textareaoutputstream.java

无线传感器网络节点Sun SPOT管理工具

/*
 * Copyright (c) 2007 Sun Microsystems, Inc. All rights reserved. 
 * 
 * Sun Microsystems, Inc. has intellectual property rights relating to technology embodied in the product that is
 * described in this document. In particular, and without limitation, these intellectual property rights may
 * include one or more of the U.S. patents listed at http://www.sun.com/patents and one or more additional patents
 * or pending patent applications in the U.S. and in other countries.
 * 
 * U.S. Government Rights - Commercial software. Government users are subject to the Sun Microsystems, Inc.
 * standard license agreement and applicable provisions of the FAR and its supplements.
 * 
 * Use is subject to license terms. 
 * 
 * This distribution may include materials developed by third parties. Sun, Sun Microsystems, the Sun logo and
 * Java are trademarks or registered trademarks of Sun Microsystems, Inc. in the U.S. and other countries. 
 * 
 * Copyright (c) 2006 Sun Microsystems, Inc. Tous droits r?serv?s.
 * 
 * Sun Microsystems, Inc. d?tient les droits de propri?t? intellectuels relatifs ? la technologie incorpor?e dans
 * le produit qui est d?crit dans ce document. En particulier, et ce sans limitation, ces droits de propri?t?
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 * et un ou les brevets suppl?mentaires ou les applications de brevet en attente aux Etats - Unis et dans les
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 * L'utilisation est soumise aux termes du contrat de licence.
 * 
 * Cette distribution peut comprendre des composants d?velopp?s par des tierces parties.
 * Sun, Sun Microsystems, le logo Sun et Java sont des marques de fabrique ou des marques d?pos?es de Sun
 * Microsystems, Inc. aux Etats-Unis et dans d'autres pays.
 */

package com.sun.spot.spotworld.gui;

import java.io.*;
import java.awt.*;
import javax.swing.*;

/**
 * A helper class to display an OutputStream in a JTextArea of a GUI.
 *
 * @author Ron Goldman
 */
public class TextAreaOutputStream extends OutputStream {
    
    private JTextArea textArea;
    private JScrollPane scrollPane;
    private JScrollBar scrollBar = null;
    private char[] buf = new char[1];
    
    /**
     * Creates a new instance of a TextAreaOutputStream that will display in a JTextArea.
     * Assumes that the JTextArea is embedded in a JScrollPane.
     *
     * @param sp the JScrollPane containing the JTextArea
     */
    public TextAreaOutputStream(JScrollPane sp) {
        textArea = (JTextArea)sp.getViewport().getView();
        textArea.setFont(Font.decode("Courier"));
        scrollPane = sp;
        if (scrollPane != null) {
            scrollBar = scrollPane.getVerticalScrollBar();
        }
    }
    
    /**
     * Creates a new instance of a TextAreaOutputStream that will display in a JTextArea.
     * Assumes that the JTextArea is embedded in a JScrollPane.
     *
     * @param sp the JScrollPane containing the JTextArea
     */
    public TextAreaOutputStream(JTextArea ta) {
        textArea = ta;
        textArea.setFont(Font.decode("Courier"));
        scrollPane = (JScrollPane) ta.getParent().getParent();
        if (scrollPane != null) {
            scrollBar = scrollPane.getVerticalScrollBar();
        }
    }
    /**
     * Appends everything written to the OutputStream to the JTextArea. 
     * Routine checks when inserting a newline if the bottom of the text is
     * curently visible and if so, it automatically scrolls the text region
     * to keep it visible.
     *
     * @param b the character to print out
     *
     */
    public void write(int b) {
        buf[0] = (char)b;
        boolean scrollDown = false;
        if (buf[0] == '\n' && scrollBar != null) {
            int val = scrollBar.getValue();
            int max = scrollBar.getMaximum();
            int size = scrollBar.getVisibleAmount();
            scrollDown = ((val + size) >= ((95 * max) / 100));
        }
        textArea.append(new String(buf));
        
        if (scrollDown) {
            textArea.setCaretPosition(textArea.getDocument().getLength());
        }
    }
    
}