eu.etaxonomy.taxeditor.editor/src/main/java/eu/etaxonomy/taxeditor/editor/name/container/LineBreakListener.java

   1 /**
   2 * Copyright (C) 2007 EDIT
   3 * European Distributed Institute of Taxonomy
   4 * http://www.e-taxonomy.eu
   5 *
   6 * The contents of this file are subject to the Mozilla Public License Version 1.1
   7 * See LICENSE.TXT at the top of this package for the full license terms.
   8 */
   9
  10 package eu.etaxonomy.taxeditor.editor.name.container;
  11
  12 import java.util.ArrayList;
  13 import java.util.Collection;
  14 import java.util.Scanner;
  15
  16 import org.eclipse.swt.custom.StyledText;
  17 import org.eclipse.swt.events.VerifyEvent;
  18 import org.eclipse.swt.events.VerifyListener;
  19
  20 /**
  21  * Checks text entered into a StyledText widget for line breaks, sends
  22  * split text to abstract method handleSplitText().
  23  *  <p>
  24  * VerifyListener interface methods break up the text into lines. Each line is sent individually
  25  * to the handleSplitText() method when the KeyListener interface method keyReleased() is called.
  26  * This is because if the StyledText widget is disposed before the key is released, an SWT
  27  * exception occurs.
  28  * <p>
  29  * The listener should be set on the StyledText widget as follows:
  30  * <code><pre>
  31  *              StyledText styledText = new SourceViewer().getTextWidget();
  32  *              LineBreakListener lineBreakListener = new LineBreakListener() {
  33  *                      public void handleSplitText(String text) {
  34  *                              ... some operation ...
  35  *                      }
  36  *              };
  37  *
  38  *              styledText.addVerifyListener(lineBreakListener);
  39  *              styledText.addKeyListener(lineBreakListener);
  40  * </pre></code>
  41  *
  42  * @author p.ciardelli
  43  * @created 19.05.2008
  44  * @version 1.0
  45  */
  46 public abstract class LineBreakListener implements VerifyListener{
  47
  48         private static String LINE_BREAK = System.getProperty("line.separator");
  49
  50
  51         /**
  52          * {@inheritDoc}
  53          *
  54          * Checks for 3 conditions of name viewer text:
  55          *   1) no line breaks in text
  56          *   2) line break at the end of the text
  57          *   3) line break in the middle of the text
  58          * @see org.eclipse.swt.events.VerifyListener#verifyText(org.eclipse.swt.events.VerifyEvent)
  59          */
  60         public void verifyText(VerifyEvent e) {
  61
  62                 String verifyText = e.text;
  63
  64                 StyledText styledText = (StyledText) e.widget;
  65                 String widgetText = styledText.getText();
  66                 int cursorPosition = styledText.getCaretOffset();
  67
  68                 // If no line break in verifyText, Parse text normally
  69                 if (!verifyText.contains(LINE_BREAK)) {
  70                         return;
  71                 }
  72
  73                 // Don't add verifyText without further processing
  74                 e.doit = false;
  75
  76                 // If user has entered return at the end of the line,
  77                 //  make a new, empty synonym
  78                 if (widgetText.length() == cursorPosition &&
  79                                 verifyText.equals(LINE_BREAK)) {
  80                         handleSplitText("");
  81                         return;
  82                 }
  83
  84                 // Concatenate old and new texts
  85                 String textForSplitting = widgetText.substring(0, cursorPosition)
  86                                 + verifyText
  87                                 + widgetText.substring(cursorPosition);
  88
  89                 // Split on line breaks
  90                 Scanner scanner = new Scanner( textForSplitting );
  91                 scanner.useDelimiter(LINE_BREAK);
  92
  93                 // Put first string into name viewer
  94                 styledText.setText(scanner.next());
  95
  96                 // Start new synonyms with the rest
  97                 while (scanner.hasNext()) {
  98                         handleSplitText(scanner.next());
  99                 }
 100         }
 101
 102         /**
 103          * <p>handleSplitText</p>
 104          *
 105          * @param text a {@link java.lang.String} object.
 106          */
 107         abstract public void handleSplitText(String text);
 108 }