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