StreamMessage
object is used to send a stream of primitive types in the Java programming language. It is filled and read sequentially. It inherits from the Message
interface and adds a stream message body. Its 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 clearBody
is called, the body of the message is in write-only mode. After the first call to reset
has been made, the message body is in read-only mode. After a message has been sent, the client that sent it can retain and modify it without affecting the message that has been sent. The same message object can be sent multiple times. 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 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.
StreamMessage
objects 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 primitive's 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 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 a NullPointerException
.
@see javax.jms.Session#createStreamMessage()
@see javax.jms.BytesMessage
@see javax.jms.MapMessage
@see javax.jms.Message
@see javax.jms.ObjectMessage
@see javax.jms.TextMessage
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