CODEWITHSUNDEEP
javaibm-mq
Samyak Parakh
Samyak Parakh

Reputation: 11

how to read MQ messages using java without deleting message from the queue

When I execute my below code, it will read data from MQ on the console and then delete all the data from the queue. I don't want my data to be deleted from the queue while reading from MQ. I want to make it parameterize and also wants to write the data to excel. Can anybody please help me out from this. Below is my code that I am using.

public class MQReadJava
{
    private MQQueueManager _queueManager = null;
    public int port = 1416;
    public String hostname = "xyz";
    public String channel = "SYSTEM.ABC.123";
    public String qManager = "ABC.BAW";
    public String inputQName = "MYQUEUE";

    public MQReadJava()
    {
        super(); 
    }

    private void init(String[] args) throws IllegalArgumentException
    {
        // Set up MQ environment

        MQEnvironment.hostname = hostname;
        MQEnvironment.channel = channel;
        MQEnvironment.port = port;
    }

    public static void main(String[] args)throws IllegalArgumentException
    {
        MQReadJava readQ = new MQReadJava();
        try
        {
            readQ.init(args);
            readQ.selectQMgr();
            readQ.read();
        }

        catch (IllegalArgumentException e)
        {
            System.exit(1);
        }
        catch (MQException e)
        {
            System.out.println(e);
            System.exit(1);
        }
    }

    private void selectQMgr() throws MQException
    {
        _queueManager = new MQQueueManager(qManager);
    }

    private void read() throws MQException
    {
        int openOptions = MQC.MQOO_INQUIRE + MQC.MQOO_FAIL_IF_QUIESCING + MQC.MQOO_INPUT_SHARED;

        //int   openOptions = MQC.MQOO_INPUT_AS_Q_DEF | MQC.MQOO_FAIL_IF_QUIESCING;

        MQQueue queue = _queueManager.accessQueue( inputQName,
        openOptions,
        null, // default q manager
        null, // no dynamic q name
        null ); // no alternate user id

        System.out.println("MQRead is now connected.\n");
        int depth = queue.getCurrentDepth();
        System.out.println("Current depth: " + depth + "\n");

        if (depth == 0)
        {
            return;
        }

        MQGetMessageOptions getOptions = new MQGetMessageOptions();
        getOptions.options = MQC.MQGMO_NO_WAIT + MQC.MQGMO_FAIL_IF_QUIESCING + 
        MQC.MQGMO_CONVERT;

        while(true)
        {
            MQMessage message = new MQMessage();
            try
            {
                queue.get(message, getOptions);
                byte[] b = new byte[message.getMessageLength()];
                message.readFully(b);
                System.out.println(new String(b));
                message.clearMessage();
            }
            catch (IOException e)
            {
                System.out.println("IOException during GET: " + e.getMessage());
                break;
            }
            catch (MQException e)
            {
                if (e.completionCode == 2 && e.reasonCode == MQException.MQRC_NO_MSG_AVAILABLE) {
                    if (depth > 0)
                    {
                        System.out.println("All messages read.");
                    }
                }
                else
                {
                    System.out.println("GET Exception: " + e);
                }
                break;
            }
        }
        queue.close();
        _queueManager.disconnect();
    }
}

Upvotes: 1

Views: 20434

Answers (2)

Roger
Roger

Reputation: 7456

Below is my code that I am using.

:) You downloaded my MQRead program. If you don't want it to do a destructive MQGET then you need to update the code to do a browse (see JoshMc's comments). Why didn't you download my MQBrowse program? Finally, please start reading the MQ Knowledge Center as it contains lots & lots of information for beginners to IBM MQ.

Update: You should not use MQEnvironment class as it is not thread safe. Put the connection information in a Hashtable. See here for an example: Java program to connect WMQ with User Id instead of channel

Upvotes: 5

JoshMc
JoshMc

Reputation: 10642

In order to not delete messages from the queue you need to browse the queue, this would be accomplished by updating your openOptions and getOptions as follows:

int openOptions = MQC.MQOO_INQUIRE + MQC.MQOO_FAIL_IF_QUIESCING +  MQC.MQOO_BROWSE;

and

getOptions.options = MQC.MQGMO_NO_WAIT + MQC.MQGMO_FAIL_IF_QUIESCING + MQC.MQGMO_CONVERT + MQC.MQGMO_BROWSE_NEXT;

Checkout this great list of sample IBM MQ Classes for Java applications on Capitalware's website: Sample IBM MQ Java Code

Upvotes: 2

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