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Viewing changes to TuxGuitar/src/org/herac/tuxguitar/gui/undo/UndoableManager.java

  • Committer: Bazaar Package Importer
  • Author(s): Philippe Coval
  • Date: 2008-06-19 00:30:30 UTC
  • mto: (5.1.2 sid)
  • mto: This revision was merged to the branch mainline in revision 3.
  • Revision ID: james.westby@ubuntu.com-20080619003030-h719szrhsngou7c6
Tags: upstream-1.0
Import upstream version 1.0

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TuxGuitar/src/org/herac/tuxguitar/gui/undo/UndoableManager.java
 
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/*
 
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 * Created on 08-ago-2005
 
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 *
 
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 * TODO To change the template for this generated file go to
 
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 * Window - Preferences - Java - Code Style - Code Templates
 
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 */
 
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package org.herac.tuxguitar.gui.undo;
 
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import java.util.ArrayList;
 
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import java.util.List;
 
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/**
 
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 * @author julian
 
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 * 
 
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 * TODO To change the template for this generated type comment go to Window - Preferences - Java - Code Style - Code Templates
 
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 */
 
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public class UndoableManager {
 
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        private static final int LIMIT = 100;
 
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        private int indexOfNextAdd;
 
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        private List edits;
 
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        public UndoableManager() {
 
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                this.init();
 
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        }
 
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        public void discardAllEdits() {
 
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                this.reset();
 
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        }
 
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        public synchronized void undo() throws CannotUndoException {
 
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                UndoableEdit edit = editToBeUndone();
 
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                if (edit == null) {
 
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                        throw new CannotUndoException();
 
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                }
 
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                try{
 
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                        edit.undo();
 
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                }catch(Throwable throwable){
 
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                        throw new CannotUndoException(throwable);
 
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                }
 
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                this.indexOfNextAdd--;
 
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        }
 
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        public synchronized void redo() throws CannotRedoException {
 
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                UndoableEdit edit = editToBeRedone();
 
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                if (edit == null) {
 
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                        throw new CannotRedoException();
 
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                }
 
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                try{
 
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                        edit.redo();
 
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                }catch(Throwable throwable){
 
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                        throw new CannotRedoException();
 
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                }
 
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                this.indexOfNextAdd++;
 
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        }
 
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        public synchronized boolean canUndo() {
 
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                boolean canUndo = false;
 
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                UndoableEdit edit = editToBeUndone();
 
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                if (edit != null) {
 
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                        canUndo = edit.canUndo();
 
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                }
 
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                return canUndo;
 
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        }
 
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        public synchronized boolean canRedo() {
 
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                boolean canRedo = false;
 
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                UndoableEdit edit = editToBeRedone();
 
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                if (edit != null) {
 
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                        canRedo = edit.canRedo();
 
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                }
 
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                return canRedo;
 
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        }
 
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        public synchronized void addEdit(UndoableEdit anEdit) {
 
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                checkForUnused();
 
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                checkForLimit();
 
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                this.edits.add(this.indexOfNextAdd, anEdit);
 
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                this.indexOfNextAdd++;
 
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        }
 
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        private void checkForUnused() {
 
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                while (this.edits.size() > this.indexOfNextAdd) {
 
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                        UndoableEdit edit = (UndoableEdit) this.edits.get(this.indexOfNextAdd);
 
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                        remove(edit);
 
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                }
 
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        }
 
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        private void checkForLimit() {
 
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                while (this.edits.size() >= LIMIT) {
 
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                        UndoableEdit edit = (UndoableEdit) this.edits.get(0);
 
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                        remove(edit);
 
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                        this.indexOfNextAdd--;
 
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                }
 
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        }
 
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        private void remove(UndoableEdit edit) {
 
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                this.edits.remove(edit);
 
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        }
 
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        private UndoableEdit editToBeUndone() {
 
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                int index = this.indexOfNextAdd - 1;
 
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                if (index >= 0 && index < this.edits.size()) {
 
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                        return (UndoableEdit) this.edits.get(index);
 
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                }
 
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                return null;
 
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        }
 
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        private UndoableEdit editToBeRedone() {
 
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                int index = this.indexOfNextAdd;
 
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                if (index >= 0 && index < this.edits.size()) {
 
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                        return (UndoableEdit) this.edits.get(index);
 
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                }
 
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                return null;
 
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        }
 
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        private void init() {
 
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                this.indexOfNextAdd = 0;
 
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                this.edits = new ArrayList();
 
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        }
 
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        private void reset() {
 
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                this.indexOfNextAdd = 0;
 
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                this.edits.clear();
 
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        }
 
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}