tmf/org.eclipse.tracecompass.tmf.core/src/org/eclipse/tracecompass/tmf/core/symbols/SymbolProviderManager.java

   1 /*******************************************************************************
   2  * Copyright (c) 2016-2017 Movidius Inc. and others
   3  *
   4  * All rights reserved. This program and the accompanying materials
   5  * are made available under the terms of the Eclipse Public License v1.0
   6  * which accompanies this distribution, and is available at
   7  * http://www.eclipse.org/legal/epl-v10.html
   8  *******************************************************************************/
   9
  10 package org.eclipse.tracecompass.tmf.core.symbols;
  11
  12 import static org.eclipse.tracecompass.common.core.NonNullUtils.checkNotNull;
  13
  14 import java.lang.ref.WeakReference;
  15 import java.util.ArrayList;
  16 import java.util.Comparator;
  17 import java.util.List;
  18 import java.util.Map;
  19 import java.util.WeakHashMap;
  20
  21 import org.eclipse.core.runtime.CoreException;
  22 import org.eclipse.core.runtime.IConfigurationElement;
  23 import org.eclipse.core.runtime.Platform;
  24 import org.eclipse.jdt.annotation.Nullable;
  25 import org.eclipse.tracecompass.internal.tmf.core.Activator;
  26 import org.eclipse.tracecompass.tmf.core.trace.ITmfTrace;
  27
  28 /**
  29  * This class offer services around the
  30  * <code>org.eclipse.tracecompass.tmf.core.symbolProvider</code> extension
  31  * point.
  32  *
  33  * @author Robert Kiss
  34  * @since 2.4
  35  */
  36 public final class SymbolProviderManager {
  37
  38     /**
  39      * The singleton instance of this manager
  40      */
  41     private static @Nullable SymbolProviderManager INSTANCE;
  42
  43     private static final String OLD_EXTENSION_POINT_ID = "org.eclipse.tracecompass.tmf.ui.symbolProvider"; //$NON-NLS-1$
  44     private static final String EXTENSION_POINT_ID = "org.eclipse.tracecompass.tmf.core.symbolProvider"; //$NON-NLS-1$
  45     private static final String ELEM_NAME_PROVIDER = "providerFactory"; //$NON-NLS-1$
  46     private static final String ATTR_CLASS = "class"; //$NON-NLS-1$
  47     private static final String ATTR_PRIORITY = "priority"; //$NON-NLS-1$
  48
  49     private final List<SymbolProviderFactoryWrapper> fProviders;
  50
  51     private final Map<ITmfTrace, WeakReference<ISymbolProvider>> fInstances = new WeakHashMap<>();
  52
  53     /**
  54      * Internal class used to store extension point information
  55      *
  56      */
  57     private static class SymbolProviderFactoryWrapper {
  58
  59         public final ISymbolProviderFactory factory;
  60         public final int priority;
  61
  62         private SymbolProviderFactoryWrapper(ISymbolProviderFactory factory, int priority) {
  63             this.factory = factory;
  64             this.priority = priority;
  65         }
  66     }
  67
  68     /**
  69      *
  70      * @return the singleton instance of this class
  71      */
  72     public static synchronized SymbolProviderManager getInstance() {
  73         SymbolProviderManager manager = INSTANCE;
  74         if (manager == null) {
  75             manager = new SymbolProviderManager();
  76             INSTANCE = manager;
  77         }
  78         return manager;
  79     }
  80
  81     /**
  82      * The private constructor of this manager
  83      */
  84     private SymbolProviderManager() {
  85         fProviders = new ArrayList<>();
  86         load(OLD_EXTENSION_POINT_ID);
  87         load(EXTENSION_POINT_ID);
  88         // Those with a higher priority need to be on top
  89         fProviders.sort(Comparator.comparingLong(o -> -o.priority));
  90     }
  91
  92     private void load(String configElemPath) {
  93         IConfigurationElement[] configElements = Platform.getExtensionRegistry().getConfigurationElementsFor(configElemPath);
  94         for (IConfigurationElement element : configElements) {
  95             if (element != null && ELEM_NAME_PROVIDER.equals(element.getName())) {
  96                 try {
  97                     Object extension = checkNotNull(element.createExecutableExtension(ATTR_CLASS));
  98                     int priority = 0;
  99                     try {
 100                         priority = Integer.parseInt(element.getAttribute(ATTR_PRIORITY));
 101                     } catch (NumberFormatException e) {
 102                         // safe to ignore
 103                     }
 104                     fProviders.add(new SymbolProviderFactoryWrapper((ISymbolProviderFactory) extension, priority));
 105                 } catch (CoreException | ClassCastException e) {
 106                     Activator.logError("Exception while loading extensions", e); //$NON-NLS-1$
 107                 }
 108             }
 109         }
 110     }
 111
 112     /**
 113      * Locate an {@link ISymbolProvider} capable to resolve symbols from the
 114      * given trace. If no such provider is defined an instance of
 115      * {@link DefaultSymbolProvider} will be returned
 116      *
 117      * @param trace
 118      *            The trace to create a provider for
 119      * @return a valid {@link ISymbolProvider}, never null
 120      */
 121     public ISymbolProvider getSymbolProvider(ITmfTrace trace) {
 122         // Check to see if we already have a provider for this trace
 123         synchronized (fInstances) {
 124             WeakReference<ISymbolProvider> reference = fInstances.get(trace);
 125             if (reference != null) {
 126                 ISymbolProvider provider = reference.get();
 127                 if (provider != null) {
 128                     return provider;
 129                 }
 130             }
 131             // we don't have yet an instance, build one
 132             for (SymbolProviderFactoryWrapper wrapper : fProviders) {
 133                 ISymbolProviderFactory factory = wrapper.factory;
 134                 ISymbolProvider provider = factory.createProvider(trace);
 135                 if (provider != null) {
 136                     fInstances.put(trace, new WeakReference<>(provider));
 137                     return provider;
 138                 }
 139             }
 140         }
 141         // No provider found, return the default one
 142         return new DefaultSymbolProvider(trace);
 143     }
 144
 145 }