actionbutton.java

来自「JfreeChart 常用图表例子」· Java 代码 · 共 276 行

/* ========================================================================
 * JCommon : a free general purpose class library for the Java(tm) platform
 * ========================================================================
 *
 * (C) Copyright 2000-2004, by Object Refinery Limited and Contributors.
 * 
 * Project Info:  http://www.jfree.org/jcommon/index.html
 *
 * 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., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307, USA.
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
 * in the United States and other countries.]
 * 
 * -----------------
 * ActionButton.java
 * -----------------
 * (C)opyright 2002-2004, by Thomas Morgner and Contributors.
 *
 * Original Author:  Thomas Morgner;
 * Contributor(s):   David Gilbert (for Object Refinery Limited);
 *
 * $Id: ActionButton.java,v 1.4 2004/11/18 16:34:07 mungady Exp $
 *
 * ChangeLog
 * ---------
 * 30-Aug-2002 : Initial version
 * 01-Sep-2002 : Documentation
 * 10-Dec-2002 : Minor Javadoc updates (DG);
 * 07-Jun-2004 : Corrected source headers (DG);
 *
 */

package org.jfree.ui.action;

import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;

import javax.swing.Action;
import javax.swing.Icon;
import javax.swing.JButton;
import javax.swing.KeyStroke;

import org.jfree.util.Log;

/**
 * The ActionButton is used to connect an Action and its properties to a Button. This functionality
 * is already implemented in JDK 1.3 but needed for JDK 1.2.2 compatibility.
 *
 * @author Thomas Morgner
 */
public class ActionButton extends JButton {

    /**
     * The action.
     */
    private Action action;

    /**
     * The property change handler.
     */
    private ActionEnablePropertyChangeHandler propertyChangeHandler;

    /**
     * Helperclass to handle the property change event raised by the action. Changed properties in
     * the action will affect the button.
     */
    private class ActionEnablePropertyChangeHandler implements PropertyChangeListener {

        /**
         * Default constructor.
         */
        public ActionEnablePropertyChangeHandler() {
        }

        /**
         * Receives notification of a property change event.
         *
         * @param event the property change event.
         */
        public void propertyChange(final PropertyChangeEvent event) {
            try {
                if (event.getPropertyName().equals("enabled")) {
                    setEnabled(getAction().isEnabled());
                }
                else if (event.getPropertyName().equals(Action.SMALL_ICON)) {
                    setIcon((Icon) getAction().getValue(Action.SMALL_ICON));
                }
                else if (event.getPropertyName().equals(Action.NAME)) {
                    setText((String) getAction().getValue
                        (Action.NAME));
                }
                else if (event.getPropertyName().equals(Action.SHORT_DESCRIPTION)) {
                    ActionButton.this.setToolTipText((String)
                        getAction().getValue(Action.SHORT_DESCRIPTION));
                }

                final Action ac = getAction();
                if (event.getPropertyName().equals(ActionDowngrade.ACCELERATOR_KEY)) {
                    final KeyStroke oldVal = (KeyStroke) event.getOldValue();
                    if (oldVal != null) {
                        unregisterKeyboardAction
                            (oldVal);
                    }
                    final Object o = ac.getValue(ActionDowngrade.ACCELERATOR_KEY);
                    if (o instanceof KeyStroke) {
                        final KeyStroke k = (KeyStroke) o;
                        registerKeyboardAction(ac, k, WHEN_IN_FOCUSED_WINDOW);
                    }
                }
                else if (event.getPropertyName().equals(ActionDowngrade.MNEMONIC_KEY)) {
                    final Object o = ac.getValue(ActionDowngrade.MNEMONIC_KEY);
                    if (o != null) {
                        if (o instanceof Character) {
                            final Character c = (Character) o;
                            setMnemonic(c.charValue());
                        }
                        else if (o instanceof Integer) {
                            final Integer c = (Integer) o;
                            setMnemonic(c.intValue());
                        }
                    }
                }
            }
            catch (Exception e) {
                Log.warn("Error on PropertyChange in ActionButton: ", e);
            }
        }
    }

