net.sourceforge.phpeclipse/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 + position.length] as
  20  * 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 the new category.
  33          */
  34         public InclusivePositionUpdater(String category) {
  35                 fCategory= category;
  36         }
  37
  38         /*
  39          * @see org.eclipse.jface.text.IPositionUpdater#update(org.eclipse.jface.text.DocumentEvent)
  40          */
  41         public void update(DocumentEvent event) {
  42
  43                 int eventOffset= event.getOffset();
  44                 int eventOldLength= event.getLength();
  45                 int eventNewLength= event.getText() == null ? 0 : event.getText().length();
  46                 int deltaLength= eventNewLength - eventOldLength;
  47
  48                 try {
  49                         Position[] positions= event.getDocument().getPositions(fCategory);
  50
  51                         for (int i= 0; i != positions.length; i++) {
  52
  53                                 Position position= positions[i];
  54
  55                                 if (position.isDeleted())
  56                                         continue;
  57
  58                                 int offset= position.getOffset();
  59                                 int length= position.getLength();
  60                                 int end= offset + length;
  61
  62                                 if (offset > eventOffset + eventOldLength)
  63                                         // position comes way
  64                                         // after change - shift
  65                                         position.setOffset(offset + deltaLength);
  66                                 else if (end < eventOffset) {
  67                                         // position comes way before change -
  68                                         // leave alone
  69                                 } else if (offset <= eventOffset && end >= eventOffset + eventOldLength) {
  70                                         // event completely internal to the position - adjust length
  71                                         position.setLength(length + deltaLength);
  72                                 } else if (offset < eventOffset) {
  73                                         // event extends over end of position - adjust length
  74                                         int newEnd= eventOffset + eventNewLength;
  75                                         position.setLength(newEnd - offset);
  76                                 } else if (end > eventOffset + eventOldLength) {
  77                                         // event extends from before position into it - adjust offset
  78                                         // and length
  79                                         // offset becomes end of event, length ajusted acordingly
  80                                         // we want to recycle the overlapping part
  81                                         position.setOffset(eventOffset);
  82                                         int deleted= eventOffset + eventOldLength - offset;
  83                                         position.setLength(length - deleted + eventNewLength);
  84                                 } else {
  85                                         // event consumes the position - delete it
  86                                         position.delete();
  87                                 }
  88                         }
  89                 } catch (BadPositionCategoryException e) {
  90                         // ignore and return
  91                 }
  92         }
  93
  94         /**
  95          * Returns the position category.
  96          *
  97          * @return the position category
  98          */
  99         public String getCategory() {
 100                 return fCategory;
 101         }
 102
 103 }