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EDU.oswego.cs.dl.util.concurrent
public class: BoundedPriorityQueue [javadoc | source]

java.lang.Object
   EDU.oswego.cs.dl.util.concurrent.SemaphoreControlledChannel
      EDU.oswego.cs.dl.util.concurrent.BoundedPriorityQueue

All Implemented Interfaces:
    BoundedChannel

A heap-based priority queue, using semaphores for concurrency control. The take operation returns the least element with respect to the given ordering. (If more than one element is tied for least value, one of them is arbitrarily chosen to be returned -- no guarantees are made for ordering across ties.) Ordering follows the JDK1.2 collection conventions: Either the elements must be Comparable, or a Comparator must be supplied. Comparison failures throw ClassCastExceptions during insertions and extractions. The implementation uses a standard array-based heap algorithm, as described in just about any data structures textbook.

Put and take operations may throw ClassCastException if elements are not Comparable, or not comparable using the supplied comparator. Since not all elements are compared on each operation it is possible that an exception will not be thrown during insertion of non-comparable element, but will later be encountered during another insertion or extraction.

[ Introduction to this package. ]

Field Summary
protected final  Heap	heap_

Fields inherited from EDU.oswego.cs.dl.util.concurrent.SemaphoreControlledChannel:
putGuard_,  takeGuard_,  capacity_

Constructor:
public BoundedPriorityQueue() { this(DefaultChannelCapacity.get(), null); } Create a priority queue with the current default capacity and relying on natural ordering. *
public BoundedPriorityQueue(Comparator comparator) { this(DefaultChannelCapacity.get(), comparator); } Create a priority queue with the current default capacity and the given comparator *
public BoundedPriorityQueue(int capacity) { this(capacity, null); } Create a priority queue with the given capacity, and relying on natural ordering. *
public BoundedPriorityQueue(int capacity, Comparator cmp) throws IllegalArgumentException { super(capacity); heap_ = new Heap(capacity, cmp); } Create a priority queue with the given capacity and comparator Throws: IllegalArgumentException - if capacity less or equal to zero exception: IllegalArgumentException - if capacity less or equal to zero
public BoundedPriorityQueue(int capacity, Comparator cmp, Class semaphoreClass) throws IllegalArgumentException, NoSuchMethodException, SecurityException, InstantiationException, IllegalAccessException, InvocationTargetException { super(capacity, semaphoreClass); heap_ = new Heap(capacity, cmp); } Create a priority queue with the given capacity and comparator, using the supplied Semaphore class for semaphores. Throws: IllegalArgumentException - if capacity less or equal to zero NoSuchMethodException - If class does not have constructor that intializes permits SecurityException - if constructor information not accessible InstantiationException - if semaphore class is abstract IllegalAccessException - if constructor cannot be called InvocationTargetException - if semaphore constructor throws an exception exception: IllegalArgumentException - if capacity less or equal to zero exception: NoSuchMethodException - If class does not have constructor that intializes permits exception: SecurityException - if constructor information not accessible exception: InstantiationException - if semaphore class is abstract exception: IllegalAccessException - if constructor cannot be called exception: InvocationTargetException - if semaphore constructor throws an exception

Method from EDU.oswego.cs.dl.util.concurrent.BoundedPriorityQueue Summary:
extract,   insert,   peek

Methods from EDU.oswego.cs.dl.util.concurrent.SemaphoreControlledChannel:
capacity,   extract,   insert,   offer,   poll,   put,   size,   take

Methods from java.lang.Object:
clone,   equals,   finalize,   getClass,   hashCode,   notify,   notifyAll,   toString,   wait,   wait,   wait

Method from EDU.oswego.cs.dl.util.concurrent.BoundedPriorityQueue Detail:
protected Object extract() { return heap_.extract(); }
protected void insert(Object x) { heap_.insert(x); }
public Object peek() { return heap_.peek(); }