    /**
     * Creates a Button without any text and without an assigned Action.
     */
    public ActionButton() {
        super();
    }

    /**
     * Creates a Button and set the given text as label.
     *
     * @param text the label for the new button.
     */
    public ActionButton(final String text) {
        super(text);
    }

    /**
     * Creates an ActionButton and sets the given text and icon on the button.
     *
     * @param text the label for the new button.
     * @param icon the icon for the button.
     */
    public ActionButton(final String text, final Icon icon) {
        super(text, icon);
    }


    /**
     * Creates an ActionButton and sets the given icon on the button.
     *
     * @param icon the icon for the button.
     */
    public ActionButton(final Icon icon) {
        super(icon);
    }

    /**
     * Nreates an ActionButton and assigns the given action with the button.
     *
     * @param action the action.
     */
    public ActionButton(final Action action) {
        setAction(action);
    }

    /**
     * Returns the assigned action or null if no action has been assigned.
     *
     * @return the action (possibly null).
     */
    public Action getAction() {
        return this.action;
    }


    /**
     * Returns and initializes the PropertyChangehandler for this ActionButton.
     * The PropertyChangeHandler monitors the action and updates the button if necessary.
     *
     * @return the property change handler.
     */
    private ActionEnablePropertyChangeHandler getPropertyChangeHandler() {
        if (this.propertyChangeHandler == null) {
            this.propertyChangeHandler = new ActionEnablePropertyChangeHandler();
        }
        return this.propertyChangeHandler;
    }

    /**
     * Enables and disables this button and if an action is assigned to this button the
     * propertychange is forwarded to the assigned action.
     *
     * @param b the new enable-state of this button
     */
    public void setEnabled(final boolean b) {
        super.setEnabled(b);
        if (getAction() != null) {
            getAction().setEnabled(b);
        }
    }

    /**
     * Assigns the given action to this button. The properties of the action will be assigned to
     * the button. If an previous action was set, the old action is unregistered.
     * <p/>
     * <ul>
     * <li>NAME - specifies the button text
     * <li>SMALL_ICON - specifies the buttons icon
     * <li>MNEMONIC_KEY - specifies the buttons mnemonic key
     * <li>ACCELERATOR_KEY - specifies the buttons accelerator
     * </ul>
     *
     * @param newAction the new action
     */
    public void setAction(final Action newAction) {
        final Action oldAction = getAction();
        if (oldAction != null) {
            removeActionListener(oldAction);
            oldAction.removePropertyChangeListener(getPropertyChangeHandler());

            final Object o = oldAction.getValue(ActionDowngrade.ACCELERATOR_KEY);
            if (o instanceof KeyStroke) {
                final KeyStroke k = (KeyStroke) o;
                unregisterKeyboardAction(k);
            }
        }
        this.action = newAction;
        if (this.action != null) {
            addActionListener(newAction);
            newAction.addPropertyChangeListener(getPropertyChangeHandler());

            setText((String) (newAction.getValue(Action.NAME)));
            setToolTipText((String) (newAction.getValue(Action.SHORT_DESCRIPTION)));
            setIcon((Icon) newAction.getValue(Action.SMALL_ICON));
            setEnabled(this.action.isEnabled());

            Object o = newAction.getValue(ActionDowngrade.MNEMONIC_KEY);
            if (o != null) {
                if (o instanceof Character) {
                    final Character c = (Character) o;
                    setMnemonic(c.charValue());
                }
                else if (o instanceof Integer) {
                    final Integer c = (Integer) o;
                    setMnemonic(c.intValue());
                }
            }
            o = newAction.getValue(ActionDowngrade.ACCELERATOR_KEY);
            if (o instanceof KeyStroke) {
                final KeyStroke k = (KeyStroke) o;
                registerKeyboardAction(newAction, k, WHEN_IN_FOCUSED_WINDOW);
            }
        }
    }
}