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/*******************************************************************************
* Copyright (c) 2000, 2003 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Common Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/cpl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.core.internal.filebuffers;
import java.text.MessageFormat;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.StringTokenizer;
import org.eclipse.core.filebuffers.IDocumentFactory;
import org.eclipse.core.filebuffers.IDocumentSetupParticipant;
import org.eclipse.core.resources.IFile;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IExtensionPoint;
import org.eclipse.core.runtime.ILog;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Platform;
import org.eclipse.core.runtime.Status;
/**
* This registry manages shareable document factories. Document factories are specified
* in <code>plugin.xml</code> per file name extension.
*/
public class ExtensionsRegistry {
private final static String WILDCARD= "*"; //$NON-NLS-1$
/** The mapping between name extensions and configuration elements describing document factories. */
private Map fFactoryDescriptors= new HashMap();
/** The mapping between configuration elements for document factories and instantiated document factories. */
private Map fFactories= new HashMap();
/** The mapping between name extensions and configuration elements describing document setup participants. */
private Map fSetupParticipantDescriptors= new HashMap();
/** The mapping between configuration elements for setup participants and instantiated setup participants. */
private Map fSetupParticipants= new HashMap();
/**
* Creates a new document factory registry and intializes it with the information
* found in the plugin registry.
*/
public ExtensionsRegistry() {
initialize("documentCreation", "extensions", fFactoryDescriptors); //$NON-NLS-1$ //$NON-NLS-2$
initialize("documentSetup", "extensions", fSetupParticipantDescriptors);
}
/**
* Reads the comma-separated value of the given configuration element
* for the given attribute name and remembers the configuration element
* in the given map under the individual tokens of the attribute value.
*/
private void read(String attributeName, IConfigurationElement element, Map map) {
String value= element.getAttribute(attributeName);
if (value != null) {
StringTokenizer tokenizer= new StringTokenizer(value, ","); //$NON-NLS-1$
while (tokenizer.hasMoreTokens()) {
String token= tokenizer.nextToken().trim();
Set s= (Set) map.get(token);
if (s == null) {
s= new HashSet();
map.put(token, s);
}
s.add(element);
}
}
}
/**
* Adds an entry to the log of this plugin for the given status
* @param status the status to log
*/
private void log(IStatus status) {
ILog log= Platform.getPlugin(FileBuffersPlugin.PLUGIN_ID).getLog();
log.log(status);
}
/**
* Initializes this registry. It retrieves all implementers of the given
* extension point and remembers those implementers based on the
* file name extensions in the given map.
*
* @param extensionPointName the name of the extension point
* @param childElementName the name of the child elements
* @param descriptors the map to be filled
*/
private void initialize(String extensionPointName, String childElementName, Map descriptors) {
IExtensionPoint extensionPoint= Platform.getPluginRegistry().getExtensionPoint(FileBuffersPlugin.PLUGIN_ID, extensionPointName);
if (extensionPoint == null) {
log(new Status(IStatus.ERROR, FileBuffersPlugin.PLUGIN_ID, 0, MessageFormat.format("Extension point \"{0}\" not found.", new Object[] { extensionPointName}), null));
return;
}
IConfigurationElement[] elements= extensionPoint.getConfigurationElements();
for (int i= 0; i < elements.length; i++)
read(childElementName, elements[i], descriptors);
}
/**
* Returns the executable extension for the given configuration element.
* If there is no instantiated extension remembered for this
* element, a new extension is created and put into the cache if it is of the requested type.
*
* @param entry the configuration element
* @param extensions the map of instantiated extensions
* @param extensionType the requested result type
*/
private Object getExtension(IConfigurationElement entry, Map extensions, Class extensionType) {
Object extension= extensions.get(entry);
if (extension != null)
return extension;
try {
extension= entry.createExecutableExtension("class"); //$NON-NLS-1$
} catch (CoreException x) {
log(x.getStatus());
}
if (extensionType.isInstance(extension)) {
extensions.put(entry, extension);
return extension;
}
return null;
}
/**
* Returns the first enumerated element of the given set.
*
* @param set the set from which to choose
*/
private IConfigurationElement selectConfigurationElement(Set set) {
if (set != null && !set.isEmpty()) {
Iterator e= set.iterator();
return (IConfigurationElement) e.next();
}
return null;
}
/**
* Returns a shareable document factory for the given file name extension.
*
* @param extension the name extension to be used for lookup
* @return the shareable document factory or <code>null</code>
*/
private IDocumentFactory getDocumentFactory(String extension) {
Set set= (Set) fFactoryDescriptors.get(extension);
if (set != null) {
IConfigurationElement entry= selectConfigurationElement(set);
return (IDocumentFactory) getExtension(entry, fFactories, IDocumentFactory.class);
}
return null;
}
/**
* Returns the set of setup participants for the given file name.
*
* @param extension the name extension to be used for lookup
* @return the shareable set of document setup participants
*/
private List getDocumentSetupParticipants(String extension) {
Set set= (Set) fSetupParticipantDescriptors.get(extension);
if (set == null)
return null;
List participants= new ArrayList();
Iterator e= set.iterator();
while (e.hasNext()) {
IConfigurationElement entry= (IConfigurationElement) e.next();
Object participant= getExtension(entry, fSetupParticipants, IDocumentSetupParticipant.class);
if (participant != null)
participants.add(participant);
}
return participants;
}
/**
* Returns the shareable document factory for the given file.
*
* @param file the file for whose type the factory is looked up
* @return the shareable document factory
*/
public IDocumentFactory getDocumentFactory(IFile file) {
IDocumentFactory factory= getDocumentFactory(file.getFileExtension());
if (factory == null)
factory= getDocumentFactory(WILDCARD);
return factory;
}
/**
* Returns the shareable set of document setup participants for the given file.
*
* @param file the file for which to look up the setup participants
* @return the shareable set of document setup participants
*/
public IDocumentSetupParticipant[] getDocumentSetupParticipants(IFile file) {
List participants= new ArrayList();
List p= getDocumentSetupParticipants(file.getFileExtension());
if (p != null)
participants.addAll(p);
p= getDocumentSetupParticipants(WILDCARD);
if (p != null)
participants.addAll(p);
IDocumentSetupParticipant[] result= new IDocumentSetupParticipant[participants.size()];
participants.toArray(result);
return result;
}
}
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