/*******************************************************************************
* Copyright (c) 2006, 2007 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.ui;
import java.util.ArrayList;
import java.util.List;
import java.util.StringTokenizer;
import org.eclipse.core.runtime.IAdaptable;
import org.eclipse.core.runtime.IAdapterManager;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IExecutableExtension;
import org.eclipse.core.runtime.Platform;
import org.eclipse.ui.internal.WorkbenchPlugin;
import org.osgi.framework.Bundle;
import org.osgi.service.packageadmin.ExportedPackage;
import org.osgi.service.packageadmin.PackageAdmin;
import org.osgi.util.tracker.ServiceTracker;
/**
* Basic IWorkingSetElementAdapter implementation that allows plugins to decribe
* simple declarative element adapters.
* <p>
* The executable extension format for this class is as follows:<br/>
* <code><workingSet
* elementAdapterClass="org.eclipse.ui.BasicWorkingSetElementAdapter:class1.to.adapt.to[;option1=value1][;option2=value2],class2.to.adapt.to[;option1=value1][;option2=value2],...">
* ... </workingSet></code>
* </p>
* <p>
* The valid options are:<br/>
* <dl>
* <dt>adapt</dt>
* <dd>Values: <code>true</code> or <code>true</code>. Specifies whether
* or not the platform {@link org.eclipse.core.runtime.IAdapterManager} and the
* {@link org.eclipse.core.runtime.IAdaptable} interface should be consulted.</dd>
* </dl>
* </p>
*
* Please see the {@link #adaptElements(IWorkingSet, IAdaptable[])} method for
* details on behavior of this implementation.
*
* @since 3.3
*/
public final class BasicWorkingSetElementAdapter implements
IWorkingSetElementAdapter, IExecutableExtension {
private class Type {
private static final int NONE = 0;
private static final int ADAPT = 1;
String className;
int flags;
}
private Type[] preferredTypes = new Type[0];
private ServiceTracker packageTracker;
/**
* When invoked this method will iterate over all classes specified as
* IExecutableExtension arguements to this class in order and compare with
* the elements. If the element is directly assignable to the provided class
* then it is added to the result array as is. If the class has specified
* "adapt=true" as an argument and there is an available adapter in the
* platform IAdapterManager then it is returned. Finally, if "adapt=true"
* and the class is already loaded (determined by inspecting exported
* bundles via the platform PackageAdmin) a direct query for the adapter is
* made on the object and if it is not <code>null</code> then it is
* returned.
* <p>
* A consequence of the above is that it is possible for this method to
* return differing results based on the state of bundles loaded within the
* system.
* </p>
*
* @see org.eclipse.ui.IWorkingSetElementAdapter#adaptElements(org.eclipse.ui.IWorkingSet,
* org.eclipse.core.runtime.IAdaptable[])
* @see org.eclipse.core.runtime.IAdapterManager#getAdapter(Object, String)
* @see org.osgi.service.packageadmin.PackageAdmin#getExportedPackage(String)
*/
public IAdaptable[] adaptElements(IWorkingSet ws, IAdaptable[] elements) {
List adaptedElements = new ArrayList();
for (int i = 0; i < elements.length; i++) {
IAdaptable adaptable = adapt(elements[i]);
if (adaptable != null)
adaptedElements.add(adaptable);
}
return (IAdaptable[]) adaptedElements
.toArray(new IAdaptable[adaptedElements.size()]);
}
/**
* Adapt the given adaptable. Compares the given adaptable against the list
* of desired types and returns the first type that generates a match.
*
* @param adaptable
* the adaptable to adapt
* @return the resultant adaptable. May be the same adaptable, a new
* adaptable, or <code>null</code>.
*/
private IAdaptable adapt(IAdaptable adaptable) {
for (int i = 0; i < preferredTypes.length; i++) {
IAdaptable adaptedAdaptable = adapt(preferredTypes[i], adaptable);
if (adaptedAdaptable != null)
return adaptedAdaptable;
}
return null;
}
/**
* Adapt the given adaptable given the reference type.
