jrun.jms.core.message
Class ObjectMessageImpl

jrun.jms.core.message.ObjectMessageImpl

public final class ObjectMessageImpl

This class implements the ObjectMessage interface

An ObjectMessage is used to send a message that contains a serializable Java object. It inherits from Message and adds a body containing a single Java reference. Only Serializable Java objects can be used.

If a collection of Java objects must be sent, one of the collection classes provided in JDK 1.2 can be used.

When a client receives an ObjectMessage, it is in read-only mode. If a client attempts to write to the message at this point, a MessageNotWriteableException is thrown. If clearBody is called, the message can now be both read from and written to.

Version:

$Revision: 1.6 $ $Date: 2001/08/06 03:00:00 $

Author:

Jim Mourikis, Tim Anderson

See Also:

ObjectMessage

Constructor Summary

ObjectMessageImpl()
Construct a new ObjectMessage

Method Summary

void	clearBody() Clear out the message body.
java.lang.Object	clone() Clone an instance of this object
java.io.Serializable	getObject() Get the serializable object containing this message's data.
void	readExternal(java.io.ObjectInput in) Serialize in this message's data
void	setObject(java.io.Serializable object) Set the serializable object containing this message's data.
void	writeExternal(java.io.ObjectOutput out) Serialize out this message's data

Constructor Detail

ObjectMessageImpl

public ObjectMessageImpl()
                  throws javax.jms.JMSException

Construct a new ObjectMessage

Throws:

JMSException - if the message type can't be set

Method Detail

clone

public final java.lang.Object clone()
                             throws java.lang.CloneNotSupportedException

Clone an instance of this object

Returns:

a copy of this object

Throws:

java.lang.CloneNotSupportedException - if object or attributes aren't cloneable

writeExternal

public final void writeExternal(java.io.ObjectOutput out)
                         throws java.io.IOException

Serialize out this message's data

Parameters:

out - the stream to serialize out to

Throws:

java.io.IOException - if any I/O exceptions occurr

readExternal

public final void readExternal(java.io.ObjectInput in)
                        throws java.lang.ClassNotFoundException,
                               java.io.IOException

Serialize in this message's data

Parameters:

in - the stream to serialize in from

Throws:

java.lang.ClassNotFoundException - if the class for an object being restored cannot be found.

java.io.IOException - if any I/O exceptions occur

setObject

public final void setObject(java.io.Serializable object)
                     throws javax.jms.MessageFormatException,
                            javax.jms.MessageNotWriteableException

Set the serializable object containing this message's data. It is important to note that an ObjectMessage contains a snapshot of the object at the time setObject() is called - subsequent modifications of the object will have no affect on the ObjectMessage body.

Parameters:

object - the message's data

Throws:

MessageFormatException - if object serialization fails

MessageNotWriteableException - if the message is read-only

getObject

public final java.io.Serializable getObject()
                                     throws javax.jms.MessageFormatException

Get the serializable object containing this message's data. The default value is null.

Returns:

the serializable object containing this message's data

Throws:

MessageFormatException - if object deserialization fails

clearBody

public final void clearBody()
                     throws javax.jms.JMSException

Clear out the message body. Clearing a message's body does not clear its header values or property entries. If this message body was read-only, calling this method leaves the message body is in the same state as an empty body in a newly created message