com.lowagie.rups.view.Console Maven / Gradle / Ivy

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/*
 * $Id: Console.java 3242 2008-04-13 23:00:20Z xlv $
 *
 * Copyright 2007 Bruno Lowagie.
 *
 * 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

package com.lowagie.rups.view;

import java.awt.Color;
import java.io.IOException;
import java.io.PipedInputStream;
import java.io.PipedOutputStream;
import java.io.PrintStream;
import java.util.Observable;
import java.util.Observer;
import javax.swing.JTextPane;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.DefaultStyledDocument;
import javax.swing.text.Document;
import javax.swing.text.Style;
import javax.swing.text.StyleConstants;
import javax.swing.text.StyleContext;

/**
 * A Class that redirects everything written to System.out and System.err to a JTextPane.
 */
public class Console implements Observer {

    /**
     * Single Console instance.
     */
    private static Console console = null;

    /**
     * Custom PrintStream.
     */
    PrintStream printStream;
    /**
     * Custom OutputStream.
     */
    PipedOutputStream poCustom;
    /**
     * Custom InputStream.
     */
    PipedInputStream piCustom;

    /**
     * OutputStream for System.out.
     */
    PipedOutputStream poOut;
    /**
     * InputStream for System.out.
     */
    PipedInputStream piOut;

    /**
     * OutputStream for System.err.
     */
    PipedOutputStream poErr;
    /**
     * InputStream for System.err.
     */
    PipedInputStream piErr;

    /**
     * The StyleContext for the Console.
     */
    ConsoleStyleContext styleContext = new ConsoleStyleContext();

    /**
     * The text area to which everything is written.
     */
    JTextPane textArea = new JTextPane(new DefaultStyledDocument(styleContext));

    /**
     * Creates a new Console object.
     *
     * @throws IOException
     */
    private Console() throws IOException {
        // Set up Custom
        piCustom = new PipedInputStream();
        poCustom = new PipedOutputStream();
        printStream = new PrintStream(poCustom);

        // Set up System.out
        piOut = new PipedInputStream();
        poOut = new PipedOutputStream(piOut);
        System.setOut(new PrintStream(poOut, true));

        // Set up System.err
        piErr = new PipedInputStream();
        poErr = new PipedOutputStream(piErr);
        System.setErr(new PrintStream(poErr, true));

        // Add a scrolling text area
        textArea.setEditable(false);

        // Create reader threads
        new ReadWriteThread(piCustom, ConsoleStyleContext.CUSTOM).start();
        new ReadWriteThread(piOut, ConsoleStyleContext.SYSTEMOUT).start();
        new ReadWriteThread(piErr, ConsoleStyleContext.SYSTEMERR).start();
    }

    /**
     * Console is a Singleton class: you can only get one Console.
     *
     * @return the Console
     */
    public static synchronized Console getInstance() {
        if (console == null) {
            try {
                console = new Console();
            } catch (IOException e) {
                console = null;
            }
        }
        return console;
    }

    /**
     * Allows you to print something to the custom PrintStream.
     *
     * @param s the message you want to send to the Console
     */
    public static void println(String s) {
        PrintStream ps = getInstance().getPrintStream();
        if (ps == null) {
            System.out.println(s);
        } else {
            ps.println(s);
            ps.flush();
        }
    }

    /**
     * @see java.util.Observer#update(java.util.Observable, java.lang.Object)
     */
    public void update(Observable observable, Object obj) {
        if (RupsMenuBar.CLOSE.equals(obj)) {
            textArea.setText("");
        }
        if (RupsMenuBar.OPEN.equals(obj)) {
            textArea.setText("");
        }
    }

    /**
     * Get the custom PrintStream of the console.
     *
     * @return the PrintStream
     */
    public PrintStream getPrintStream() {
        return printStream;
    }

    /**
     * Get the JTextArea to which everything is written.
     *
     * @return the JTextArea
     */
    public JTextPane getTextArea() {
        return textArea;
    }

    /**
     * The thread that will write everything to the text area.
     */
    class ReadWriteThread extends Thread {

        /**
         * The InputStream of this Thread
         */
        PipedInputStream pi;
        /**
         * The type (CUSTOM, SYSTEMOUT, SYSTEMERR) of this Thread
         */
        String type;

        /**
         * Create the ReaderThread.
         */
        ReadWriteThread(PipedInputStream pi, String type) {
            super();
            this.pi = pi;
            this.type = type;
        }

        /**
         * @see java.lang.Thread#run()
         */
        public void run() {
            final byte[] buf = new byte[1024];

            while (true) {
                try {
                    final int len = pi.read(buf);
                    if (len == -1) {
                        break;
                    }
                    Document doc = textArea.getDocument();
                    AttributeSet attset = styleContext.getStyle(type);
                    String snippet = new String(buf, 0, len);
                    doc.insertString(doc.getLength(),
                            snippet, attset);
                    printStream.print(snippet);
                    textArea.setCaretPosition(textArea.getDocument().getLength());
                } catch (BadLocationException | IOException ignored) {
                    // ignored
                }
            }
        }
    }

    /**
     * The style context defining the styles of each type of PrintStream.
     */
    class ConsoleStyleContext extends StyleContext {

        /**
         * The name of the Style used for Custom messages
         */
        public static final String CUSTOM = "Custom";
        /**
         * The name of the Style used for System.out
         */
        public static final String SYSTEMOUT = "SystemOut";
        /**
         * The name of the Style used for System.err
         */
        public static final String SYSTEMERR = "SystemErr";
        /**
         * A Serial Version UID.
         */
        private static final long serialVersionUID = 7253870053566811171L;

        /**
         * Creates the style context for the Console.
         */
        public ConsoleStyleContext() {
            super();
            Style root = getStyle(DEFAULT_STYLE);
            Style s = addStyle(CUSTOM, root);
            StyleConstants.setForeground(s, Color.BLACK);
            s = addStyle(SYSTEMOUT, root);
            StyleConstants.setForeground(s, Color.GREEN);
            s = addStyle(SYSTEMERR, root);
            StyleConstants.setForeground(s, Color.RED);
        }
    }
}