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.KeyListener;
  18 import org.eclipse.swt.events.VerifyEvent;
  19 import org.eclipse.swt.events.VerifyListener;
  20
  21 /**
  22  * Checks text entered into a StyledText widget for line breaks, sends
  23  * split text to abstract method handleSplitText().
  24  *  <p>
  25  * VerifyListener interface methods break up the text into lines. Each line is sent individually
  26  * to the handleSplitText() method when the KeyListener interface method keyReleased() is called.
  27  * This is because if the StyledText widget is disposed before the key is released, an SWT
  28  * exception occurs.
  29  * <p>
  30  * The listener should be set on the StyledText widget as follows:
  31  * <code><pre>
  32  *              StyledText styledText = new SourceViewer().getTextWidget();
  33  *              LineBreakListener lineBreakListener = new LineBreakListener() {
  34  *                      public void handleSplitText(String text) {
  35  *                              ... some operation ...
  36  *                      }
  37  *              };
  38  *
  39  *              styledText.addVerifyListener(lineBreakListener);
  40  *              styledText.addKeyListener(lineBreakListener);
  41  * </pre></code>
  42  *
  43  * @author p.ciardelli
  44  * @created 19.05.2008
  45  * @version 1.0
  46  */
  47
  48 public abstract class LineBreakListener implements VerifyListener{
  49
  50
  51         private static String LINE_BREAK = System.getProperty("line.separator"); //$NON-NLS-1$
  52
  53
  54         /**
  55          * {@inheritDoc}
  56          *
  57          * Checks for 3 conditions of name viewer text:
  58          *   1) no line breaks in text
  59          *   2) line break at the end of the text
  60          *   3) line break in the middle of the text
  61          * @see org.eclipse.swt.events.VerifyListener#verifyText(org.eclipse.swt.events.VerifyEvent)
  62          */
  63         public void verifyText(VerifyEvent e) {
  64
  65                 String verifyText = e.text;
  66
  67                 StyledText styledText = (StyledText) e.widget;
  68                 String widgetText = styledText.getText();
  69                 int cursorPosition = styledText.getCaretOffset();
  70
  71                 // If no line break in verifyText, Parse text normally
  72                 if (!verifyText.contains(LINE_BREAK)) {
  73                         return;
  74                 }
  75
  76                 // Don't add verifyText without further processing
  77                 e.doit = false;
  78
  79                 // If user has entered return at the end of the line,
  80                 //  make a new, empty synonym
  81                 if (widgetText.length() == cursorPosition &&
  82                                 verifyText.equals(LINE_BREAK)) {
  83                         handleSplitText(""); //$NON-NLS-1$
  84                         return;
  85                 }
  86
  87                 // Concatenate old and new texts
  88                 String textForSplitting = widgetText.substring(0, cursorPosition)
  89                                 + verifyText
  90                                 + widgetText.substring(cursorPosition);
  91
  92                 // Split on line breaks
  93                 Scanner scanner = new Scanner( textForSplitting );
  94                 scanner.useDelimiter(LINE_BREAK);
  95
  96                 // Put first string into name viewer
  97                 styledText.setText(scanner.next());
  98
  99                 // Start new synonyms with the rest
 100                 while (scanner.hasNext()) {
 101                         handleSplitText(scanner.next());
 102                 }
 103         }
 104
 105         /**
 106          * <p>handleSplitText</p>
 107          *
 108          * @param text a {@link java.lang.String} object.
 109          */
 110         abstract public void handleSplitText(String text);
 111 }