AbstractPreferencesDialog.java

/**
 * Copyright 1999-2009 The Pegadi Team
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/**
 * Dialog for preferences.
 *
 * @author Håvard Wigtil <havardw at pvv.org>
 */

package org.pegadi.swing;


import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Properties;
import java.util.ResourceBundle;


public abstract class AbstractPreferencesDialog extends JDialog {

    protected Logger log = LoggerFactory.getLogger(getClass());

    /** The preferences, as given to this dialog. */
    protected Properties prefs;

    /** The preferences that were changed. This is only set after
        the dialog is closed. */
    protected Properties changedPrefs;

    /** <code>true</code> if OK was pressed to close the dialog. */
    protected boolean okResult;

    /** UI strings. */
    protected ResourceBundle apdStrings;


    /**
     * Create a new dialog without any preferences set.
     */
    public AbstractPreferencesDialog() {
        this(null, new Properties());
    }


    /**
     * Creates a new dialog, and calls <code>setPreferences</code>
     * to populate the dialog with existing / default preferences.
     * The dialog will be modal by default.
     */
    public AbstractPreferencesDialog(Frame parent, Properties preferences) {
        super(parent, true);
        changedPrefs = null;
        okResult     = false;
        apdStrings   = ResourceBundle.getBundle("org.pegadi.swing.AbstractPreferencesDialog");

        createUI();
        setPreferences(preferences);
    }


    /**
     * Returns the changed preferences. Will return <code>null</code> if called
     * before the dialog is closed, or if called when the dialog was cancelled.
     * When "OK" was pressed, this will always return a valid
     * <code>Properties</code> object, even when no preferences were changed.
     *
     * @return changed preferences, or <code>null</code>.
     */
    public Properties getChangedPreferences() {
        return changedPrefs;
    }


    /**
     * Returns <code>true</code> if OK was pressed to close the dialog.
     */
    public boolean okResult() {
        return okResult;
    }


    /**
     * Create the user interface. This will create the buttons at the bottom
     * of the dialog and insert the component from
     * <code>createPreferencesPane</code>.
     *
     * @see #createPreferencesPane
     */
    protected void createUI() {
        setTitle(apdStrings.getString("dialog_title"));
        JButton okButton = new JButton(apdStrings.getString("button_OK"));
        okButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                okButton_actionPerformed(e);
            }
        });
        JButton cancelButton = new JButton(apdStrings.getString("button_cancel"));
        cancelButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                cancelButton_actionPerformed(e);
            }
        });

        JPanel buttonPanel = new JPanel(new FlowLayout());
        buttonPanel.add(cancelButton);
        buttonPanel.add(okButton);


        getContentPane().add(buttonPanel, BorderLayout.SOUTH);
        getContentPane().add(createPreferencesPane(), BorderLayout.CENTER);
        pack();
    }


    /**
     * Called when the "OK" button is pressed. This method will call
     * <code>findChangedPreferences</code> gather all changed
     * preferences.
     *
     * @see #findChangedPreferences
     * @param e  The event from the press.
     */
    protected void okButton_actionPerformed(ActionEvent e) {
        findChangedPreferences();
        okResult = true;
        dispose();
    }


    /**
     * Called when the "Cancel" button is pressed.
     *
     * @param e  The event from the press.
     */
    protected void cancelButton_actionPerformed(ActionEvent e) {
        dispose();
    }

    /**
     * This method will be called to create the body of the dialog,
     * the part added above the buttons.
     *
     * @return  The component that will be added.
     */
    protected abstract Component createPreferencesPane();


    /**
     * Set preferences controls according to this <code>Properties</code>.
     * The <code>Properties</code> object will also be set as the new
     * <code>prefs</code> variable.
     */
    public abstract void setPreferences(Properties preferences);


    /**
     * Called when "OK" is pressed to determine which preferences are changed.
     * All changed preferences will be placed in <code>changedPrefs</code>, which
     * prior to this call will be <code>null</code>.
     */
    protected abstract void findChangedPreferences();
}