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3.4. JMS MapMessage Types

Qpid supports the Java JMS MapMessage interface, which provides support for maps in messages. The following code shows how to send a MapMessage in Java JMS.

Example 3.5. Sending a Java JMS MapMessage

	import java.util.ArrayList;
	import java.util.HashMap;
	import java.util.List;
	import java.util.Map;

	import javax.jms.Connection;
	import javax.jms.Destination;
	import javax.jms.MapMessage;
	import javax.jms.MessageProducer;
	import javax.jms.Session;

	import java.util.Arrays;

	// !!! SNIP !!!

	MessageProducer producer = session.createProducer(queue);

	MapMessage m = session.createMapMessage();
	m.setIntProperty("Id", 987654321);
	m.setStringProperty("name", "Widget");
	m.setDoubleProperty("price", 0.99);

	List<String> colors = new ArrayList<String>();
	colors.add("red");
	colors.add("green");
	colors.add("white");
	m.setObject("colours", colors);

	Map<String,Double> dimensions = new HashMap<String,Double>();
	dimensions.put("length",10.2);
	dimensions.put("width",5.1);
	dimensions.put("depth",2.0);
	m.setObject("dimensions",dimensions);

	List<List<Integer>> parts = new ArrayList<List<Integer>>();
	parts.add(Arrays.asList(new Integer[] {1,2,5}));
	parts.add(Arrays.asList(new Integer[] {8,2,5}));
	m.setObject("parts", parts);

	Map<String,Object> specs = new HashMap<String,Object>();
	specs.put("colours", colors);
	specs.put("dimensions", dimensions);
	specs.put("parts", parts);
	m.setObject("specs",specs);

	producer.send(m);
	

The following table shows the datatypes that can be sent in a MapMessage, and the corresponding datatypes that will be received by clients in Python or C++.

Table 3.5. Java Datatypes in Maps

Java Datatype→ Python→ C++
booleanboolbool
shortint | longint16
intint | longint32
longint | longint64
floatfloatfloat
doublefloatdouble
java.lang.Stringunicodestd::string
java.util.UUIDuuidqpid::types::Uuid
java.util.Map[a]dictVariant::Map
java.util.ListlistVariant::List

[a] In Qpid, maps can nest. This goes beyond the functionality required by the JMS specification.