bundles/org.simantics.browsing.ui.common/src/org/simantics/browsing/ui/common/extension/internal/ContributorExtensionManager.java

   1 /*******************************************************************************
   2  * Copyright (c) 2007, 2010 Association for Decentralized Information Management
   3  * in Industry THTH ry.
   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  * Contributors:
  10  *     VTT Technical Research Centre of Finland - initial API and implementation
  11  *******************************************************************************/
  12 package org.simantics.browsing.ui.common.extension.internal;
  13
  14 import java.util.Arrays;
  15 import java.util.HashSet;
  16 import java.util.Set;
  17
  18 import org.eclipse.core.runtime.CoreException;
  19 import org.eclipse.core.runtime.IConfigurationElement;
  20 import org.eclipse.core.runtime.IExtension;
  21 import org.eclipse.core.runtime.IExtensionPoint;
  22 import org.eclipse.core.runtime.Platform;
  23 import org.eclipse.core.runtime.dynamichelpers.ExtensionTracker;
  24 import org.eclipse.core.runtime.dynamichelpers.IExtensionChangeHandler;
  25 import org.eclipse.core.runtime.dynamichelpers.IExtensionTracker;
  26 import org.eclipse.core.runtime.dynamichelpers.IFilter;
  27 import org.simantics.browsing.ui.common.Activator;
  28 import org.simantics.browsing.ui.common.ErrorLogger;
  29 import org.simantics.browsing.ui.content.Contributor;
  30 import org.simantics.utils.strings.StringUtils;
  31
  32 /**
  33  * @author Tuukka Lehtonen
  34  */
  35 public abstract class ContributorExtensionManager<Factory> implements IExtensionChangeHandler {
  36
  37     private final static String                NAMESPACE    = Activator.PLUGIN_ID;
  38
  39     private ExtensionTracker                   tracker;
  40
  41     @SuppressWarnings("unchecked")
  42     ContributorExtension<Factory>[]            extensions   = new ContributorExtension[0];
  43
  44     abstract public String getExtensionPointName();
  45
  46     ContributorExtensionManager() {
  47         tracker = new ExtensionTracker();
  48
  49         // Cache defined actions
  50         IExtensionPoint expt = Platform.getExtensionRegistry().getExtensionPoint(NAMESPACE, getExtensionPointName());
  51         loadExtensions(expt.getConfigurationElements());
  52
  53         // Start tracking for new and removed extensions
  54         IFilter filter = ExtensionTracker.createExtensionPointFilter(expt);
  55         tracker.registerHandler(this, filter);
  56     }
  57
  58     @SuppressWarnings("unchecked")
  59     void close() {
  60         tracker.close();
  61         tracker = null;
  62         extensions = new ContributorExtension[0];
  63     }
  64
  65     public ContributorExtension<Factory>[] getExtensions() {
  66         return extensions;
  67     }
  68
  69     @SuppressWarnings("unchecked")
  70     private void loadExtensions(IConfigurationElement[] elements) {
  71
  72         Set<ContributorExtension<Factory>> newExtensions = new HashSet<ContributorExtension<Factory>>(Arrays.asList(extensions));
  73
  74         for (IConfigurationElement el : elements) {
  75             try {
  76
  77                 String id = StringUtils.safeString(el.getAttribute("id"));
  78                 Contributor<Factory> factory = (Contributor<Factory>)el.createExecutableExtension("class");
  79                 ContributorExtension<Factory> ext = new ContributorExtensionImpl<Factory>(id, factory);
  80
  81                 // Start tracking the new extension object, its removal will be notified of
  82                 // with removeExtension(extension, Object[]).
  83                 tracker.registerObject(el.getDeclaringExtension(), ext, IExtensionTracker.REF_STRONG);
  84
  85                 newExtensions.add(ext);
  86             } catch (CoreException e) {
  87                 ErrorLogger.defaultLogError("Failed to initialize " + getExtensionPointName() + " extension \"" + el.getName()
  88                         + "\" with name \"" + el.getAttribute("name") + "\": "
  89                         + e.getMessage(), e);
  90             }
  91         }
  92
  93         // Atomic assignment
  94         this.extensions = newExtensions.toArray(new ContributorExtension[newExtensions.size()]);
  95     }
  96
  97     @Override
  98     public void addExtension(IExtensionTracker tracker, IExtension extension) {
  99         loadExtensions(extension.getConfigurationElements());
 100     }
 101
 102     @SuppressWarnings("unchecked")
 103     @Override
 104     public void removeExtension(IExtension extension, Object[] objects) {
 105         Set<ContributorExtension<Factory>> newExtensions = new HashSet<ContributorExtension<Factory>>(Arrays.asList(extensions));
 106
 107         for (Object o : objects) {
 108             tracker.unregisterObject(extension, o);
 109             newExtensions.remove(o);
 110         }
 111
 112         // Atomic assignment
 113         this.extensions = newExtensions.toArray(new ContributorExtension[newExtensions.size()]);
 114     }
 115
 116 }