PlatformUI.java

/*******************************************************************************
 * Copyright (c) 2000, 2006 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 org.eclipse.jface.preference.IPreferenceStore;
import org.eclipse.swt.widgets.Display;
import org.eclipse.ui.internal.WorkbenchMessages;
import org.eclipse.ui.testing.TestableObject;

/**
 * The central class for access to the Eclipse Platform User Interface. This
 * class cannot be instantiated; all functionality is provided by static
 * methods.
 * 
 * Features provided:
 * <ul>
 * <li>creation of the workbench.</li>
 * <li>access to the workbench.</li>
 * </ul>
 * <p>
 * 
 * @see IWorkbench
 */
public final class PlatformUI {
	/**
	 * Identifies the workbench plug-in.
	 */
	public static final String PLUGIN_ID = "org.eclipse.ui"; //$NON-NLS-1$

	/**
	 * Return code (value 0) indicating that the workbench terminated normally.
	 * 
	 * @see #createAndRunWorkbench
	 * @since 3.0
	 */
	public static final int RETURN_OK = 0;

	/**
	 * Return code (value 1) indicating that the workbench was terminated with a
	 * call to <code>IWorkbench.restart</code>.
	 * 
	 * @see #createAndRunWorkbench
	 * @see IWorkbench#restart
	 * @since 3.0
	 */
	public static final int RETURN_RESTART = 1;

	/**
	 * Return code (value 2) indicating that the workbench failed to start.
	 * 
	 * @see #createAndRunWorkbench
	 * @see IWorkbench#restart
	 * @since 3.0
	 */
	public static final int RETURN_UNSTARTABLE = 2;

	/**
	 * Return code (value 3) indicating that the workbench was terminated with a
	 * call to IWorkbenchConfigurer#emergencyClose.
	 * 
	 * @see #createAndRunWorkbench
	 * @since 3.0
	 */
	public static final int RETURN_EMERGENCY_CLOSE = 3;

	/**
	 * Block instantiation.
	 */
	private PlatformUI() {
		// do nothing
	}

	/**
	 * Returns the workbench. Fails if the workbench has not been created yet.
	 * 
	 * @return the workbench
	 */
	public static IWorkbench getWorkbench() {
		if (Workbench.getInstance() == null) {
			// app forgot to call createAndRunWorkbench beforehand
			throw new IllegalStateException(
					WorkbenchMessages.PlatformUI_NoWorkbench);
		}
		return Workbench.getInstance();
	}

	/**
	 * Returns whether {@link #createAndRunWorkbench createAndRunWorkbench} has
	 * been called to create the workbench, and the workbench has yet to
	 * terminate.
	 * <p>
	 * Note that this method may return <code>true</code> while the workbench is
	 * still being initialized, so it may not be safe to call workbench API
	 * methods even if this method returns true. See bug 49316 for details.
	 * </p>
	 * 
	 * @return <code>true</code> if the workbench has been created and is still
	 *         running, and <code>false</code> if the workbench has not yet been
	 *         created or has completed
	 * @since 3.0
	 */
	public static boolean isWorkbenchRunning() {
		return Workbench.getInstance() != null
				&& Workbench.getInstance().isRunning();
	}

	/**
	 * Creates the workbench and associates it with the given display and
	 * workbench advisor, and runs the workbench UI. This entails processing and
	 * dispatching events until the workbench is closed or restarted.
	 * <p>
	 * This method is intended to be called by the main class (the
	 * "application"). Fails if the workbench UI has already been created.
	 * </p>
	 * <p>
	 * Use {@link #createDisplay createDisplay} to create the display to pass
	 * in.
	 * </p>
	 * <p>
	 * Note that this method is intended to be called by the application (
	 * <code>org.eclipse.core.boot.IPlatformRunnable</code>). It must be called
	 * exactly once, and early on before anyone else asks
	 * <code>getWorkbench()</code> for the workbench.
	 * </p>
	 * 
	 * @param display
	 *            the display to be used for all UI interactions with the
	 *            workbench
	 * @param advisor
	 *            the application-specific advisor that configures and
	 *            specializes the workbench
	 * @return return code {@link #RETURN_OK RETURN_OK} for normal exit;
	 *         {@link #RETURN_RESTART RETURN_RESTART} if the workbench was
	 *         terminated with a call to {@link IWorkbench#restart
	 *         IWorkbench.restart}; {@link #RETURN_UNSTARTABLE
	 *         RETURN_UNSTARTABLE} if the workbench could not be started;
	 *         {@link #RETURN_EMERGENCY_CLOSE RETURN_EMERGENCY_CLOSE} if the UI
	 *         quit because of an emergency; other values reserved for future
	 *         use
	 * @since 3.0
	 */
	public static int createAndRunWorkbench(Display display,
			WorkbenchAdvisor advisor) {
		return Workbench.createAndRunWorkbench(display, advisor);
	}

	/**
	 * Creates the <code>Display</code> to be used by the workbench. It is the
	 * caller's responsibility to dispose the resulting <code>Display</code>,
	 * not the workbench's.
	 * 
	 * @return the display
	 * @since 3.0
	 */
	public static Display createDisplay() {
		return Workbench.createDisplay();
	}

	/**
	 * Returns the testable object facade, for use by the test harness.
	 * <p>
	 * IMPORTANT: This method is only for use by the test harness. Applications
	 * and regular plug-ins should not call this method.
	 * </p>
	 * 
	 * @return the testable object facade
	 * @since 3.0
	 */
	public static TestableObject getTestableObject() {
		return Workbench.getWorkbenchTestable();
	}

	/**
	 * Returns the preference store used for publicly settable workbench
	 * preferences. Constants for these preferences are defined on
	 * {@link org.eclipse.ui.IWorkbenchPreferenceConstants}.
	 * 
	 * @return the workbench public preference store
	 * @since 3.0
	 */
	public static IPreferenceStore getPreferenceStore() {
		return PrefUtil.getAPIPreferenceStore();
	}
}