12 Dec 2015
LearningActiveMq_ActiveMQDestination_Hierarchy
Hierarchy benifits
###Hierarchy of ActiveMQDestion
Base enum variables encapsulated in ActiveMQDestination(super class), and usage in child class:
public abstract class ActiveMQDestination extends JNDIBaseStorable implements DataStructure, Destination, Externalizable, Comparable<Object> {
public static final String PATH_SEPERATOR = ".";
public static final char COMPOSITE_SEPERATOR = ',';
public static final byte QUEUE_TYPE = 0x01;
public static final byte TOPIC_TYPE = 0x02;
public static final byte TEMP_MASK = 0x04;
public static final byte TEMP_TOPIC_TYPE = TOPIC_TYPE | TEMP_MASK;
//using | to implement containing both conditions in byte enum
public static final byte TEMP_QUEUE_TYPE = QUEUE_TYPE | TEMP_MASK;
public static final String QUEUE_QUALIFIED_PREFIX = "queue://";
public static final String TOPIC_QUALIFIED_PREFIX = "topic://";
public static final String TEMP_QUEUE_QUALIFED_PREFIX = "temp-queue://";
public static final String TEMP_TOPIC_QUALIFED_PREFIX = "temp-topic://";
public static final String IS_DLQ = "isDLQ";
public static final String TEMP_DESTINATION_NAME_PREFIX = "ID:";
private static final long serialVersionUID = -3885260014960795889L;
protected String physicalName;
protected transient ActiveMQDestination[] compositeDestinations;
protected transient String[] destinationPaths;
protected transient boolean isPattern;
protected transient int hashValue;
protected Map<String, String> options;
}
...
####Static method for creating new ActiveMQDestination and its child classes based on two params
public static ActiveMQDestination createDestination(String name, byte defaultType) {
if (name.startsWith(QUEUE_QUALIFIED_PREFIX)) {
return new ActiveMQQueue(name.substring(QUEUE_QUALIFIED_PREFIX.length()));
} else if (name.startsWith(TOPIC_QUALIFIED_PREFIX)) {
return new ActiveMQTopic(name.substring(TOPIC_QUALIFIED_PREFIX.length()));
} else if (name.startsWith(TEMP_QUEUE_QUALIFED_PREFIX)) {
return new ActiveMQTempQueue(name.substring(TEMP_QUEUE_QUALIFED_PREFIX.length()));
} else if (name.startsWith(TEMP_TOPIC_QUALIFED_PREFIX)) {
return new ActiveMQTempTopic(name.substring(TEMP_TOPIC_QUALIFED_PREFIX.length()));
}
switch (defaultType) {
case QUEUE_TYPE:
return new ActiveMQQueue(name);
case TOPIC_TYPE:
return new ActiveMQTopic(name);
case TEMP_QUEUE_TYPE:
return new ActiveMQTempQueue(name);
case TEMP_TOPIC_TYPE:
return new ActiveMQTempTopic(name);
default:
throw new IllegalArgumentException("Invalid default destination type: " + defaultType);
}
}
###getDestinationType() is override by its child class then using switch to distinguish which ActiveMQDestination it is
public abstract byte getDestinationType();
###This method is in ActiveMQDestination and inherited by all its child classes
public String getDestinationTypeAsString() {
switch (getDestinationType()) {
case QUEUE_TYPE:
return "Queue";
case TOPIC_TYPE:
return "Topic";
case TEMP_QUEUE_TYPE:
return "TempQueue";
case TEMP_TOPIC_TYPE:
return "TempTopic";
default:
throw new IllegalArgumentException("Invalid destination type: " + getDestinationType());
}
}
###ActiveMQTempDestination contains ActiveMQConnection, which can be used to remove this destination
public abstract class ActiveMQTempDestination extends ActiveMQDestination {
...
protected transient ActiveMQConnection connection;
...
public void delete() throws JMSException {
if (connection != null) {
connection.deleteTempDestination(this);
}
}
...
ActiveMQTempTopic extends ActiveMQTempDestination implements TemporaryTopic, ActiveMQTempTopic contains delete() method, which is not implemented by ActiveMQTempTopic, but it is inherit directly from ActiveMQTempDestination
Learning travel～
2015-12-12
xule
