| 1 | /******************************************************************************* |
| 2 | * Copyright (c) 2009, 2010 Ericsson |
| 3 | * |
| 4 | * All rights reserved. This program and the accompanying materials are |
| 5 | * made available under the terms of the Eclipse Public License v1.0 which |
| 6 | * accompanies this distribution, and is available at |
| 7 | * http://www.eclipse.org/legal/epl-v10.html |
| 8 | * |
| 9 | * Contributors: |
| 10 | * Francois Chouinard - Initial API and implementation |
| 11 | *******************************************************************************/ |
| 12 | |
| 13 | package org.eclipse.linuxtools.tmf.request; |
| 14 | |
| 15 | import java.util.Comparator; |
| 16 | import java.util.concurrent.Executor; |
| 17 | import java.util.concurrent.ExecutorService; |
| 18 | import java.util.concurrent.Executors; |
| 19 | import java.util.concurrent.PriorityBlockingQueue; |
| 20 | |
| 21 | import org.eclipse.linuxtools.tmf.Tracer; |
| 22 | import org.eclipse.linuxtools.tmf.component.TmfThread; |
| 23 | import org.eclipse.linuxtools.tmf.request.ITmfDataRequest.ExecutionType; |
| 24 | |
| 25 | /** |
| 26 | * <b><u>TmfRequestExecutor</u></b> |
| 27 | * |
| 28 | * A simple, straightforward request executor. |
| 29 | */ |
| 30 | public class TmfRequestExecutor implements Executor { |
| 31 | |
| 32 | private final ExecutorService fExecutor; |
| 33 | private final String fExecutorName; |
| 34 | private final PriorityBlockingQueue<TmfThread> fRequestQueue = new PriorityBlockingQueue<TmfThread>(100, new Comparator<TmfThread>() { |
| 35 | @Override |
| 36 | public int compare(TmfThread o1, TmfThread o2) { |
| 37 | if (o1.getExecType() == o2.getExecType()) |
| 38 | return 0; |
| 39 | if (o1.getExecType() == ExecutionType.BACKGROUND) |
| 40 | return 1; |
| 41 | return -1; |
| 42 | } |
| 43 | }); |
| 44 | private TmfThread fCurrentRequest; |
| 45 | |
| 46 | // ------------------------------------------------------------------------ |
| 47 | // Constructors |
| 48 | // ------------------------------------------------------------------------ |
| 49 | |
| 50 | public TmfRequestExecutor() { |
| 51 | this(Executors.newSingleThreadExecutor()); |
| 52 | } |
| 53 | |
| 54 | public TmfRequestExecutor(ExecutorService executor) { |
| 55 | fExecutor = executor; |
| 56 | String canonicalName = fExecutor.getClass().getCanonicalName(); |
| 57 | fExecutorName = canonicalName.substring(canonicalName.lastIndexOf('.') + 1); |
| 58 | if (Tracer.isComponentTraced()) Tracer.trace(fExecutor + " created"); //$NON-NLS-1$ |
| 59 | } |
| 60 | |
| 61 | /** |
| 62 | * @return the number of pending requests |
| 63 | */ |
| 64 | public synchronized int getNbPendingRequests() { |
| 65 | return fRequestQueue.size(); |
| 66 | } |
| 67 | |
| 68 | /** |
| 69 | * @return the shutdown state (i.e. if it is accepting new requests) |
| 70 | */ |
| 71 | public synchronized boolean isShutdown() { |
| 72 | return fExecutor.isShutdown(); |
| 73 | } |
| 74 | |
| 75 | /** |
| 76 | * @return the termination state |
| 77 | */ |
| 78 | public synchronized boolean isTerminated() { |
| 79 | return fExecutor.isTerminated(); |
| 80 | } |
| 81 | |
| 82 | /** |
| 83 | * Stops the executor |
| 84 | */ |
| 85 | public synchronized void stop() { |
| 86 | if (fCurrentRequest != null) { |
| 87 | fCurrentRequest.cancel(); |
| 88 | } |
| 89 | |
| 90 | while ((fCurrentRequest = fRequestQueue.poll()) != null) { |
| 91 | fCurrentRequest.cancel(); |
| 92 | } |
| 93 | |
| 94 | fExecutor.shutdown(); |
| 95 | if (Tracer.isComponentTraced()) Tracer.trace(fExecutor + " terminated"); //$NON-NLS-1$ |
| 96 | } |
| 97 | |
| 98 | // ------------------------------------------------------------------------ |
| 99 | // Operations |
| 100 | // ------------------------------------------------------------------------ |
| 101 | |
| 102 | /* (non-Javadoc) |
| 103 | * @see java.util.concurrent.Executor#execute(java.lang.Runnable) |
| 104 | */ |
| 105 | @Override |
| 106 | public synchronized void execute(final Runnable requestThread) { |
| 107 | fRequestQueue.offer(new TmfThread(((TmfThread) requestThread).getExecType()) { |
| 108 | @Override |
| 109 | public void run() { |
| 110 | try { |
| 111 | requestThread.run(); |
| 112 | } finally { |
| 113 | scheduleNext(); |
| 114 | } |
| 115 | } |
| 116 | @Override |
| 117 | public void cancel() { |
| 118 | ((TmfThread) requestThread).cancel(); |
| 119 | } |
| 120 | }); |
| 121 | if (fCurrentRequest == null) { |
| 122 | scheduleNext(); |
| 123 | } |
| 124 | } |
| 125 | |
| 126 | /** |
| 127 | * Executes the next pending request, if applicable. |
| 128 | */ |
| 129 | protected synchronized void scheduleNext() { |
| 130 | if ((fCurrentRequest = fRequestQueue.poll()) != null) { |
| 131 | if (!isShutdown()) |
| 132 | fExecutor.execute(fCurrentRequest); |
| 133 | } |
| 134 | } |
| 135 | |
| 136 | // ------------------------------------------------------------------------ |
| 137 | // Object |
| 138 | // ------------------------------------------------------------------------ |
| 139 | |
| 140 | @Override |
| 141 | @SuppressWarnings("nls") |
| 142 | public String toString() { |
| 143 | return "[TmfRequestExecutor(" + fExecutorName + ")]"; |
| 144 | } |
| 145 | |
| 146 | } |