saferunnable.java

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/*******************************************************************************
 * 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
 *     Chris Gross ([e-mail]) - support for ISafeRunnableRunner added
 *       (bug 49497 [RCP] JFace dependency on org.eclipse.core.runtime enlarges standalone JFace applications)
 *******************************************************************************/
package org.eclipse.jface.util;

import org.eclipse.core.runtime.ISafeRunnable;
import org.eclipse.core.runtime.OperationCanceledException;
import org.eclipse.jface.dialogs.MessageDialog;
import org.eclipse.jface.resource.JFaceResources;

/**
 * Implements a default implementation of ISafeRunnable.
 * The default implementation of <code>handleException</code>
 * opens a message dialog.
 * <p><b>Note:<b> This class can open an error dialog and should not 
 *  be used outside of the UI Thread.</p>
 */
public abstract class SafeRunnable implements ISafeRunnable {
    
    private static boolean ignoreErrors = false;
    
    private static ISafeRunnableRunner runner;
    
    private String message;

    /**
     * Creates a new instance of SafeRunnable with a default error message.
     */
    public SafeRunnable() {
        // do nothing
    }

    /**
     * Creates a new instance of SafeRunnable with the given error message.
     * 
     * @param message the error message to use
     */
    public SafeRunnable(String message) {
        this.message = message;
    }

    /* (non-Javadoc)
     * Method declared on ISafeRunnable.
     */
    public void handleException(Throwable e) {
        // Workaround to avoid interactive error dialogs during automated testing
        if (!ignoreErrors) {
            if (message == null) {
				message = JFaceResources.getString("SafeRunnable.errorMessage"); //$NON-NLS-1$
			}
            MessageDialog.openError(null,
                    JFaceResources.getString("error"), message); //$NON-NLS-1$
        }
    }

    /**
     * Flag to avoid interactive error dialogs during automated testing.
     * @deprecated use getIgnoreErrors()
     */
    public static boolean getIgnoreErrors(boolean flag) {
        return ignoreErrors;
    }

    /**
     * Flag to avoid interactive error dialogs during automated testing.
     * 
     * @since 3.0
     */
    public static boolean getIgnoreErrors() {
        return ignoreErrors;
    }

    /**
     * Flag to avoid interactive error dialogs during automated testing.
     */
    public static void setIgnoreErrors(boolean flag) {
        ignoreErrors = flag;
    }
    
	/**
     * Returns the safe runnable runner.
     * 
	 * @return the safe runnable runner
	 * 
	 * @since 3.1
	 */
	public static ISafeRunnableRunner getRunner() {
        if (runner == null) {
            runner = createDefaultRunner();
        }
		return runner;
	}

    /**
     * Creates the default safe runnable runner.
     * 
     * @return the default safe runnable runner
     * @since 3.1
     */
    private static ISafeRunnableRunner createDefaultRunner() {
        return new ISafeRunnableRunner() {
            public void run(ISafeRunnable code) {
                try {
                    code.run();
                } catch (Exception e) {
                    handleException(code, e);
                } catch (LinkageError e) {
                    handleException(code, e);
                }
            }

            private void handleException(ISafeRunnable code, Throwable e) {
                if (!(e instanceof OperationCanceledException)) {
                    e.printStackTrace();
                }
                code.handleException(e);
            }
        };
    }
    
	/**
     * Sets the safe runnable runner.
     *  
	 * @param runner the runner to set, or <code>null</code> to reset to the default runner
	 * @since 3.1
	 */
	public static void setRunner(ISafeRunnableRunner runner) {
		SafeRunnable.runner = runner;
	}

    /**
     * Runs the given safe runnable using the safe runnable runner.
     * This is a convenience method, equivalent to:
     * <code>SafeRunnable.getRunner().run(runnable)</code>.
     * 
     * @param runnable the runnable to run
     * @since 3.1
     */
    public static void run(ISafeRunnable runnable) {
        getRunner().run(runnable);
    }
    
}