be written

Throws:

IOException - if I/O errors occur while writing to the underlying stream

writeDouble

public void writeDouble(double val)
                 throws IOException

Writes a 64 bit double.

Specified by:

writeDouble in interface DataOutput

Overrides:

writeDouble in class ObjectOutputStream

Parameters:

val - the double value to be written

Throws:

IOException - if I/O errors occur while writing to the underlying stream

writeBytes

public void writeBytes(String str)
                throws IOException

Writes a String as a sequence of bytes.

Specified by:

writeBytes in interface DataOutput

Overrides:

writeBytes in class ObjectOutputStream

Parameters:

str - the String of bytes to be written

Throws:

IOException - if I/O errors occur while writing to the underlying stream

writeChars

public void writeChars(String str)
                throws IOException

Writes a String as a sequence of chars.

Specified by:

writeChars in interface DataOutput

Overrides:

writeChars in class ObjectOutputStream

Parameters:

str - the String of chars to be written

Throws:

IOException - if I/O errors occur while writing to the underlying stream

writeUTF

public void writeUTF(String str)
              throws IOException

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.

Specified by:

writeUTF in interface DataOutput

Overrides:

writeUTF in class ObjectOutputStream

Parameters:

str - the String to be written

Throws:

IOException - if I/O errors occur while writing to the underlying stream

reset

public final void reset()
                 throws IOException

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.

Overrides:

reset in class ObjectOutputStream

Throws:

IOException - if reset() is invoked while serializing an object.

close

public final void close()
                 throws IOException

Closes the stream. This method must be called to release any resources associated with the stream.

Specified by:

close in interface Closeable

Specified by:

close in interface ObjectOutput

Overrides:

close in class ObjectOutputStream

Throws:

IOException - If an I/O error has occurred.

useProtocolVersion

public final void useProtocolVersion(int version)
                              throws IOException

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.

Overrides:

useProtocolVersion in class ObjectOutputStream

Parameters:

version - use ProtocolVersion from java.io.ObjectStreamConstants.

Throws:

IOException - if I/O errors occur

See Also:

ObjectStreamConstants.PROTOCOL_VERSION_1, ObjectStreamConstants.PROTOCOL_VERSION_2

annotateClass

protected final void annotateClass(Class<?> cl)
                            throws IOException

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.

Overrides:

annotateClass in class ObjectOutputStream

Parameters:

cl - the class to annotate custom data for

Throws:

IOException - Any exception thrown by the underlying OutputStream.

annotateProxyClass

protected final void annotateProxyClass(Class<?> cl)
                                 throws IOException

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.

Overrides:

annotateProxyClass in class ObjectOutputStream

Parameters:

cl - the proxy class to annotate custom data for

Throws:

IOException - any exception thrown by the underlying OutputStream

See Also:

ObjectInputStream.resolveProxyClass(String[])

replaceObject

protected final Object replaceObject(Object obj)
                              throws IOException

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.

Overrides:

replaceObject in class ObjectOutputStream

Parameters:

obj - the object to be replaced

Returns:

the alternate object that replaced the specified one

Throws:

IOException - Any exception thrown by the underlying OutputStream.

enableReplaceObject

protected final boolean enableReplaceObject(boolean enable)
                                     throws SecurityException

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.

Overrides:

enableReplaceObject in class ObjectOutputStream

Parameters:

enable - boolean parameter to enable replacement of objects

Returns:

the previous setting before this method was invoked

Throws:

SecurityException - if a security manager exists and its checkPermission method denies enabling the stream to do replacement of objects in the stream.

See Also:

SecurityManager.checkPermission(java.security.Permission), SerializablePermission

writeStreamHeader

protected final void writeStreamHeader()
                                throws IOException

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.

Overrides:

writeStreamHeader in class ObjectOutputStream

Throws:

IOException - if I/O errors occur while writing to the underlying stream

writeClassDescriptor

protected final void writeClassDescriptor(ObjectStreamClass desc)
                                   throws IOException

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.

Overrides:

writeClassDescriptor in class ObjectOutputStream

Parameters:

desc - class descriptor to write to the stream

Throws:

IOException - If an I/O error has occurred.

See Also:

ObjectInputStream.readClassDescriptor(), ObjectOutputStream.useProtocolVersion(int), ObjectStreamConstants.PROTOCOL_VERSION_1

drain

protected final void drain()
                    throws IOException

Drain any buffered data in ObjectOutputStream. Similar to flush but does not propagate the flush to the underlying stream.

Overrides:

drain in class ObjectOutputStream

Throws:

IOException - if I/O errors occur while writing to the underlying stream

writeFields

public abstract void writeFields()
                          throws IOException

Write the buffered fields to the stream.

Overrides:

writeFields in class ObjectOutputStream

Throws:

IOException - if I/O errors occur while writing to the underlying stream

NotActiveException - Called when a classes writeObject method was not called to write the state of the object.

putFields

public abstract ObjectOutputStream.PutField putFields()
                                               throws IOException

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.

Overrides:

putFields in class ObjectOutputStream

Returns:

an instance of the class Putfield that holds the serializable fields

Throws:

IOException - if I/O errors occur

defaultWriteObject

public abstract void defaultWriteObject()
                                 throws IOException

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.

Overrides:

defaultWriteObject in class ObjectOutputStream

Throws:

IOException - if I/O errors occur while writing to the underlying OutputStream