| /******************************************************************************* |
| * Copyright (c) 2000, 2003 IBM Corporation and others. |
| * All rights reserved. This program and the accompanying materials |
| * are made available under the terms of the Common Public License v1.0 |
| * which accompanies this distribution, and is available at |
| * http://www.eclipse.org/legal/cpl-v10.html |
| * |
| * Contributors: |
| * IBM Corporation - initial API and implementation |
| *******************************************************************************/ |
| |
| package org.eclipse.jface.text; |
| |
| |
| /** |
| * Default implementation of <code>IPositionUpdater</code>. |
| * A default position updater must be configured with the position category |
| * whose positions it will update. Other position categories are not affected |
| * by this updater.<p> |
| * This implementation follows the following specification: |
| * <ul> |
| * <li> Inserting or deleting text before the position shifts the position accordingly. |
| * <li> Inserting text at the position offset shifts the position accordingly. |
| * <li> Inserting or deleting text completely surrounded by the position shrinks or stretches the position. |
| * <li> Inserting or deleting text after a position does not affect the position. |
| * <li> Deleting text which completly contains the position deletes the position. |
| * <li> Replacing text overlapping with the position considered as a sequence of first |
| * deleting the replaced text and afterwards inserting the new text. Thus, a |
| * position might first be shifted and shrink and then be stretched. |
| * </ul> |
| * This class can be used as is or be adapted by subclasses. Fields are protected to |
| * allow subclasses direct access. Because of the frequency with which position updaters |
| * are used this is a performance decision. |
| */ |
| public class DefaultPositionUpdater implements IPositionUpdater { |
| |
| /** The position category the updater draws responsible for */ |
| private String fCategory; |
| |
| /** Caches the currently investigated position */ |
| protected Position fPosition; |
| /** |
| * Remembers the original state of the investigated position |
| * @since 2.1 |
| */ |
| protected Position fOriginalPosition= new Position(0, 0); |
| /** Caches the offset of the replaced text */ |
| protected int fOffset; |
| /** Caches the length of the replaced text */ |
| protected int fLength; |
| /** Caches the length of the newly inserted text */ |
| protected int fReplaceLength; |
| /** Catches the document */ |
| protected IDocument fDocument; |
| |
| |
| /** |
| * Creates a new default positon updater for the given category. |
| * |
| * @param category the category the updater is responsible for |
| */ |
| public DefaultPositionUpdater(String category) { |
| fCategory= category; |
| } |
| |
| /** |
| * Returns the category this updater is resonsible for. |
| * |
| * @return the category this updater is resonsible for |
| */ |
| protected String getCategory() { |
| return fCategory; |
| } |
| |
| /** |
| * Adapts the currently investigated position to an insertion. |
| */ |
| protected void adaptToInsert() { |
| |
| int myStart= fPosition.offset; |
| int myEnd= fPosition.offset + fPosition.length -1; |
| myEnd= Math.max(myStart, myEnd); |
| |
| int yoursStart= fOffset; |
| int yoursEnd= fOffset + fReplaceLength -1; |
| yoursEnd= Math.max(yoursStart, yoursEnd); |
| |
| if (myEnd < yoursStart) |
| return; |
| |
| if (fLength <= 0) { |
| |
| if (myStart < yoursStart) |
| fPosition.length += fReplaceLength; |
| else |
| fPosition.offset += fReplaceLength; |
| |
| } else { |
| |
| if (myStart <= yoursStart && fOriginalPosition.offset <= yoursStart) |
| fPosition.length += fReplaceLength; |
| else |
| fPosition.offset += fReplaceLength; |
| } |
| } |
| |
| /** |
| * Adapts the currently investigated position to a deletion. |
| */ |
| protected void adaptToRemove() { |
| |
| int myStart= fPosition.offset; |
| int myEnd= fPosition.offset + fPosition.length -1; |
| myEnd= Math.max(myStart, myEnd); |
| |
| int yoursStart= fOffset; |
| int yoursEnd= fOffset + fLength -1; |
| yoursEnd= Math.max(yoursStart, yoursEnd); |
| |
| if (myEnd < yoursStart) |
| return; |
| |
| if (myStart <= yoursStart) { |
| |
| if (yoursEnd <= myEnd) |
| fPosition.length -= fLength; |
| else |
| fPosition.length -= (myEnd - yoursStart +1); |
| |
| } else if (yoursStart < myStart) { |
| |
| if (yoursEnd < myStart) |
| fPosition.offset -= fLength; |
| else { |
| fPosition.offset -= (myStart - yoursStart); |
| fPosition.length -= (yoursEnd - myStart +1); |
| } |
| |
| } |
| |
| // validate position to allowed values |
| if (fPosition.offset < 0) |
| fPosition.offset= 0; |
| |
| if (fPosition.length < 0) |
| fPosition.length= 0; |
| } |
| |
| /** |
| * Adapts the currently investigated position to the replace operation. |
| * First it checks whether the change replaces the whole range of the position. |
| * If not, it performs first the deletion of the previous text and afterwards |
| * the insertion of the new text. |
| */ |
| protected void adaptToReplace() { |
| |
| if (fPosition.offset == fOffset && fPosition.length == fLength && fPosition.length > 0) { |
| |
| // replace the whole range of the position |
| fPosition.length += (fReplaceLength - fLength); |
| if (fPosition.length < 0) { |
| fPosition.offset += fPosition.length; |
| fPosition.length= 0; |
| } |
| |
| } else { |
| |
| if (fLength > 0) |
| adaptToRemove(); |
| |
| if (fReplaceLength > 0) |
| adaptToInsert(); |
| } |
| } |
| |
| /** |
| * Determines whether the currently investigated position has been deleted by |
| * the replace operation specified in the current event. If so, it deletes |
| * the position and removes it from the document's position category. |
| * |
| * @return <code>true</code> if position has been deleted |
| */ |
| protected boolean notDeleted() { |
| |
| if (fOffset < fPosition.offset && (fPosition.offset + fPosition.length < fOffset + fLength)) { |
| |
| fPosition.delete(); |
| |
| try { |
| fDocument.removePosition(fCategory, fPosition); |
| } catch (BadPositionCategoryException x) { |
| } |
| |
| return false; |
| } |
| |
| return true; |
| } |
| |
| /* |
| * @see IPositionUpdater#update(DocumentEvent event) |
| */ |
| public void update(DocumentEvent event) { |
| |
| try { |
| |
| |
| fOffset= event.getOffset(); |
| fLength= event.getLength(); |
| fReplaceLength= (event.getText() == null ? 0 : event.getText().length()); |
| fDocument= event.getDocument(); |
| |
| Position[] category= fDocument.getPositions(fCategory); |
| for (int i= 0; i < category.length; i++) { |
| |
| fPosition= category[i]; |
| fOriginalPosition.offset= fPosition.offset; |
| fOriginalPosition.length= fPosition.length; |
| |
| if (notDeleted()) |
| adaptToReplace(); |
| } |
| |
| } catch (BadPositionCategoryException x) { |
| // do nothing |
| } |
| } |
| } |