Message Streaming

• Extensions to WmMessageProducer, which has methods to get the output stream object. In the message stream, there is a method to write data to the message producer.
• Extension to WmMessageConsumer, which has a method to get the input stream object. In the message stream, there is a method to read data from a message consumer.

Implementation of the streaming API introduces two new classes: WmJMSInputStream and WmJMSOutputStream. These classes extend the java.io.InputStream and java.io.OutputStream classes, and are returned by WmMessageConsumer.getInputStream() and WmMessageProducer.getOutputStream().

The WmJMSOutputStream class streams data written to it by packaging the data into 1 Mb chunks and sending the data to the message producer's destination using a JMS BytesMessage. The quality of service (persistent or non-persistent), along with priority and expiration, will be the same as those set for the message producer. The WmJMSInputStream class asynchronously receives the BytesMessages and makes the data available when the stream is read.

Once the WmJMSOutputStream is closed, a final BytesMessage is sent with the provider-specific Boolean property JMS_WM_END_OF_STREAMset to true. When this is received by the WmJMSInputStream class, it will return -1 from read() to indicate that the end of the stream has been reached.

• Interfaces to IMessageProducer, which has a method returning class MsgOutputStream. You can use the class to write data.
• Interfaces to IMessageConsumer, which has a method to read data from the class MsgInputStream.

Implementation of the streaming API introduces two new classes: MsgInputStream and MsgOutputStream. These extend the stream class and are returned by IMessageConsumer.getInputStream() and IMessageConsumer.getOutputStream().

The MsgOutputStream class streams data written to it by packaging the data and sending it to the message producer's destination using a BytesMessage. The quality of service (persistent or non-persistent), along with priority and expiration, will be the same as those set for the message producer. The MsgInputStream class asynchronously receives the BytesMessages and makes the data available when the stream is read.

Once the MsgOutputStream is closed, a final BytesMessage is sent with the provider-specific Boolean property JMS_WM_END_OF_STREAM set to true. When this is received by the MsgInputStream class, it will return 0 from read() indicating that the end of the stream has been reached.

For WmJMSInputStream:

public  void  markStreamBytePosition (int pos)  
public  int   currentReadBytePosition ()

For WmJMSOutputStream:

public  void  markStreamBytePosition (int pos)  
public  int   currentWrittenBytePosition ()

public  Long Position ()  
{  
   set;  
   get;  
}

On the message consumer side, if the user specified CLIENT_ACKNOWLEDGE during session creation, all of the messages will be acknowledged when the input stream is closed.

For additional information about specifying the location in a stream, see Technical Considerations.

// Create a non-transacted session.  
Session sess = connection.createSession(false, Session.AUTO_ACKNOWLEDGE)  
    
// Create a message consumer.  
MessageConsumer consumer = sess.createConsumer(topic);  
    
// Wrap the message consumer’s input stream in an audio stream.  
AudioStream as = new AudioStream(as);  
    
// Start the audio player.  
AudioPlayer.player.start(as);

// Create a non-transacted session.  
Session sess = connection.createSession(false, Session.AUTO_ACKNOWLEDGE)  
    
// Create a message consumer.  
IMessageConsumer consumer = sess.createConsumer(topic);  
MsgInputStream consumer is = consumer.getInputStream();  
    
// Wrap the message consumer’s input stream in an audio stream.  
AudioStream as = new AudioStream(as);  
    
// Start the audio player.  
AudioPlayer.player.start(as);