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Diffstat (limited to 'qpid/tools/src/java/qpid-qmf2/src/main/java/org/apache/qpid/qmf2/common/WorkQueue.java')
-rw-r--r-- | qpid/tools/src/java/qpid-qmf2/src/main/java/org/apache/qpid/qmf2/common/WorkQueue.java | 106 |
1 files changed, 106 insertions, 0 deletions
diff --git a/qpid/tools/src/java/qpid-qmf2/src/main/java/org/apache/qpid/qmf2/common/WorkQueue.java b/qpid/tools/src/java/qpid-qmf2/src/main/java/org/apache/qpid/qmf2/common/WorkQueue.java new file mode 100644 index 0000000000..75b4e5d855 --- /dev/null +++ b/qpid/tools/src/java/qpid-qmf2/src/main/java/org/apache/qpid/qmf2/common/WorkQueue.java @@ -0,0 +1,106 @@ +/* + * + * 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. + * + */ +package org.apache.qpid.qmf2.common; + +// Misc Imports +import java.util.concurrent.BlockingQueue; +import java.util.concurrent.LinkedBlockingQueue; +import java.util.concurrent.TimeUnit; + +/** + * This is an implementation of a QMF2 WorkQueue. In practice this is likely to be used by an Agent or Console. + * + * @author Fraser Adams + */ +public class WorkQueue +{ + /** + * Used to implement a thread safe queue of WorkItem objects + */ + private BlockingQueue<WorkItem> _workQueue = new LinkedBlockingQueue<WorkItem>(); + + /** + * Return the count of pending WorkItems that can be retrieved. + * @return the count of pending WorkItems that can be retrieved. + */ + public int size() + { + return _workQueue.size(); + } + + /** + * Obtains the next pending work item - blocking version + * + * @return the next pending work item, or null if none available. + */ + public WorkItem getNextWorkitem() + { + try + { + return _workQueue.take(); + } + catch (InterruptedException ie) + { + return null; + } + } + + /** + * Obtains the next pending work item - balking version + * + * @param timeout the timeout in seconds. If timeout = 0 it returns immediately with either a WorkItem or null + * @return the next pending work item, or null if none available. + */ + public WorkItem getNextWorkitem(long timeout) + { + try + { + return _workQueue.poll(timeout, TimeUnit.SECONDS); + } + catch (InterruptedException ie) + { + return null; + } + } + + /** + * Adds a WorkItem to the WorkQueue. + * + * @param item the WorkItem passed to the WorkQueue + */ + public void addWorkItem(WorkItem item) + { + // We wrap the blocking put() method in a loop "just in case" InterruptedException occurs + // if it does we retry the put otherwise we carry on, notify then exit. + while (true) + { + try + { + _workQueue.put(item); + break; + } + catch (InterruptedException ie) + { + continue; + } + } + } +} |