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Diffstat (limited to 'qpid/java/common/src/main/java/org/apache/qpid/util/concurrent/BatchSynchQueue.java')
-rw-r--r-- | qpid/java/common/src/main/java/org/apache/qpid/util/concurrent/BatchSynchQueue.java | 122 |
1 files changed, 0 insertions, 122 deletions
diff --git a/qpid/java/common/src/main/java/org/apache/qpid/util/concurrent/BatchSynchQueue.java b/qpid/java/common/src/main/java/org/apache/qpid/util/concurrent/BatchSynchQueue.java deleted file mode 100644 index 63d8f77edb..0000000000 --- a/qpid/java/common/src/main/java/org/apache/qpid/util/concurrent/BatchSynchQueue.java +++ /dev/null @@ -1,122 +0,0 @@ -package org.apache.qpid.util.concurrent; -/* - * - * Licensed to the Apache Software Foundation (ASF) under one - * or more contributor license agreements. See the NOTICE file - * distributed with this work for additional information - * regarding copyright ownership. The ASF licenses this file - * to you 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. - * - */ - - -import java.util.Collection; -import java.util.concurrent.BlockingQueue; - -/** - * BatchSynchQueue is an abstraction of the classic producer/consumer buffer pattern for thread interaction. In this - * pattern threads can deposit data onto a buffer whilst other threads take data from the buffer and perform usefull - * work with it. A BatchSynchQueue adds to this the possibility that producers can be blocked until their data is - * consumed or until a consumer chooses to release the producer some time after consuming the data from the queue. - * - * <p>There are a number of possible advantages to using this technique when compared with having the producers - * processing their own data: - * - * <ul> - * <li>Data may be deposited asynchronously in the buffer allowing the producers to continue running.</li> - * <li>Data may be deposited synchronously in the buffer so that producers wait until their data has been processed - * before being allowed to continue.</li> - * <li>Variable rates of production/consumption can be smoothed over by the buffer as it provides space in memory to - * hold data between production and consumption.</li> - * <li>Consumers may be able to batch data as they consume it leading to more efficient consumption over - * individual data item consumption where latency associated with the consume operation can be ammortized. - * For example, it may be possibly to ammortize the cost of a disk seek over many producers.</li> - * <li>Data from seperate threads can be combined together in the buffer, providing a convenient way of spreading work - * amongst many workers and gathering the results together again.</li> - * <li>Different types of queue can be used to hold the buffer, resulting in different processing orders. For example, - * lifo, fifo, priority heap, etc.</li> - * </ul> - * - * <p/>The asynchronous type of producer/consumer buffers is already well supported by the java.util.concurrent package - * (in Java 5) and there is also a synchronous queue implementation available there too. This interface extends the - * blocking queue with some more methods for controlling a synchronous blocking queue. In particular it adds additional - * take methods that can be used to take data from a queue without releasing producers, so that consumers have an - * opportunity to confirm correct processing of the data before producers are released. It also adds a put method with - * exceptions so that consumers can signal exception cases back to producers where there are errors in the data. - * - * <p/>This type of queue is usefull in situations where consumers can obtain an efficiency gain by batching data - * from many threads but where synchronous handling of that data is neccessary because producers need to know that - * their data has been processed before they continue. For example, sending a bundle of messages together, or writing - * many records to disk at once, may result in improved performance but the originators of the messages or disk records - * need confirmation that their data has really been sent or saved to disk. - * - * <p/>The consumer can put an element back onto the queue or send an error message to the elements producer using the - * {@link SynchRecord} interface. - * - * <p/>The {@link #take()}, {@link #drainTo(java.util.Collection<? super E>)} and - * {@link #drainTo(java.util.Collection<? super E>, int)} methods from {@link BlockingQueue} should behave as if they - * have been called with unblock set to false. That is they take elements from the queue but leave the producers - * blocked. These methods do not return collections of {@link SynchRecord}s so they do not supply an interface through - * which errors or re-queuings can be applied. If these methods are used then the consumer must succesfully process - * all the records it takes. - * - * <p/>The {@link #put} method should silently swallow any exceptions that consumers attempt to return to the caller. - * In order to handle exceptions the {@link #tryPut} method must be used. - * - * <p/><table id="crc"><caption>CRC Card</caption> - * <tr><th> Responsibilities <th> Collaborations - * <tr><td> Handle synchronous puts, with possible exceptions. - * <tr><td> Allow consumers to take many records from a queue in a batch. - * <tr><td> Allow consumers to decide when to unblock synchronous producers. - * </table> - */ -public interface BatchSynchQueue<E> extends BlockingQueue<E> -{ - /** - * Tries a synchronous put into the queue. If a consumer encounters an exception condition whilst processing the - * data that is put, then this is returned to the caller wrapped inside a {@link SynchException}. - * - * @param e The data element to put into the queue. - * - * @throws InterruptedException If the thread is interrupted whilst waiting to write to the queue or whilst waiting - * on its entry in the queue being consumed. - * @throws SynchException If a consumer encounters an error whilst processing the data element. - */ - public void tryPut(E e) throws InterruptedException, SynchException; - - /** - * Takes all available data items from the queue or blocks until some become available. The returned items - * are wrapped in a {@link SynchRecord} which provides an interface to requeue them or send errors to their - * producers, where the producers are still blocked. - * - * @param c The collection to drain the data items into. - * @param unblock If set to <tt>true</tt> the producers for the taken items will be immediately unblocked. - * - * @return A count of the number of elements that were drained from the queue. - */ - public SynchRef drainTo(Collection<SynchRecord<E>> c, boolean unblock); - - /** - * Takes up to maxElements available data items from the queue or blocks until some become available. The returned - * items are wrapped in a {@link SynchRecord} which provides an interface to requeue them or send errors to their - * producers, where the producers are still blocked. - * - * @param c The collection to drain the data items into. - * @param maxElements The maximum number of elements to drain. - * @param unblock If set to <tt>true</tt> the producers for the taken items will be immediately unblocked. - * - * @return A count of the number of elements that were drained from the queue. - */ - public SynchRef drainTo(Collection<SynchRecord<E>> c, int maxElements, boolean unblock); -} |