LabelPanel.java

/*******************************************************************************
 * Copyright (c) 1998, 2015 Oracle and/or its affiliates. All rights reserved.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
 * which accompanies this distribution.
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *     Oracle - initial API and implementation from Oracle TopLink
******************************************************************************/
package org.eclipse.persistence.tools.workbench.uitools.swing;

import java.awt.BorderLayout;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;

import javax.swing.BorderFactory;
import javax.swing.Icon;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.border.Border;

import org.eclipse.persistence.tools.workbench.uitools.app.NullPropertyValueModel;
import org.eclipse.persistence.tools.workbench.uitools.app.PropertyValueModel;
import org.eclipse.persistence.tools.workbench.uitools.app.ValueModel;


/**
 * This simple panel is a workaround for JLabels not being model-driven.
 */
public class LabelPanel
    extends JPanel
{
    /**
     * JLabels are not model-driven, so we need to hold on to the label here
     * and set its icon and text explicitly, whenever the models change.
     */
    private JLabel label;


    /**
     * Construct a label (panel) that updates its icon and text in response
     * to changes to the specified models.
     */
    public LabelPanel(PropertyValueModel iconHolder, PropertyValueModel textHolder) {
        super(new BorderLayout());
        this.initialize(iconHolder, textHolder);
    }

    /**
     * Construct a label (panel) that updates its text in response
     * to changes to the specified model. The label will not have an icon.
     */
    public LabelPanel(PropertyValueModel textHolder) {
        this(NullPropertyValueModel.instance(), textHolder);
    }

    protected void initialize(PropertyValueModel iconHolder, PropertyValueModel textHolder) {
        if ((iconHolder == null) || (textHolder == null)) {
            throw new NullPointerException();
        }
        iconHolder.addPropertyChangeListener(ValueModel.VALUE, this.buildIconListener());
        textHolder.addPropertyChangeListener(ValueModel.VALUE, this.buildTextListener());

        this.initializeLayout();

        this.setIcon((Icon) iconHolder.getValue());
        this.setText((String) textHolder.getValue());
    }

    protected PropertyChangeListener buildIconListener() {
        return new PropertyChangeListener() {
            public void propertyChange(PropertyChangeEvent e) {
                LabelPanel.this.setIcon((Icon) e.getNewValue());
            }
            public String toString() {
                return "icon listener";
            }
        };
    }

    protected PropertyChangeListener buildTextListener() {
        return new PropertyChangeListener() {
            public void propertyChange(PropertyChangeEvent e) {
                LabelPanel.this.setText((String) e.getNewValue());
            }
            public String toString() {
                return "text listener";
            }
        };
    }

    protected void initializeLayout() {
        this.label = this.buildLabel();
        this.label.setBorder(this.buildBorder());
        this.add(this.label, BorderLayout.LINE_START);
    }

    protected JLabel buildLabel() {
        return new JLabel();
    }

    protected Border buildBorder() {
        return BorderFactory.createEmptyBorder();
    }

    protected JLabel getLabel() {
        return this.label;
    }

    protected void setText(String text) {
        this.getLabel().setText(text);
    }

    protected void setIcon(Icon icon) {
        this.getLabel().setIcon(icon);
    }

}