content: /*
   * Copyright 1999-2004 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.regexp;
  
  import java.applet.Applet;
  import java.awt.*;
  import java.awt.event.TextEvent;
  import java.awt.event.TextListener;
  import java.awt.event.WindowAdapter;
  import java.awt.event.WindowEvent;
  import java.io.CharArrayWriter;
  import java.io.PrintWriter;
  
  /**
   * Interactive demonstration and testing harness for regular expressions classes.
   * @author <a href="mailto:jonl@muppetlabs.com">Jonathan Locke</a>
   * @version $Id: REDemo.java 126149 2004-02-19 02:35:28Z vgritsenko $
   */
  public class REDemo extends Applet implements TextListener
  {
      /**
       * Matcher and compiler objects
       */
      RE r = new RE();
      REDebugCompiler compiler = new REDebugCompiler();
  
      /**
       * Components
       */
      TextField fieldRE;          // Field for entering regexps
      TextField fieldMatch;       // Field for entering match strings
      TextArea outRE;             // Output of RE compiler
      TextArea outMatch;          // Results of matching operation
  
      /**
       * Add controls and init applet
       */
      public void init()
      {
          // Add components using the dreaded GridBagLayout
          GridBagLayout gb = new GridBagLayout();
          setLayout(gb);
          GridBagConstraints c = new GridBagConstraints();
          c.insets = new Insets(5, 5, 5, 5);
          c.anchor = GridBagConstraints.EAST;
          gb.setConstraints(add(new Label("Regular expression:", Label.RIGHT)), c);
          c.gridy = 0;
          c.anchor = GridBagConstraints.WEST;
          gb.setConstraints(add(fieldRE = new TextField("\\[([:javastart:][:javapart:]*)\\]", 40)), c);
          c.gridx = 0;
          c.gridy = GridBagConstraints.RELATIVE;
          c.anchor = GridBagConstraints.EAST;
          gb.setConstraints(add(new Label("String:", Label.RIGHT)), c);
          c.gridy = 1;
          c.gridx = GridBagConstraints.RELATIVE;
          c.anchor = GridBagConstraints.WEST;
          gb.setConstraints(add(fieldMatch = new TextField("aaa([foo])aaa", 40)), c);
          c.gridy = 2;
          c.gridx = GridBagConstraints.RELATIVE;
          c.fill = GridBagConstraints.BOTH;
          c.weighty = 1.0;
          c.weightx = 1.0;
          gb.setConstraints(add(outRE = new TextArea()), c);
          c.gridy = 2;
          c.gridx = GridBagConstraints.RELATIVE;
          gb.setConstraints(add(outMatch = new TextArea()), c);
  
          // Listen to text changes
          fieldRE.addTextListener(this);
          fieldMatch.addTextListener(this);
  
          // Initial UI update
          textValueChanged(null);
      }
  
      /**
       * Say something into RE text area
       * @param s What to say
       */
      void sayRE(String s)
      {
          outRE.setText(s);
      }
  
      /**
       * Say something into match text area
       * @param s What to say
       */
      void sayMatch(String s)
      {
          outMatch.setText(s);
      }
  
      /**
       * Convert throwable to string
       * @param t Throwable to convert to string
       */
      String throwableToString(Throwable t)
      {
          String s = t.getClass().getName();
          String m;
          if ((m = t.getMessage()) != null)
          {
              s += "\n" + m;
          }
          return s;
      }
  
      /**
       * Change regular expression
       * @param expr Expression to compile
       */
      void updateRE(String expr)
      {
          try
          {
              // Compile program
              r.setProgram(compiler.compile(expr));
  
              // Dump program into RE feedback area
              CharArrayWriter w = new CharArrayWriter();
              compiler.dumpProgram(new PrintWriter(w));
              sayRE(w.toString());
              System.out.println(w);
          }
          catch (Exception e)
          {
              r.setProgram(null);
              sayRE(throwableToString(e));
          }
          catch (Throwable t)
          {
              r.setProgram(null);
              sayRE(throwableToString(t));
          }
      }
  
      /**
       * Update matching info by matching the string against the current
       * compiled regular expression.
       * @param match String to match against
       */
      void updateMatch(String match)
      {
          try
          {
              // If the string matches the regexp
              if (r.match(match))
              {
                  // Say that it matches
                  String out = "Matches.\n\n";
  
                  // Show contents of parenthesized subexpressions
                  for (int i = 0; i < r.getParenCount(); i++)
                  {
                      out += "$" + i + " = " + r.getParen(i) + "\n";
                  }
                  sayMatch(out);
              }
              else
              {
                  // Didn't match!
                  sayMatch("Does not match");
              }
          }
          catch (Throwable t)
          {
              sayMatch(throwableToString(t));
          }
      }
  
      /**
       * Called when text values change
       * @param e TextEvent
       */
      public void textValueChanged(TextEvent e)
      {
          // If it's a generic update or the regexp changed...
          if (e == null || e.getSource() == fieldRE)
          {
              // Update regexp
              updateRE(fieldRE.getText());
          }
  
          // We always need to update the match results
          updateMatch(fieldMatch.getText());
      }
  
      /**
       * Main application entrypoint.
       * @param arg Command line arguments
       */
      static public void main(String[] arg)
      {
          Frame f = new Frame("RE Demo");
          // f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          f.addWindowListener(new WindowAdapter()
          {
              public void windowClosing(WindowEvent e)
              {
                  System.exit(0);
              }
          });
          REDemo demo = new REDemo();
          f.add(demo);
          demo.init();
          f.pack();
          f.setVisible(true);
      }
  }
  