/*******************************************************************************
* Copyright (c) 2003, 2005 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.help;
import java.net.URL;
import org.eclipse.help.IContext;
/**
* Abstract base class for the help system UI.
* <p>
* The Eclipse platform provides an extension point (<code>"org.eclipse.ui.helpSupport"</code>)
* for plugging in a help system UI. The help system UI is an optional
* component; applications may provide a UI for presenting help to the user by
* implementing a subclass and including the name of their class in the
* <code><config></code> element in an extension to the
* <code>"org.eclipse.ui.helpSupport"</code> extension point.
* </p>
* <p>
* Note that the standard implementation of the help system UI is provided by
* the <code>"org.eclipse.help.ui"</code> plug-in. Since the platform can only
* make use of a single help system UI implementation, make sure that the
* platform is not configured with more than one plug-in trying to extend this
* extension point.
* </p>
*
* @since 3.0
*/
public abstract class AbstractHelpUI {
/**
* Displays the entire help bookshelf.
*/
public abstract void displayHelp();
/**
* Displays the help search facility. For backward compatibility, the
* default implementation does nothing.
*
* @since 3.1
*/
public void displaySearch() {
// do nothing
}
/**
* Displays the dynamic help for the active context. For backward
* compatibility, the default implementation does nothing.
*
* @since 3.1
*/
public void displayDynamicHelp() {
// do nothing
}
/**
* Starts the help search using the help search facility. For backward
* compatibility, the default implementation does nothing.
*
* @param expression
* the search expression
* @since 3.1
*/
public void search(String expression) {
// do nothing
}
/**
* Resolves the help resource href according to the help system
* implementation.
*
* @param href
* the help resource
* @param documentOnly
* if <code>true</code>, the resulting URL must point at the
* document referenced by href. Otherwise, it can be a URL that
* contains additional elements like navigation that the help
* system adds to the document.
* @return the fully resolved URL of the help resource or <code>null</code>
* if not supported. Help systems that use application servers
* typically return URLs with http: protocol. Simple help system
* implementations can return URLs with file: protocol.
*
* @since 3.1
*/
public URL resolve(String href, boolean documentOnly) {
return null;
}
/**
* Displays context-sensitive help for the given context.
* <p>
* (x,y) coordinates specify the location where the context sensitive help
* UI will be presented. These coordinates are screen-relative (ie: (0,0) is
* the top left-most screen corner). The platform is responsible for calling
* this method and supplying the appropriate location.
* </p>
*
* @param context
* the context to display
* @param x
* horizontal position
* @param y
* verifical position
*/
public abstract void displayContext(IContext context, int x, int y);
/**
* Displays help content for the help resource with the given URL.
* <p>
* This method is called by the platform to launch the help system UI,
* displaying the documentation identified by the <code>href</code>
* parameter.
* </p>
* <p>
* The help system makes no guarantee that all the help resources can be
* displayed or how they are displayed.
* </p>
*
* @param href
* the URL of the help resource.
* <p>
* Valid href are as described in
* {@link org.eclipse.help.IHelpResource#getHref() IHelpResource.getHref()}
* </p>
*/
public abstract void displayHelpResource(String href);
/**
* Returns whether the context-sensitive help window is currently being
* displayed.
*
* @return <code>true</code> if the context-sensitive help window is
* currently being displayed, <code>false</code> if not
*/
public abstract boolean isContextHelpDisplayed();
}