org.eclipse.tracecompass.tmf.core/src/org/eclipse/linuxtools/tmf/core/signal/TmfSignalManager.java

   1 /*******************************************************************************
   2  * Copyright (c) 2009, 2014 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  *   Bernd Hufmann - Update register methods
  12  *******************************************************************************/
  13
  14 package org.eclipse.linuxtools.tmf.core.signal;
  15
  16 import java.lang.reflect.InvocationTargetException;
  17 import java.lang.reflect.Method;
  18 import java.util.ArrayList;
  19 import java.util.HashMap;
  20 import java.util.List;
  21 import java.util.Map;
  22 import java.util.concurrent.ExecutorService;
  23 import java.util.concurrent.Executors;
  24
  25 import org.eclipse.linuxtools.internal.tmf.core.Activator;
  26 import org.eclipse.linuxtools.internal.tmf.core.TmfCoreTracer;
  27
  28 /**
  29  * This class manages the set of signal listeners and the signals they are
  30  * interested in. When a signal is broadcasted, the appropriate listeners
  31  * signal handlers are invoked.
  32  *
  33  * @version 1.0
  34  * @author Francois Chouinard
  35  */
  36 public class TmfSignalManager {
  37
  38     // The set of event listeners and their corresponding handler methods.
  39     // Note: listeners could be restricted to ITmfComponents but there is no
  40     // harm in letting anyone use this since it is not tied to anything but
  41     // the signal data type.
  42     private static Map<Object, Method[]> fListeners = new HashMap<>();
  43     private static Map<Object, Method[]> fVIPListeners = new HashMap<>();
  44
  45     // The signal executor for asynchronous signals
  46     private static final ExecutorService fExecutor = Executors.newSingleThreadExecutor();
  47
  48     // If requested, add universal signal tracer
  49     // TODO: Temporary solution: should be enabled/disabled dynamically
  50     private static boolean fTraceIsActive = false;
  51     private static TmfSignalTracer fSignalTracer;
  52
  53     static {
  54         if (fTraceIsActive) {
  55             fSignalTracer = TmfSignalTracer.getInstance();
  56             register(fSignalTracer);
  57         }
  58     }
  59
  60     /**
  61      * Register an object to the signal manager. This object can then implement
  62      * handler methods, marked with @TmfSignalHandler and with the expected
  63      * signal type as parameter.
  64      *
  65      * @param listener
  66      *            The object that will be notified of new signals
  67      */
  68     public static synchronized void register(Object listener) {
  69         deregister(listener); // make sure that listener is only registered once
  70         Method[] methods = getSignalHandlerMethods(listener);
  71         if (methods.length > 0) {
  72             fListeners.put(listener, methods);
  73         }
  74     }
  75
  76     /**
  77      * Register an object to the signal manager as a "VIP" listener. All VIP
  78      * listeners will all receive the signal before the manager moves on to the
  79      * lowly, non-VIP listeners.
  80      *
  81      * @param listener
  82      *            The object that will be notified of new signals
  83      */
  84     public static synchronized void registerVIP(Object listener) {
  85         deregister(listener); // make sure that listener is only registered once
  86         Method[] methods = getSignalHandlerMethods(listener);
  87         if (methods.length > 0) {
  88             fVIPListeners.put(listener, methods);
  89         }
  90     }
  91
  92     /**
  93      * De-register a listener object from the signal manager. This means that
  94      * its @TmfSignalHandler methods will no longer be called.
  95      *
  96      * @param listener
  97      *            The object to de-register
  98      */
  99     public static synchronized void deregister(Object listener) {
 100         fVIPListeners.remove(listener);
 101         fListeners.remove(listener);
 102     }
 103
 104     /**
 105      * Returns the list of signal handlers in the listener. Signal handler name
 106      * is irrelevant; only the annotation (@TmfSignalHandler) is important.
 107      *
 108      * @param listener
 109      * @return
 110      */
 111     private static Method[] getSignalHandlerMethods(Object listener) {
 112         List<Method> handlers = new ArrayList<>();
 113         Method[] methods = listener.getClass().getMethods();
 114         for (Method method : methods) {
 115             if (method.isAnnotationPresent(TmfSignalHandler.class)) {
 116                 handlers.add(method);
 117             }
 118         }
 119         return handlers.toArray(new Method[handlers.size()]);
 120     }
 121
 122     static int fSignalId = 0;
 123
 124     /**
 125      * Invokes the handling methods that listens to signals of a given type in
 126      * the current thread.
