- /*
- * Copyright 2003-2004 The Apache Software Foundation
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
- package org.apache.commons.collections.buffer;
-
- import java.util.Collection;
-
- import org.apache.commons.collections.Buffer;
- import org.apache.commons.collections.BufferUnderflowException;
-
- /**
- * Decorates another <code>Buffer</code> to make {@link #get()} and
- * {@link #remove()} block when the <code>Buffer</code> is empty.
- * <p>
- * If either <code>get</code> or <code>remove</code> is called on an empty
- * <code>Buffer</code>, the calling thread waits for notification that
- * an <code>add</code> or <code>addAll</code> operation has completed.
- * <p>
- * When one or more entries are added to an empty <code>Buffer</code>,
- * all threads blocked in <code>get</code> or <code>remove</code> are notified.
- * There is no guarantee that concurrent blocked <code>get</code> or
- * <code>remove</code> requests will be "unblocked" and receive data in the
- * order that they arrive.
- * <p>
- * This class is Serializable from Commons Collections 3.1.
- *
- * @since Commons Collections 3.0
- * @version $Revision: 1.7 $ $Date: 2004/06/03 22:02:13 $
- *
- * @author Stephen Colebourne
- * @author Janek Bogucki
- * @author Phil Steitz
- */
- public class BlockingBuffer extends SynchronizedBuffer {
-
- /** Serialization version */
- private static final long serialVersionUID = 1719328905017860541L;
-
- /**
- * Factory method to create a blocking buffer.
- *
- * @param buffer the buffer to decorate, must not be null
- * @return a new blocking Buffer
- * @throws IllegalArgumentException if buffer is null
- */
- public static Buffer decorate(Buffer buffer) {
- return new BlockingBuffer(buffer);
- }
-
- //-----------------------------------------------------------------------
- /**
- * Constructor that wraps (not copies).
- *
- * @param buffer the buffer to decorate, must not be null
- * @throws IllegalArgumentException if the buffer is null
- */
- protected BlockingBuffer(Buffer buffer) {
- super(buffer);
- }
-
- //-----------------------------------------------------------------------
- public boolean add(Object o) {
- synchronized (lock) {
- boolean result = collection.add(o);
- notifyAll();
- return result;
- }
- }
-
- public boolean addAll(Collection c) {
- synchronized (lock) {
- boolean result = collection.addAll(c);
- notifyAll();
- return result;
- }
- }
-
- public Object get() {
- synchronized (lock) {
- while (collection.isEmpty()) {
- try {
- wait();
- } catch (InterruptedException e) {
- throw new BufferUnderflowException();
- }
- }
- return getBuffer().get();
- }
- }
-
- public Object remove() {
- synchronized (lock) {
- while (collection.isEmpty()) {
- try {
- wait();
- } catch (InterruptedException e) {
- throw new BufferUnderflowException();
- }
- }
- return getBuffer().remove();
- }
- }
-
- }