/* (non-Javadoc)
* @see flap.messaging.IMessageQueue#isEmpty()
*/
@Override
public final boolean isEmpty() {
for (MessagePriority priority : MessagePriority.values())
if (!messageQueues.get(priority).isEmpty()) return false;
return true;
}
/**
* Provides the total amount of messages waiting to be processed, without any regard to the
* priority of each message.
*
* @return the total number of not-yet-processed messages
*/
public final int getQueueLength() {
int sum = 0;
for (MessagePriority priority : MessagePriority.values())
sum += getQueueLengthByPriority(priority);
return sum;
}
/** Default constructor. Creates all the message queues. */
public MessageQueue() {
super();
// init the message queue container
messageQueues = new HashMap<MessagePriority, List<Message>>();
// create all the message queues
for (MessagePriority priority : MessagePriority.values())
messageQueues.put(priority, new LinkedList<Message>());
}
/**
* Provides the next method to be processed. The method scans each priority queue in order to find
* the first not-null message and removes it from the queue returning it. The side effect is that
* the message is no more into the queue. If no message is found at any priority level, than null
* is returned.
*
* @return the next message to process or null if none
*/
public synchronized Message getNextMessage() {
for (MessagePriority priority : MessagePriority.values()) {
List<Message> currentQueue = messageQueues.get(priority);
if (!currentQueue.isEmpty()) {
// get the head and remove it from the list
Message currentMessage = currentQueue.remove(0);
// this is the next message to be processed
return currentMessage;
}
}
// if here no message has been found in any priority queue
return null;
}