If you haven't already, jump to the blog HOW TO: Create a Oracle AQ Topic JMS message for java delivery, which will be able to assist you in setting up the database, if you haven't already.

Java Message Service (JMS) is the messaging standard to provide the exchanging of messages. Essentially, JMS are a set interfaces that provides a JMS client the ability to facilitate for the enterprise messaging. This also includes the extension to support the operations and features for Advanced Queuing (AQ)

The JMS Text message is sent to an AQ queue. There are other types of JMS messages ('bytes_messages', 'map_message', 'stream_message' etc) though this blog focuses on the text message, which is called SYS.AQ$_JMS_TEXT_MESSAGE.

The code below goes through a similar example though here's a basic JMS TEXT MESSAGE.

SYS.AQ$_JMS_TEXT_MESSAGE(
SYS.AQ$_JMS_HEADER(NULL,NULL,NULL,NULL,NULL,NULL,NULL),
17,
'text',
NULL
)

Essentially, the SYS.AQ$_JMS_TEXT_MESSAGE as 4 components, which are highlighted below. the type of JMS_TEXT_MESSAGE components are as follows:

• HEADER - Header properties in the SYS.AQ$_JMS_HEADER datatype. (Explained in more detail below)
• TEXT_LEN - It's the size of the message, which it is set automatically. The example above is 29
• TEXT_VC - The message payload in VARCHAR2 format, if the payload is equal to or less than 4000 bytes. Because the example above is TEXT_LEN is less than 4000 (hence 29), this is populated and not the TEXT_LOB. If it's greater than 4000, this remains null and the TEXT_LOB is populated.
• TEXT_LOB - The message payload in CLOB (hence the 'LOB' name) format. This is populated if the TEXT_VS is greater than 4000, otherwise it's null

The HEADER value, which is known as the SYS.AQ$_JMS_HEADER datatype, contains the following attributes.

• REPLYTO - A Destination supplied by a client when a message is sent
• TYPE - The type of the message
• USERID - The identity of the user sending the message
• APPID - The identity of the application sending the message
• GROUPID - The identity of the message group of which this message is a part; set by the client
• GROUPSEQ - The sequence number of the message within the group
• PROPERTIES - Additional message properties in the SYS.AQ$_JMS_USERPROPARRAY datatype

Example Below:

package com.aptec.iam.idl.client.produceMessage;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.sql.SQLException;
import java.util.Properties;

import javax.jms.JMSException;
import javax.jms.MessageProducer;
import javax.jms.Queue;
import javax.jms.QueueConnection;
import javax.jms.QueueConnectionFactory;
import javax.jms.Session;
import javax.jms.TextMessage;
import javax.jms.TopicConnection;
import javax.naming.InitialContext;

import oracle.jms.AQjmsFactory;
import oracle.jms.AQjmsSession;

public class OracleAQClient {

	static final String xmlFile = "/Users/danielredfern/Documents/workspace/AQProducerAndConsumer/src/com/aptec/iam/idl/client/xmlExamples/identification.xml";
	
	
public static QueueConnection getConnection() {

	
	Properties p = new Properties();
	p.setProperty("java.naming.factory.initial", "weblogic.jndi.WLInitialContextFactory");
	p.setProperty("java.naming.provider.url", "t3://172.16.101.253:7001");
	p.setProperty("java.naming.security.principal", "weblogic");
	p.setProperty("java.naming.security.credentials", "Password1");
	
	InitialContext ctx = null;
	
	try{
		
		ctx = new InitialContext(p);
	}catch(Exception e){
		e.printStackTrace();
	}
	
    String hostname = "172.16.101.253";
    String oracle_sid = "orcl";
    int portno = 1521;
    String userName = "ORACLEAQJMSUSER";
    String password = "ORACLEAQJMSUSER";
    String driver = "thin";
    QueueConnectionFactory QFac = null;
    QueueConnection QCon = null;
    try {
        // get connection factory , not going through JNDI here
        QFac = AQjmsFactory.getQueueConnectionFactory(hostname, oracle_sid, portno, driver);
        // create connection
        QCon = QFac.createQueueConnection(userName, password);
    } catch (Exception e) {
        e.printStackTrace();
    }
    return QCo

The identification.xml file contains characters that exceeds 4000 characters, so the VC becomes a BLOB. This is demonstrated when I query queue table, by using the following command:

select msgid, enq_time, enq_uid, q.user_data from queuetable1 q where q_name = 'AQ_MESSAGE_QUEUE_TABLE'

About the author