bundles/org.eclipse.jface/src/org/eclipse/jface/util/Policy.java

/*******************************************************************************
 * Copyright (c) 2004, 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 (schtoo@schtoo.com) - support for ILogger added
 *       (bug 49497 [RCP] JFace dependency on org.eclipse.core.runtime enlarges standalone JFace applications)
 *******************************************************************************/
package org.eclipse.jface.util;

import java.util.Comparator;

import org.eclipse.core.runtime.IStatus;
import org.eclipse.jface.dialogs.AnimatorFactory;

/**
 * The Policy class handles settings for behaviour, debug flags and logging within JFace.
 * 
 * @since 3.0
 */
public class Policy {

    /**
     * Constant for the the default setting for debug options.
     */
    public static final boolean DEFAULT = false;

    /**
     * The unique identifier of the JFace plug-in.
     */
    public static final String JFACE = "org.eclipse.jface";//$NON-NLS-1$

    private static ILogger log;

    private static Comparator viewerComparator;
    
    private static AnimatorFactory animatorFactory;
    
    /**
     * A flag to indicate whether unparented dialogs should
     * be checked.
     */
    public static boolean DEBUG_DIALOG_NO_PARENT = DEFAULT;

    /**
     * A flag to indicate whether actions are being traced.
     */
    public static boolean TRACE_ACTIONS = DEFAULT;
    
    /**
     * A flag to indicate whether toolbars are being traced.
     */

    public static boolean TRACE_TOOLBAR = DEFAULT;


    /**
     * Returns the dummy log to use if none has been set
     */
    private static ILogger getDummyLog() {
        return new ILogger() {
            public void log(IStatus status) {
                System.err.println(status.getMessage());
            }
        };
    }

    /**
     * Sets the logger used by JFace to log errors.
     * 
     * @param logger the logger to use, or <code>null</code> to use the default logger
     * @since 3.1
     */
    public static void setLog(ILogger logger) {
        log = logger;
    }

    /**
     * Returns the logger used by JFace to log errors.
     * <p>
     * The default logger prints the status to <code>System.err</code>.
     * </p>
     * 
     * @return the logger
     * @since 3.1
     */
    public static ILogger getLog() {
        if (log == null) {
			log = getDummyLog();
		}
        return log;
    }
    
	/**
	 * Return the default comparator used by JFace to sort strings.
	 *  
	 * @return a default comparator used by JFace to sort strings
	 */
	private static Comparator getDefaultComparator(){
		return new Comparator(){
			/**
			 * Compares string s1 to string s2.  
			 * 
			 * @param s1 string 1
			 * @param s2 string 2
			 * @return Returns an integer value. Value is less than zero if source is
			 *         less than target, value is zero if source and target are equal,
			 *         value is greater than zero if source is greater than target.
			 * @exception ClassCastException the arguments cannot be cast to Strings.
			 */
			public int compare(Object s1, Object s2) {
				return ((String)s1).compareTo((String)s2);
			}
		};
	}
	
    /**
     * Return the comparator used by JFace to sort strings.
     *  
     * @return the comparator used by JFace to sort strings
     * @since 3.2 
     */
    public static Comparator getComparator(){
    	if (viewerComparator == null) {
			viewerComparator = getDefaultComparator();
		}
    	return viewerComparator;
    }
    
    /**
     * Sets the comparator used by JFace to sort strings.
     * 
     * @param comparator comparator used by JFace to sort strings
     * @since 3.2
     */
    public static void setComparator(Comparator comparator){
    	Assert.isTrue(viewerComparator == null);
    	viewerComparator = comparator;
    }
    
    /**
	 * Sets the animator factory used by JFace to create control animator
	 * instances. 
	 * 
	 * @param factory the AnimatorFactory to use.
	 * @since 3.2
	 */
	public static void setAnimatorFactory(AnimatorFactory factory){
		animatorFactory = factory;
	}

	/**
	 * Returns the animator factory used by JFace to create control animator
	 * instances. 
	 * 
	 * @return the animator factory used to create control animator instances.
	 * @since 3.2
	 */
	public static AnimatorFactory getAnimatorFactory() {
		if (animatorFactory == null)
			animatorFactory = new AnimatorFactory();
		return animatorFactory;
	}

}