Groovy script to connect to an ActiveMQ server and receive messages from the default Dead Letter Queue

activemq_dlq.groovy

#!/bin/groovy

// NOTE: The jar "activemq-all-5.15.8.jar" needs to be put under $HOME/.groovy/lib
//       for this script to work

import javax.jms.*
import org.apache.activemq.*

def amqURL = "failover:tcp://localhost:61616"
println "Connecting to ActiveMQ at URL " + amqURL
def connFactory = new ActiveMQConnectionFactory(amqURL)
def conn = connFactory.createConnection()
conn.start()

println "Creating session"
def session = conn.createSession(true, ActiveMQSession.CLIENT_ACKNOWLEDGE)
def dest = session.createQueue("ActiveMQ.DLQ")

def consumer = session.createConsumer(dest)
def duplicateLineIDCount = 0;
def otherDLQMessageCount = 0;
println("Waiting for messages...");
while(true) {
  msg = consumer.receive();
  //println "Received message " + msg.toString()
  if( msg instanceof  TextMessage ) {
    if(msg.getProperty("dlqDeliveryFailureCause") && msg.getProperty("dlqDeliveryFailureCause").indexOf("NonUniqueResultException: Unique expecting 0 or 1 results but got") > 0){
      println "Got duplicate LineID message with values: " + msg.getText()
      msg.acknowledge()
      session.commit()
      duplicateLineIDCount++
    }
    else {
      println "#------------------#"
      println "Got an unfamiliar DLQ messge: " + msg
      println "#------------------#"
      session.rollback()
      otherDLQMessageCount++
    }
  }
  println "Total Duplicate Line ID: " + duplicateLineIDCount + ", total Other DLQ Messages: " + otherDLQMessageCount
}