*
* @param type
* the reference type
* @param adaptable
* the adaptable to adapt
* @return the resultant adaptable. May be the same adaptable, a new
* adaptable, or <code>null</code>.
*/
private IAdaptable adapt(Type type, IAdaptable adaptable) {
IAdapterManager adapterManager = Platform.getAdapterManager();
Class[] directClasses = adapterManager.computeClassOrder(adaptable
.getClass());
for (int i = 0; i < directClasses.length; i++) {
Class clazz = directClasses[i];
if (clazz.getName().equals(type.className))
return adaptable;
}
if ((type.flags & Type.ADAPT) != 0) {
Object adapted = adapterManager.getAdapter(adaptable,
type.className);
if (adapted instanceof IAdaptable)
return (IAdaptable) adapted;
PackageAdmin admin = getPackageAdmin();
if (admin != null) {
int lastDot = type.className.lastIndexOf('.');
if (lastDot > 0) { // this lives in a package
String packageName = type.className.substring(0, lastDot);
ExportedPackage[] packages = admin
.getExportedPackages(packageName);
if (packages != null && packages.length == 1) {
// if there is exactly one exporter of this
// package
// we can go further
if (packages[0].getExportingBundle().getState() == Bundle.ACTIVE) {
try {
// if the bundle is loaded we can safely get the
// class object and check for an adapter on the
// object directly
adapted = adaptable.getAdapter(packages[0]
.getExportingBundle().loadClass(
type.className));
if (adapted instanceof IAdaptable)
return (IAdaptable) adapted;
} catch (ClassNotFoundException e) {
WorkbenchPlugin.log(e);
}
}
}
}
}
}
return null;
}
/*
* (non-Javadoc)
*
* @see org.eclipse.ui.IWorkingSetElementAdapter#dispose()
*/
public void dispose() {
if (packageTracker != null)
packageTracker.close();
}
/*
* (non-Javadoc)
*
* @see org.eclipse.core.runtime.IExecutableExtension#setInitializationData(org.eclipse.core.runtime.IConfigurationElement,
* java.lang.String, java.lang.Object)
*/
public void setInitializationData(IConfigurationElement config,
String propertyName, Object data) {
if (data instanceof String) {
List preferredTypes = new ArrayList(0);
for (StringTokenizer toker = new StringTokenizer((String) data, ","); toker.hasMoreTokens();) {//$NON-NLS-1$
String classNameAndOptions = toker.nextToken();
Type record = new Type();
parseOptions(classNameAndOptions, record);
preferredTypes.add(record);
}
this.preferredTypes = (Type[]) preferredTypes
.toArray(new Type[preferredTypes.size()]);
}
}
/**
* Parse classname/option strings in the form:<br/>
* <code>some.package.Class[:option1=value1][:option2=value2]...
*
* @param classNameAndOptions the class name and possibly options to parse
* @param record the record to fill
*/
private void parseOptions(String classNameAndOptions, Type record) {
for (StringTokenizer toker = new StringTokenizer(classNameAndOptions,
";"); toker.hasMoreTokens();) { //$NON-NLS-1$
String token = toker.nextToken();
if (record.className == null)
record.className = token;
else {
for (StringTokenizer pair = new StringTokenizer(token, "="); pair.hasMoreTokens();) {//$NON-NLS-1$
if (pair.countTokens() == 2) {
String param = pair.nextToken();
String value = pair.nextToken();
if ("adapt".equals(param)) { //$NON-NLS-1$
record.flags ^= "true".equals(value) ? Type.ADAPT : Type.NONE; //$NON-NLS-1$
}
}
}
}
}
}
/**
* Prime the PackageAdmin service tracker and return the service (if
* available).
*
* @return the PackageAdmin service or null if it is not available
*/
private PackageAdmin getPackageAdmin() {
if (packageTracker == null) {
packageTracker = new ServiceTracker(WorkbenchPlugin.getDefault()
.getBundleContext(), PackageAdmin.class.getName(), null);
packageTracker.open();
}
return (PackageAdmin) packageTracker.getService();
}
}