/*******************************************************************************
* Copyright (c) 2005, 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.internal.browser;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IExtension;
import org.eclipse.core.runtime.IExtensionPoint;
import org.eclipse.core.runtime.Platform;
import org.eclipse.core.runtime.dynamichelpers.ExtensionTracker;
import org.eclipse.core.runtime.dynamichelpers.IExtensionChangeHandler;
import org.eclipse.core.runtime.dynamichelpers.IExtensionTracker;
import org.eclipse.swt.custom.BusyIndicator;
import org.eclipse.swt.widgets.Display;
import org.eclipse.ui.PartInitException;
import org.eclipse.ui.PlatformUI;
import org.eclipse.ui.browser.AbstractWorkbenchBrowserSupport;
import org.eclipse.ui.browser.IWebBrowser;
import org.eclipse.ui.browser.IWorkbenchBrowserSupport;
import org.eclipse.ui.internal.WorkbenchPlugin;
import org.eclipse.ui.internal.registry.IWorkbenchRegistryConstants;
/**
* Implements the support interface and delegates the calls to the active
* support if contributed via the extension point, or the default support
* otherwise.
*
* @since 3.1
*/
public class WorkbenchBrowserSupport extends AbstractWorkbenchBrowserSupport {
private static WorkbenchBrowserSupport instance;
private IWorkbenchBrowserSupport activeSupport;
private boolean initialized;
private String desiredBrowserSupportId;
private IExtensionChangeHandler handler = new IExtensionChangeHandler() {
/* (non-Javadoc)
* @see org.eclipse.core.runtime.dynamicHelpers.IExtensionChangeHandler#addExtension(org.eclipse.core.runtime.dynamicHelpers.IExtensionTracker, org.eclipse.core.runtime.IExtension)
*/
public void addExtension(IExtensionTracker tracker,IExtension extension) {
//Do nothing
}
/* (non-Javadoc)
* @see org.eclipse.core.runtime.dynamicHelpers.IExtensionChangeHandler#removeExtension(org.eclipse.core.runtime.IExtension, java.lang.Object[])
*/
public void removeExtension(IExtension source, Object[] objects) {
for (int i = 0; i < objects.length; i++) {
if (objects[i] == activeSupport) {
dispose();
// remove ourselves - we'll be added again in initalize if
// needed
PlatformUI.getWorkbench().getExtensionTracker()
.unregisterHandler(handler);
}
}
}
};
/**
* Cannot be instantiated from outside.
*/
private WorkbenchBrowserSupport() {
}
/**
* Returns the shared instance.
*
* @return shared instance
*/
public static IWorkbenchBrowserSupport getInstance() {
if (instance == null) {
instance = new WorkbenchBrowserSupport();
}
return instance;
}
/* (non-Javadoc)
* @see org.eclipse.ui.browser.IWorkbenchBrowserSupport#createBrowser(int, java.lang.String, java.lang.String, java.lang.String)
*/
public IWebBrowser createBrowser(int style, String browserId, String name,
String tooltip) throws PartInitException {
return getActiveSupport()
.createBrowser(style, browserId, name, tooltip);
}
/* (non-Javadoc)
* @see org.eclipse.ui.browser.IWorkbenchBrowserSupport#createBrowser(java.lang.String)
*/
public IWebBrowser createBrowser(String browserId) throws PartInitException {
return getActiveSupport().createBrowser(browserId);
}
/* (non-Javadoc)
* @see org.eclipse.ui.browser.IWorkbenchBrowserSupport#isInternalWebBrowserAvailable()
*/
public boolean isInternalWebBrowserAvailable() {
return getActiveSupport().isInternalWebBrowserAvailable();
}
private IWorkbenchBrowserSupport getActiveSupport() {
if (initialized == false) {
loadActiveSupport();
}
// ensure we always have an active instance
if (activeSupport == null) {
activeSupport = new DefaultWorkbenchBrowserSupport();
}
return activeSupport;
}
/**
* Answers whether the system has a non-default browser installed.
