Aplicação Swing em Groovy para Regular Expressions

Hoje um usuário (Jeremy Rayner) da lista do Grails nos enviou uma pequena aplicação desktop escrita em Groovy que pode ser bastante útil para testar Regular Expressions. É tão pequena que vou colocar o código fonte abaixo. Esta aplicação faz o highlight das partes de um texto que você colocar de acordo com a expressão regular inserida. Veja screen shot abaixo. Para executar basta salvar este código num script RegexCoach.groovy e executar o comando: groovy RegexCoach

// Groovy Regex Coach - Copyright 2007 Jeremy Rayner
// inspired by http://weitz.de/regex-coach/
import java.awt.*
import java.awt.event.*
import java.util.regex.*
import javax.swing.*
import javax.swing.text.DefaultHighlighter
import groovy.swing.SwingBuilder

// define the view
def swing = new SwingBuilder()
def gui = swing.frame(title:'The Groovy Regex Coach', location:[20,40], size:[600,500], defaultCloseOperation:WindowConstants.EXIT_ON_CLOSE) {
  panel(layout:new BorderLayout()) {
    splitPane(orientation:JSplitPane.VERTICAL_SPLIT, dividerLocation:150) {
      panel(layout:new BorderLayout()) {
    label(constraints:BorderLayout.NORTH, text:'Regular expression:')
    scrollPane(constraints:BorderLayout.CENTER) {textPane(id:'regexPane')}
      }
      panel(layout:new BorderLayout()) {
    label(constraints:BorderLayout.NORTH, text:'Target string:')
    scrollPane(constraints:BorderLayout.CENTER) {textPane(id:'targetPane')}
    panel(constraints:BorderLayout.SOUTH, layout:new FlowLayout()) {
      button('<<-', id:'scanLeft')
      button('->>', id:'scanRight')
    }
      }
    }
  }
}
def highlighter = new RegexHighlighter(swing:swing)
swing.regexPane.addKeyListener(highlighter)
swing.targetPane.addKeyListener(highlighter)
swing.scanLeft.addActionListener(highlighter)
swing.scanRight.addActionListener(highlighter)
gui.show()

class RegexHighlighter extends KeyAdapter implements ActionListener {
  def swing // reference to the view
  int scanIndex // how many times to execute matcher.find()
  def orange = new DefaultHighlighter.DefaultHighlightPainter(Color.ORANGE)
  def yellow = new DefaultHighlighter.DefaultHighlightPainter(Color.YELLOW)
  def red = new DefaultHighlighter.DefaultHighlightPainter(Color.RED)

  // react to user actions
  public void actionPerformed(ActionEvent event) {
    if (event.actionCommand == '<<-') {scanIndex = Math.max(scanIndex - 1, 0)}
    if (event.actionCommand == '->>') {scanIndex++}
    doHighlights()
  }
  public void keyReleased(KeyEvent event) {
    scanIndex = 0
    doHighlights()
  }

  // the main regex logic
  private void doHighlights() {
    try {
      swing.regexPane.highlighter.removeAllHighlights()
      swing.targetPane.highlighter.removeAllHighlights()
      def regex = swing.regexPane.text
      def target = swing.targetPane.text
      def matcher = (target =~ regex) 
      int scan = 0
      while (scan < scanIndex) {
    matcher.find()
    scan++
      }
      if (matcher.find()) {
          int i = 0
    while (i++ < matcher.groupCount()) {
      swing.targetPane.highlighter.addHighlight(matcher.start(i), matcher.end(i), orange)
    }
    swing.targetPane.highlighter.addHighlight(matcher.start(), matcher.end(), yellow)
      } else {
    scanIndex = Math.max(scan - 1, 0)
    if (scanIndex > 0) {doHighlights()}
      }
    } catch (PatternSyntaxException e) {
      swing.regexPane.highlighter.addHighlight(e.index, e.index + 2, red)
    }
  }
}