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

   1 /*******************************************************************************\r
   2  * Copyright (c) 2007, 2010 Association for Decentralized Information Management\r
   3  * in Industry THTH ry.\r
   4  * All rights reserved. This program and the accompanying materials\r
   5  * are made available under the terms of the Eclipse Public License v1.0\r
   6  * which accompanies this distribution, and is available at\r
   7  * http://www.eclipse.org/legal/epl-v10.html\r
   8  *\r
   9  * Contributors:\r
  10  *     VTT Technical Research Centre of Finland - initial API and implementation\r
  11  *******************************************************************************/\r
  12 package org.simantics.browsing.ui.common.extension.internal;\r
  13 \r
  14 import java.util.Arrays;\r
  15 import java.util.HashSet;\r
  16 import java.util.Set;\r
  17 \r
  18 import org.eclipse.core.runtime.CoreException;\r
  19 import org.eclipse.core.runtime.IConfigurationElement;\r
  20 import org.eclipse.core.runtime.IExtension;\r
  21 import org.eclipse.core.runtime.IExtensionPoint;\r
  22 import org.eclipse.core.runtime.Platform;\r
  23 import org.eclipse.core.runtime.dynamichelpers.ExtensionTracker;\r
  24 import org.eclipse.core.runtime.dynamichelpers.IExtensionChangeHandler;\r
  25 import org.eclipse.core.runtime.dynamichelpers.IExtensionTracker;\r
  26 import org.eclipse.core.runtime.dynamichelpers.IFilter;\r
  27 import org.simantics.browsing.ui.common.Activator;\r
  28 import org.simantics.browsing.ui.common.ErrorLogger;\r
  29 import org.simantics.browsing.ui.content.Contributor;\r
  30 import org.simantics.utils.strings.StringUtils;\r
  31 \r
  32 /**\r
  33  * @author Tuukka Lehtonen\r
  34  */\r
  35 public abstract class ContributorExtensionManager<Factory> implements IExtensionChangeHandler {\r
  36 \r
  37     private final static String                NAMESPACE    = Activator.PLUGIN_ID;\r
  38 \r
  39     private ExtensionTracker                   tracker;\r
  40 \r
  41     @SuppressWarnings("unchecked")\r
  42     ContributorExtension<Factory>[]            extensions   = new ContributorExtension[0];\r
  43 \r
  44     abstract public String getExtensionPointName();\r
  45 \r
  46     ContributorExtensionManager() {\r
  47         tracker = new ExtensionTracker();\r
  48 \r
  49         // Cache defined actions\r
  50         IExtensionPoint expt = Platform.getExtensionRegistry().getExtensionPoint(NAMESPACE, getExtensionPointName());\r
  51         loadExtensions(expt.getConfigurationElements());\r
  52 \r
  53         // Start tracking for new and removed extensions\r
  54         IFilter filter = ExtensionTracker.createExtensionPointFilter(expt);\r
  55         tracker.registerHandler(this, filter);\r
  56     }\r
  57 \r
  58     @SuppressWarnings("unchecked")\r
  59     void close() {\r
  60         tracker.close();\r
  61         tracker = null;\r
  62         extensions = new ContributorExtension[0];\r
  63     }\r
  64 \r
  65     public ContributorExtension<Factory>[] getExtensions() {\r
  66         return extensions;\r
  67     }\r
  68 \r
  69     @SuppressWarnings("unchecked")\r
  70     private void loadExtensions(IConfigurationElement[] elements) {\r
  71 \r
  72         Set<ContributorExtension<Factory>> newExtensions = new HashSet<ContributorExtension<Factory>>(Arrays.asList(extensions));\r
  73 \r
  74         for (IConfigurationElement el : elements) {\r
  75             try {\r
  76 \r
  77                 String id = StringUtils.safeString(el.getAttribute("id"));\r
  78                 Contributor<Factory> factory = (Contributor<Factory>)el.createExecutableExtension("class");\r
  79                 ContributorExtension<Factory> ext = new ContributorExtensionImpl<Factory>(id, factory);\r
  80 \r
  81                 // Start tracking the new extension object, its removal will be notified of\r
  82                 // with removeExtension(extension, Object[]).\r
  83                 tracker.registerObject(el.getDeclaringExtension(), ext, IExtensionTracker.REF_STRONG);\r
  84 \r
  85                 newExtensions.add(ext);\r
  86             } catch (CoreException e) {\r
  87                 ErrorLogger.defaultLogError("Failed to initialize " + getExtensionPointName() + " extension \"" + el.getName()\r
  88                         + "\" with name \"" + el.getAttribute("name") + "\": "\r
  89                         + e.getMessage(), e);\r
  90             }\r
  91         }\r
  92 \r
  93         // Atomic assignment\r
  94         this.extensions = newExtensions.toArray(new ContributorExtension[newExtensions.size()]);\r
  95     }\r
  96 \r
  97     @Override\r
  98     public void addExtension(IExtensionTracker tracker, IExtension extension) {\r
  99         loadExtensions(extension.getConfigurationElements());\r
 100     }\r
 101 \r
 102     @SuppressWarnings("unchecked")\r
 103     @Override\r
 104     public void removeExtension(IExtension extension, Object[] objects) {\r
 105         Set<ContributorExtension<Factory>> newExtensions = new HashSet<ContributorExtension<Factory>>(Arrays.asList(extensions));\r
 106 \r
 107         for (Object o : objects) {\r
 108             tracker.unregisterObject(extension, o);\r
 109             newExtensions.remove(o);\r
 110         }\r
 111 \r
 112         // Atomic assignment\r
 113         this.extensions = newExtensions.toArray(new ContributorExtension[newExtensions.size()]);\r
 114     }\r
 115 \r
 116 }\r