PriorityBlockingQueue

The 

PriorityBlockingQueue

 class implements the 

BlockingQueue

 interface.
Read the 

BlockingQueue

 text for more information about
the interface.

The 

PriorityBlockingQueue

 is an unbounded concurrent queue. It uses the same ordering rules as the

java.util.PriorityQueue

 class. You cannot insert null into this queue.

All elements inserted into the 

PriorityBlockingQueue

 must implement the 

java.lang.Comparable

 interface. The elements thus order themselves according to whatever priority you decide in your 

Comparable

implementation.

Notice that the 

PriorityBlockingQueue

 does not enforce any specific behaviour for elements that have equal priority (compare() == 0).

Also notice, that in case you obtain an 

Iterator

 from a 

PriorityBlockingQueue

, the 

Iterator

 does not guarantee to iterate the elements in priority order.

Here is an example of how to use the 

PriorityBlockingQueue

:

BlockingQueue queue   = new PriorityBlockingQueue();

//String implements java.lang.Comparable
queue.put("Value");

String value = queue.take();