*
* @return whether the system has a non-default browser installed
*/
public boolean hasNonDefaultBrowser() {
return !(getActiveSupport() instanceof DefaultWorkbenchBrowserSupport);
}
private void loadActiveSupport() {
BusyIndicator.showWhile(Display.getCurrent(), new Runnable() {
/*
* (non-Javadoc)
*
* @see java.lang.Runnable#run()
*/
public void run() {
IConfigurationElement[] elements = Platform
.getExtensionRegistry().getConfigurationElementsFor(
PlatformUI.PLUGIN_ID,
IWorkbenchRegistryConstants.PL_BROWSER_SUPPORT);
IConfigurationElement elementToUse = null;
if (desiredBrowserSupportId != null) {
elementToUse = findDesiredElement(elements);
} else {
elementToUse = getElementToUse(elements);
}
if (elementToUse != null) {
initialized = initializePluggableBrowserSupport(elementToUse);
}
}
/**
* Search for the element whose extension has ID equal to that of
* the field desiredBrowserSupport.
*
* @param elements
* the elements to search
* @return the element or <code>null</code>
*/
private IConfigurationElement findDesiredElement(IConfigurationElement [] elements) {
for (int i = 0; i < elements.length; i++) {
if (desiredBrowserSupportId.equals(elements[i].getDeclaringExtension().getUniqueIdentifier())) {
return elements[i];
}
}
return null;
}
private IExtensionPoint getExtensionPoint() {
return Platform.getExtensionRegistry()
.getExtensionPoint(PlatformUI.PLUGIN_ID, IWorkbenchRegistryConstants.PL_BROWSER_SUPPORT);
}
private IConfigurationElement getElementToUse(
IConfigurationElement[] elements) {
if (elements.length == 0) {
return null;
}
IConfigurationElement defaultElement = null;
IConfigurationElement choice = null;
// find the first default element and
// the first non-default element. If non-default
// is found, pick it. Otherwise, use default.
for (int i = 0; i < elements.length; i++) {
IConfigurationElement element = elements[i];
if (element.getName().equals(IWorkbenchRegistryConstants.TAG_SUPPORT)) {
String def = element.getAttribute(IWorkbenchRegistryConstants.ATT_DEFAULT);
if (def != null && Boolean.valueOf(def).booleanValue()) {
if (defaultElement == null) {
defaultElement = element;
}
} else {
// non-default
if (choice == null) {
choice = element;
}
}
}
}
if (choice == null) {
choice = defaultElement;
}
return choice;
}
private boolean initializePluggableBrowserSupport(
IConfigurationElement element) {
// Instantiate the browser support
try {
activeSupport = (AbstractWorkbenchBrowserSupport) WorkbenchPlugin
.createExtension(element, IWorkbenchRegistryConstants.ATT_CLASS);
// start listening for removals
IExtensionTracker extensionTracker = PlatformUI.getWorkbench().getExtensionTracker();
extensionTracker.registerHandler(handler, ExtensionTracker
.createExtensionPointFilter(getExtensionPoint()));
// register the new browser support for removal
// notification
extensionTracker
.registerObject(element.getDeclaringExtension(),
activeSupport, IExtensionTracker.REF_WEAK);
return true;
} catch (CoreException e) {
WorkbenchPlugin
.log("Unable to instantiate browser support" + e.getStatus(), e);//$NON-NLS-1$
}
return false;
}
});
}
/**
* For debug purposes only.
*
* @param desiredBrowserSupportId the desired browser system id
*/
public void setDesiredBrowserSupportId(String desiredBrowserSupportId) {
dispose(); // prep for a new help system
this.desiredBrowserSupportId = desiredBrowserSupportId;
}
/**
* Dispose of the active support.
*/
protected void dispose() {
activeSupport = null;
initialized = false;
}
}