 127      *
 128      * The list of handlers is built on-the-fly to allow for the dynamic
 129      * creation/deletion of signal handlers. Since the number of signal handlers
 130      * shouldn't be too high, this is not a big performance issue to pay for the
 131      * flexibility.
 132      *
 133      * For synchronization purposes, the signal is bracketed by two synch
 134      * signals.
 135      *
 136      * @param signal
 137      *            the signal to dispatch
 138      */
 139     public static synchronized void dispatchSignal(TmfSignal signal) {
 140         int signalId = fSignalId++;
 141         sendSignal(new TmfStartSynchSignal(signalId));
 142         signal.setReference(signalId);
 143         sendSignal(signal);
 144         sendSignal(new TmfEndSynchSignal(signalId));
 145     }
 146
 147     /**
 148      * Invokes the handling methods that listens to signals of a given type
 149      * in a separate thread which will call
 150      * {@link TmfSignalManager#dispatchSignal(TmfSignal)}.
 151      *
 152      * If a signal is already processed the signal will be queued and
 153      * dispatched after the ongoing signal finishes.
 154      *
 155      * @param signal
 156      *            the signal to dispatch
 157      * @since 3.0
 158      */
 159     public static void dispatchSignalAsync(final TmfSignal signal) {
 160         if (!fExecutor.isShutdown()) {
 161             fExecutor.execute(new Runnable() {
 162                 @Override
 163                 public void run() {
 164                     dispatchSignal(signal);
 165                 }
 166             });
 167         }
 168     }
 169
 170     /**
 171      * Disposes the signal manager
 172      * @since 3.0
 173      */
 174     public static void dispose() {
 175         fExecutor.shutdown();
 176     }
 177
 178     private static void sendSignal(TmfSignal signal) {
 179         sendSignal(fVIPListeners, signal);
 180         sendSignal(fListeners, signal);
 181     }
 182
 183     private static void sendSignal(Map<Object, Method[]> listeners, TmfSignal signal) {
 184
 185         if (TmfCoreTracer.isSignalTraced()) {
 186             TmfCoreTracer.traceSignal(signal, "(start)"); //$NON-NLS-1$
 187         }
 188
 189         // Build the list of listener methods that are registered for this signal
 190         Class<?> signalClass = signal.getClass();
 191         Map<Object, List<Method>> targets = new HashMap<>();
 192         targets.clear();
 193         for (Map.Entry<Object, Method[]> entry : listeners.entrySet()) {
 194             List<Method> matchingMethods = new ArrayList<>();
 195             for (Method method : entry.getValue()) {
 196                 if (method.getParameterTypes()[0].isAssignableFrom(signalClass)) {
 197                     matchingMethods.add(method);
 198                 }
 199             }
 200             if (!matchingMethods.isEmpty()) {
 201                 targets.put(entry.getKey(), matchingMethods);
 202             }
 203         }
 204
 205         // Call the signal handlers
 206         for (Map.Entry<Object, List<Method>> entry : targets.entrySet()) {
 207             for (Method method : entry.getValue()) {
 208                 try {
 209                     method.invoke(entry.getKey(), new Object[] { signal });
 210                     if (TmfCoreTracer.isSignalTraced()) {
 211                         Object key = entry.getKey();
 212                         String hash = String.format("%1$08X", entry.getKey().hashCode()); //$NON-NLS-1$
 213                         String target = "[" + hash + "] " + key.getClass().getSimpleName() + ":" + method.getName();   //$NON-NLS-1$//$NON-NLS-2$//$NON-NLS-3$
 214                         TmfCoreTracer.traceSignal(signal, target);
 215                     }
 216                 } catch (IllegalArgumentException e) {
 217                     Activator.logError("Exception handling signal " + signal + " in method " + method, e); //$NON-NLS-1$ //$NON-NLS-2$
 218                 } catch (IllegalAccessException e) {
 219                     Activator.logError("Exception handling signal " + signal + " in method " + method, e); //$NON-NLS-1$ //$NON-NLS-2$
 220                 } catch (InvocationTargetException e) {
 221                     Activator.logError("Exception handling signal " + signal + " in method " + method, e); //$NON-NLS-1$ //$NON-NLS-2$
 222                 }
 223             }
 224         }
 225
 226         if (TmfCoreTracer.isSignalTraced()) {
 227             TmfCoreTracer.traceSignal(signal, "(end)"); //$NON-NLS-1$
 228         }
 229     }
 230
 231 }