net.sourceforge.phpeclipse.ui/src/net/sourceforge/phpdt/internal/ui/text/template/contentassist/InclusivePositionUpdater.java

   1 /*******************************************************************************
   2  * Copyright (c) 2000, 2004 IBM Corporation and others.
   3  * All rights reserved. This program and the accompanying materials
   4  * are made available under the terms of the Common Public License v1.0
   5  * which accompanies this distribution, and is available at
   6  * http://www.eclipse.org/legal/cpl-v10.html
   7  *
   8  * Contributors:
   9  *     IBM Corporation - initial API and implementation
  10  *******************************************************************************/
  11 package net.sourceforge.phpdt.internal.ui.text.template.contentassist;
  12
  13 import org.eclipse.jface.text.BadPositionCategoryException;
  14 import org.eclipse.jface.text.DocumentEvent;
  15 import org.eclipse.jface.text.IPositionUpdater;
  16 import org.eclipse.jface.text.Position;
  17
  18 /**
  19  * Position updater that takes any change in [position.offset, position.offset +
  20  * position.length] as belonging to the position.
  21  *
  22  * @since 3.0
  23  */
  24 class InclusivePositionUpdater implements IPositionUpdater {
  25
  26         /** The position category. */
  27         private final String fCategory;
  28
  29         /**
  30          * Creates a new updater for the given <code>category</code>.
  31          *
  32          * @param category
  33          *            the new category.
  34          */
  35         public InclusivePositionUpdater(String category) {
  36                 fCategory = category;
  37         }
  38
  39         /*
  40          * @see org.eclipse.jface.text.IPositionUpdater#update(org.eclipse.jface.text.DocumentEvent)
  41          */
  42         public void update(DocumentEvent event) {
  43
  44                 int eventOffset = event.getOffset();
  45                 int eventOldLength = event.getLength();
  46                 int eventNewLength = event.getText() == null ? 0 : event.getText()
  47                                 .length();
  48                 int deltaLength = eventNewLength - eventOldLength;
  49
  50                 try {
  51                         Position[] positions = event.getDocument().getPositions(fCategory);
  52
  53                         for (int i = 0; i != positions.length; i++) {
  54
  55                                 Position position = positions[i];
  56
  57                                 if (position.isDeleted())
  58                                         continue;
  59
  60                                 int offset = position.getOffset();
  61                                 int length = position.getLength();
  62                                 int end = offset + length;
  63
  64                                 if (offset > eventOffset + eventOldLength)
  65                                         // position comes way
  66                                         // after change - shift
  67                                         position.setOffset(offset + deltaLength);
  68                                 else if (end < eventOffset) {
  69                                         // position comes way before change -
  70                                         // leave alone
  71                                 } else if (offset <= eventOffset
  72                                                 && end >= eventOffset + eventOldLength) {
  73                                         // event completely internal to the position - adjust length
  74                                         position.setLength(length + deltaLength);
  75                                 } else if (offset < eventOffset) {
  76                                         // event extends over end of position - adjust length
  77                                         int newEnd = eventOffset + eventNewLength;
  78                                         position.setLength(newEnd - offset);
  79                                 } else if (end > eventOffset + eventOldLength) {
  80                                         // event extends from before position into it - adjust
  81                                         // offset
  82                                         // and length
  83                                         // offset becomes end of event, length ajusted acordingly
  84                                         // we want to recycle the overlapping part
  85                                         position.setOffset(eventOffset);
  86                                         int deleted = eventOffset + eventOldLength - offset;
  87                                         position.setLength(length - deleted + eventNewLength);
  88                                 } else {
  89                                         // event consumes the position - delete it
  90                                         position.delete();
  91                                 }
  92                         }
  93                 } catch (BadPositionCategoryException e) {
  94                         // ignore and return
  95                 }
  96         }
  97
  98         /**
  99          * Returns the position category.
 100          *
 101          * @return the position category
 102          */
 103         public String getCategory() {
 104                 return fCategory;
 105         }
 106
 107 }