// $Header: /home/cvs/jakarta-jmeter/src/jorphan/org/apache/jorphan/gui/JLabeledTextArea.java,v 1.6 2004/02/11 23:48:32 sebb Exp $
/*
 * Copyright 2001-2004 The Apache Software Foundation.
 *
 * 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.
 * 
*/

package org.apache.jorphan.gui;

import java.awt.BorderLayout;
import java.awt.event.FocusEvent;
import java.awt.event.FocusListener;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;

import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
import javax.swing.text.Document;

/**
 * A Helper component that wraps a JTextField with a label into a JPanel
 * (this). This component also has an efficient event handling mechanism for
 * handling the text changing in the Text Field. The registered change
 * listeners are only called when the text has changed.
 *
 * @author S.Coleman
 * @version $Revision: 1.6 $
 */
public class JLabeledTextArea
    extends JPanel
    implements JLabeledField, FocusListener
{
    private JLabel mLabel;
    private JTextArea mTextArea;

    // Maybe move to vector if MT problems occur
    private ArrayList mChangeListeners = new ArrayList(3);

    // A temporary cache for the focus listener
    private String oldValue = "";
    
    /**
     * Default constructor, The label and the Text field are left empty.
     */
    public JLabeledTextArea()
    {
        this("", null);
    }

    /**
     * Constructs a new component with the label displaying the
     * passed text.
     *
     * @param pLabel The text to in the label.
     */
    public JLabeledTextArea(String pLabel, Document docModel)
    {
        super();
        mLabel = new JLabel(pLabel);
        if (docModel != null)
        {
            setDocumentModel(docModel);
        }
        init();
    }

    public List getComponentList()
    {
        List comps = new LinkedList();
        comps.add(mLabel);
        comps.add(mTextArea);
        return comps;
    }

    public void setDocumentModel(Document docModel)
    {
        mTextArea.setDocument(docModel);
    }

    /**
     * Initialises all of the components on this panel.
     */
    private void init()
    {
        setLayout(new BorderLayout());

        mTextArea = new JTextArea();
        mTextArea.setRows(4);
        mTextArea.setLineWrap(true);
        mTextArea.setWrapStyleWord(true);
        // Register the handler for focus listening. This handler will
        // only notify the registered when the text changes from when
        // the focus is gained to when it is lost.
        mTextArea.addFocusListener(this);

        // Add the sub components
        this.add(mLabel, BorderLayout.NORTH);
        this.add(new JScrollPane(mTextArea), BorderLayout.CENTER);
    }

    /**
     * Callback method when the focus to the Text Field component
     * is lost.
     *
     * @param pFocusEvent The focus event that occured.
     */
    public void focusLost(FocusEvent pFocusEvent)
    {
         // Compare if the value has changed, since we received focus.
         if (!oldValue.equals(mTextArea.getText()))
         {
              notifyChangeListeners();
         }
    }
    
    /**
     * Catch what the value was when focus was gained.
     */
    public void focusGained(FocusEvent pFocusEvent)
    {
         oldValue = mTextArea.getText();
    }

    /**
     * Set the text displayed in the label.
     *
     * @param pLabel The new label text.
     */
    public void setLabel(String pLabel)
    {
        mLabel.setText(pLabel);
    }

    /**
     * Set the text displayed in the Text Field.
     *
     * @param pText The new text to display in the text field.
     */
    public void setText(String pText)
    {
        mTextArea.setText(pText);
    }

    /**
     * Returns the text in the Text Field.
     *
     * @return The text in the Text Field.
     */
    public String getText()
    {
        return mTextArea.getText();
    }

    /**
     * Returns the text of the label.
     *
     * @return The text of the label.
     */
    public String getLabel()
    {
        return mLabel.getText();
    }

    /**
     * Adds a change listener, that will be notified when the text in the
     * text field is changed. The ChangeEvent that will be passed
     * to registered listeners will contain this object as the source, allowing
     * the new text to be extracted using the {@link #getText() getText} method.
     *
     * @param pChangeListener The listener to add
     */
    public void addChangeListener(ChangeListener pChangeListener)
    {
        mChangeListeners.add(pChangeListener);
    }

    /**
     * Removes a change listener.
     *
     * @param pChangeListener The change listener to remove.
     */
    public void removeChangeListener(ChangeListener pChangeListener)
    {
        mChangeListeners.remove(pChangeListener);
    }

    /**
     * Notify all registered change listeners that the
     * text in the text field has changed.
     */
    private void notifyChangeListeners()
    {
        ChangeEvent ce = new ChangeEvent(this);
        for (int index = 0; index < mChangeListeners.size(); index++)
        {
            ((ChangeListener) mChangeListeners.get(index)).stateChanged(ce);
        }
    }
}