swingx-master/swingx-core/src/main/java/org/jdesktop/swingx/plaf/basic/core/LazyActionMap.java
/*
 * $Id$
 *
 * Copyright 2009 Sun Microsystems, Inc., 4150 Network Circle,
 * Santa Clara, California 95054, U.S.A. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */
package org.jdesktop.swingx.plaf.basic.core;


import java.lang.reflect.*;
import javax.swing.*;
import javax.swing.plaf.*;

/**
 * An ActionMap that populates its contents as necessary. The
 * contents are populated by invoking the <code>loadActionMap</code>
 * method on the passed in Object.
 *
 * @version 1.6, 11/17/05
 * @author Scott Violet
 */
public class LazyActionMap extends ActionMapUIResource {
    /**
     * Object to invoke <code>loadActionMap</code> on. This may be
     * a Class object.
     */
    private transient Object _loader;

    /**
     * Installs an ActionMap that will be populated by invoking the
     * <code>loadActionMap</code> method on the specified Class
     * when necessary.
     * <p>
     * This should be used if the ActionMap can be shared.
     *
     * @param c JComponent to install the ActionMap on.
     * @param loaderClass Class object that gets loadActionMap invoked
     *                    on.
     * @param defaultsKey Key to use to defaults table to check for
     *        existing map and what resulting Map will be registered on.
     */
    public static void installLazyActionMap(JComponent c, Class loaderClass,
                                     String defaultsKey) {
        ActionMap map = (ActionMap)UIManager.get(defaultsKey);
        if (map == null) {
            map = new LazyActionMap(loaderClass);
            UIManager.getLookAndFeelDefaults().put(defaultsKey, map);
        }
        SwingUtilities.replaceUIActionMap(c, map);
    }

    /**
     * Returns an ActionMap that will be populated by invoking the
     * <code>loadActionMap</code> method on the specified Class
     * when necessary.
     * <p>
     * This should be used if the ActionMap can be shared.
     *
     * @param c JComponent to install the ActionMap on.
     * @param loaderClass Class object that gets loadActionMap invoked
     *                    on.
     * @param defaultsKey Key to use to defaults table to check for
     *        existing map and what resulting Map will be registered on.
     */
    static ActionMap getActionMap(Class loaderClass,
                                  String defaultsKey) {
        ActionMap map = (ActionMap)UIManager.get(defaultsKey);
        if (map == null) {
            map = new LazyActionMap(loaderClass);
            UIManager.getLookAndFeelDefaults().put(defaultsKey, map);
        }
        return map;
    }


    private LazyActionMap(Class loader) {
        _loader = loader;
    }

    public void put(Action action) {
        put(action.getValue(Action.NAME), action);
    }

    public void put(Object key, Action action) {
        loadIfNecessary();
        super.put(key, action);
    }

    public Action get(Object key) {
        loadIfNecessary();
        return super.get(key);
    }

    public void remove(Object key) {
        loadIfNecessary();
        super.remove(key);
    }

    public void clear() {
        loadIfNecessary();
        super.clear();
    }

    public Object[] keys() {
        loadIfNecessary();
        return super.keys();
    }

    public int size() {
        loadIfNecessary();
        return super.size();
    }

    public Object[] allKeys() {
        loadIfNecessary();
        return super.allKeys();
    }

    public void setParent(ActionMap map) {
        loadIfNecessary();
        super.setParent(map);
    }

    private void loadIfNecessary() {
        if (_loader != null) {
            Object loader = _loader;

            _loader = null;
            Class klass = (Class)loader;
            try {
                Method method = klass.getDeclaredMethod("loadActionMap",
                                      new Class[] { LazyActionMap.class });
                method.invoke(klass, new Object[] { this });
            } catch (NoSuchMethodException nsme) {
                assert false : "LazyActionMap unable to load actions " +
                        klass;
            } catch (IllegalAccessException iae) {
                assert false : "LazyActionMap unable to load actions " +
                        iae;
            } catch (InvocationTargetException ite) {
                assert false : "LazyActionMap unable to load actions " +
                        ite;
            } catch (IllegalArgumentException iae) {
                assert false : "LazyActionMap unable to load actions " +
                        iae;
            }
        }
    }
}
