net.sourceforge.phpeclipse/src/net/sourceforge/phpdt/internal/ui/text/folding/JavaFoldingStructureProviderRegistry.java

   1 /*******************************************************************************
   2  * Copyright (c) 2000, 2003 IBM Corporation and others.
   3  * All rights reserved. This program and the accompanying materials
   4  * are made available under the terms of the Common Public License v1.0
   5  * which accompanies this distribution, and is available at
   6  * http://www.eclipse.org/legal/cpl-v10.html
   7  *
   8  * Contributors:
   9  *     IBM Corporation - initial API and implementation
  10  *******************************************************************************/
  11 package net.sourceforge.phpdt.internal.ui.text.folding;
  12
  13 import java.util.Collections;
  14 import java.util.HashMap;
  15 import java.util.Map;
  16
  17 import net.sourceforge.phpdt.ui.PreferenceConstants;
  18 import net.sourceforge.phpdt.ui.text.folding.IJavaFoldingStructureProvider;
  19 import net.sourceforge.phpeclipse.PHPeclipsePlugin;
  20
  21 import org.eclipse.core.runtime.CoreException;
  22 import org.eclipse.core.runtime.IConfigurationElement;
  23 import org.eclipse.core.runtime.IExtensionRegistry;
  24 import org.eclipse.core.runtime.Platform;
  25
  26 /**
  27  * @since 3.0
  28  */
  29 public class JavaFoldingStructureProviderRegistry {
  30
  31         private static final String EXTENSION_POINT = "foldingStructureProviders"; //$NON-NLS-1$
  32
  33         /** The map of descriptors, indexed by their identifiers. */
  34         private Map fDescriptors;
  35
  36         /**
  37          * Creates a new instance.
  38          */
  39         public JavaFoldingStructureProviderRegistry() {
  40         }
  41
  42         /**
  43          * Returns an array of <code>IJavaFoldingProviderDescriptor</code>
  44          * describing all extension to the <code>foldingProviders</code> extension
  45          * point.
  46          *
  47          * @return the list of extensions to the
  48          *         <code>quickDiffReferenceProvider</code> extension point.
  49          */
  50         public JavaFoldingStructureProviderDescriptor[] getFoldingProviderDescriptors() {
  51                 synchronized (this) {
  52                         ensureRegistered();
  53                         return (JavaFoldingStructureProviderDescriptor[]) fDescriptors
  54                                         .values()
  55                                         .toArray(
  56                                                         new JavaFoldingStructureProviderDescriptor[fDescriptors
  57                                                                         .size()]);
  58                 }
  59         }
  60
  61         /**
  62          * Returns the folding provider with identifier <code>id</code> or
  63          * <code>null</code> if no such provider is registered.
  64          *
  65          * @param id
  66          *            the identifier for which a provider is wanted
  67          * @return the corresponding provider, or <code>null</code> if none can be
  68          *         found
  69          */
  70         public JavaFoldingStructureProviderDescriptor getFoldingProviderDescriptor(
  71                         String id) {
  72                 synchronized (this) {
  73                         ensureRegistered();
  74                         return (JavaFoldingStructureProviderDescriptor) fDescriptors
  75                                         .get(id);
  76                 }
  77         }
  78
  79         /**
  80          * Instantiates and returns the provider that is currently configured in the
  81          * preferences.
  82          *
  83          * @return the current provider according to the preferences
  84          */
  85         public IJavaFoldingStructureProvider getCurrentFoldingProvider() {
  86                 String id = PHPeclipsePlugin.getDefault().getPreferenceStore()
  87                                 .getString(PreferenceConstants.EDITOR_FOLDING_PROVIDER);
  88                 JavaFoldingStructureProviderDescriptor desc = getFoldingProviderDescriptor(id);
  89                 if (desc != null) {
  90                         try {
  91                                 return desc.createProvider();
  92                         } catch (CoreException e) {
  93                                 PHPeclipsePlugin.log(e);
  94                         }
  95                 }
  96                 return null;
  97         }
  98
  99         /**
 100          * Ensures that the extensions are read and stored in
 101          * <code>fDescriptors</code>.
 102          */
 103         private void ensureRegistered() {
 104                 if (fDescriptors == null)
 105                         reloadExtensions();
 106         }
 107
 108         /**
 109          * Reads all extensions.
 110          * <p>
 111          * This method can be called more than once in order to reload from a
 112          * changed extension registry.
 113          * </p>
 114          */
 115         public void reloadExtensions() {
 116                 IExtensionRegistry registry = Platform.getExtensionRegistry();
 117                 Map map = new HashMap();
 118
 119                 IConfigurationElement[] elements = registry
 120                                 .getConfigurationElementsFor(PHPeclipsePlugin.getPluginId(),
 121                                                 EXTENSION_POINT);
 122                 for (int i = 0; i < elements.length; i++) {
 123                         JavaFoldingStructureProviderDescriptor desc = new JavaFoldingStructureProviderDescriptor(
 124                                         elements[i]);
 125                         map.put(desc.getId(), desc);
 126                 }
 127
 128                 synchronized (this) {
 129                         fDescriptors = Collections.unmodifiableMap(map);
 130                 }
 131         }
 132
 133 }