A StreamMessage is used to send a stream of Java primitives. It is filled and read sequentially. It inherits from Message and adds a stream message body. It's methods are based largely on those found in java.io.DataInputStream and java.io.DataOutputStream.
The primitive types can be read or written explicitly using methods for each type. They may also be read or written generically as objects. For instance, a call to StreamMessage.writeInt(6) is equivalent to StreamMessage.writeObject(new Integer(6)). Both forms are provided because the explicit form is convenient for static programming and the object form is needed when types are not known at compile time.
When the message is first created, and when {@link #clearBody}is called, the body of the message is in write-only mode. After the first call to {@link #reset} has been made, the message body is inread-only mode. When a message has been sent, by definition, the provider calls reset in order to read it's content, and when a message has been received, the provider has called reset so that the message body is in read-only mode for the client.
If {@link #clearBody} is called on a message in read-only mode,the message body is cleared and the message body is in write-only mode.
If a client attempts to read a message in write-only mode, a MessageNotReadableException is thrown.
If a client attempts to write a message in read-only mode, a MessageNotWriteableException is thrown.
Stream messages support the following conversion table. The marked cases must be supported. The unmarked cases must throw a JMSException. The String to primitive conversions may throw a runtime exception if the primitives valueOf() method does not accept it as a valid String representation of the primitive.
A value written as the row type can be read as the column type.
| | boolean byte short char int long float double String byte[] |---------------------------------------------------------------------- |boolean | X X |byte | X X X X X |short | X X X X |char | X X |int | X X X |long | X X |float | X X X |double | X X |String | X X X X X X X X |byte[] | X |----------------------------------------------------------------------
Attempting to read a null value as a Java primitive type must be treated as calling the primitive's corresponding valueOf(String) conversion method with a null value. Since char does not support a String conversion, attempting to read a null value as a char must throw NullPointerException.
@version $Revision: 1.2 $ $Date: 2005/05/24 13:27:10 $
@author Jim Mourikis
@author Tim Anderson
@see javax.jms.StreamMessage
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