Standalone Swing GUI application for demonstrating Regular expressions. : Basic Regular Expressions « Regular Expressions « Java






Standalone Swing GUI application for demonstrating Regular expressions.

Standalone Swing GUI application for demonstrating Regular expressions.
  
/*
 * Copyright (c) Ian F. Darwin, http://www.darwinsys.com/, 1996-2002.
 * All rights reserved. Software written by Ian F. Darwin and others.
 * $Id: LICENSE,v 1.8 2004/02/09 03:33:38 ian Exp $
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 * 
 * Java, the Duke mascot, and all variants of Sun's Java "steaming coffee
 * cup" logo are trademarks of Sun Microsystems. Sun's, and James Gosling's,
 * pioneering role in inventing and promulgating (and standardizing) the Java 
 * language and environment is gratefully acknowledged.
 * 
 * The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
 * inventing predecessor languages C and C++ is also gratefully acknowledged.
 */


import java.awt.GridLayout;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.regex.PatternSyntaxException;

import javax.swing.ButtonGroup;
import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.JTextField;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;

/**
 * Standalone Swing GUI application for demonstrating REs. <br/>TODO: Show the
 * entire match, and $1 and up as captures that matched.
 * 
 * @author Ian Darwin, http://www.darwinsys.com/
 * @version #Id$
 */
public class REDemo extends JPanel {
  protected Pattern pattern;

  protected Matcher matcher;

  protected JTextField patternTF, stringTF;

  protected JCheckBox compiledOK;

  protected JRadioButton match, find, findAll;

  protected JTextField matchesTF;

  /** "main program" method - construct and show */
  public static void main(String[] av) {
    JFrame f = new JFrame("REDemo");
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    REDemo comp = new REDemo();
    f.setContentPane(comp);
    f.pack();
    f.setLocation(200, 200);
    f.setVisible(true);
  }

  /** Construct the REDemo object including its GUI */
  public REDemo() {
    super();

    JPanel top = new JPanel();
    top.add(new JLabel("Pattern:", JLabel.RIGHT));
    patternTF = new JTextField(20);
    patternTF.getDocument().addDocumentListener(new PatternListener());
    top.add(patternTF);
    top.add(new JLabel("Syntax OK?"));
    compiledOK = new JCheckBox();
    top.add(compiledOK);

    ChangeListener cl = new ChangeListener() {
      public void stateChanged(ChangeEvent ce) {
        tryMatch();
      }
    };
    JPanel switchPane = new JPanel();
    ButtonGroup bg = new ButtonGroup();
    match = new JRadioButton("Match");
    match.setSelected(true);
    match.addChangeListener(cl);
    bg.add(match);
    switchPane.add(match);
    find = new JRadioButton("Find");
    find.addChangeListener(cl);
    bg.add(find);
    switchPane.add(find);
    findAll = new JRadioButton("Find All");
    findAll.addChangeListener(cl);
    bg.add(findAll);
    switchPane.add(findAll);

    JPanel strPane = new JPanel();
    strPane.add(new JLabel("String:", JLabel.RIGHT));
    stringTF = new JTextField(20);
    stringTF.getDocument().addDocumentListener(new StringListener());
    strPane.add(stringTF);
    strPane.add(new JLabel("Matches:"));
    matchesTF = new JTextField(3);
    strPane.add(matchesTF);

    setLayout(new GridLayout(0, 1, 5, 5));
    add(top);
    add(strPane);
    add(switchPane);
  }

  protected void setMatches(boolean b) {
    if (b)
      matchesTF.setText("Yes");
    else
      matchesTF.setText("No");
  }

  protected void setMatches(int n) {
    matchesTF.setText(Integer.toString(n));
  }

  protected void tryCompile() {
    pattern = null;
    try {
      pattern = Pattern.compile(patternTF.getText());
      matcher = pattern.matcher("");
      compiledOK.setSelected(true);
    } catch (PatternSyntaxException ex) {
      compiledOK.setSelected(false);
    }
  }

  protected boolean tryMatch() {
    if (pattern == null)
      return false;
    matcher.reset(stringTF.getText());
    if (match.isSelected() && matcher.matches()) {
      setMatches(true);
      return true;
    }
    if (find.isSelected() && matcher.find()) {
      setMatches(true);
      return true;
    }
    if (findAll.isSelected()) {
      int i = 0;
      while (matcher.find()) {
        ++i;
      }
      if (i > 0) {
        setMatches(i);
        return true;
      }
    }
    setMatches(false);
    return false;
  }

  /** Any change to the pattern tries to compile the result. */
  class PatternListener implements DocumentListener {

    public void changedUpdate(DocumentEvent ev) {
      tryCompile();
    }

    public void insertUpdate(DocumentEvent ev) {
      tryCompile();
    }

    public void removeUpdate(DocumentEvent ev) {
      tryCompile();
    }
  }

  /** Any change to the input string tries to match the result */
  class StringListener implements DocumentListener {

    public void changedUpdate(DocumentEvent ev) {
      tryMatch();
    }

    public void insertUpdate(DocumentEvent ev) {
      tryMatch();
    }

    public void removeUpdate(DocumentEvent ev) {
      tryMatch();
    }
  }
}

           
         
    
  








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