| /******************************************************************************* |
| * 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 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.link; |
| |
| import java.util.ArrayList; |
| import java.util.Collections; |
| import java.util.Comparator; |
| import java.util.Iterator; |
| import java.util.List; |
| import java.util.NoSuchElementException; |
| |
| import org.eclipse.jface.text.Assert; |
| import org.eclipse.jface.text.Position; |
| import org.eclipse.jface.text.link.LinkedPosition; |
| |
| |
| |
| /** |
| * Iterator that leaps over the double occurrence of an element when switching from forward |
| * to backward iteration that is shown by <code>ListIterator</code>. |
| * |
| * @since 3.0 |
| */ |
| class TabStopIterator { |
| /** |
| * Comparator for <code>LinkedPosition</code>s. If the sequence nr. of two positions is equal, the |
| * offset is used. |
| */ |
| private static class SequenceComparator implements Comparator { |
| |
| /** |
| * {@inheritDoc} |
| * |
| * <p><code>o1</code> and <code>o2</code> are required to be instances |
| * of <code>LinkedPosition</code>.</p> |
| */ |
| public int compare(Object o1, Object o2) { |
| LinkedPosition p1= (LinkedPosition)o1; |
| LinkedPosition p2= (LinkedPosition)o2; |
| int i= p1.getSequenceNumber() - p2.getSequenceNumber(); |
| if (i != 0) |
| return i; |
| else |
| return p1.getOffset() - p2.getOffset(); |
| } |
| |
| } |
| |
| /** The comparator to sort the list of positions. */ |
| private static final Comparator fComparator= new SequenceComparator(); |
| |
| /** The iteration sequence. */ |
| private final ArrayList fList; |
| /** The size of <code>fList</code>. */ |
| private int fSize; |
| /** Index of the current element, to the first one initially. */ |
| private int fIndex; |
| /** Cycling property. */ |
| private boolean fIsCycling= false; |
| |
| TabStopIterator(List positionSequence) { |
| Assert.isNotNull(positionSequence); |
| fList= new ArrayList(positionSequence); |
| Collections.sort(fList, fComparator); |
| fSize= fList.size(); |
| fIndex= -1; |
| Assert.isTrue(fSize > 0); |
| } |
| |
| boolean hasNext(LinkedPosition current) { |
| return getNextIndex(current) != fSize; |
| } |
| |
| private int getNextIndex(LinkedPosition current) { |
| if (current != null && fList.get(fIndex) != current) |
| return findNext(current); |
| else if (fIsCycling && fIndex == fSize - 1) |
| return 0; |
| else |
| // default: increase |
| return fIndex + 1; |
| } |
| |
| /** |
| * Finds the closest position in the iteration set that follows after |
| * <code>current</code> and sets <code>fIndex</code> accordingly. If <code>current</code> |
| * is in the iteration set, the next in turn is chosen. |
| * |
| * @param current the current position |
| * @return <code>true</code> if there is a next position, <code>false</code> otherwise |
| */ |
| private int findNext(LinkedPosition current) { |
| Assert.isNotNull(current); |
| // if the position is in the iteration set, jump to the next one |
| int index= fList.indexOf(current); |
| if (index != -1) { |
| if (fIsCycling && index == fSize - 1) |
| return 0; |
| else |
| return index + 1; |
| } else { |
| // find the position that follows closest to the current position |
| LinkedPosition found= null; |
| for (Iterator it= fList.iterator(); it.hasNext(); ) { |
| LinkedPosition p= (LinkedPosition) it.next(); |
| if (p.offset > current.offset) |
| if (found == null || found.offset > p.offset) |
| found= p; |
| } |
| if (found != null) { |
| return fList.indexOf(found); |
| } else if (fIsCycling) { |
| return 0; |
| } else |
| return fSize; |
| } |
| } |
| |
| boolean hasPrevious(LinkedPosition current) { |
| return getPreviousIndex(current) != -1; |
| } |
| |
| private int getPreviousIndex(LinkedPosition current) { |
| if (current != null && fList.get(fIndex) != current) |
| return findPrevious(current); |
| else if (fIsCycling && fIndex == 0) |
| return fSize - 1; |
| else |
| return fIndex - 1; |
| } |
| |
| /** |
| * Finds the closest position in the iteration set that precedes |
| * <code>current</code>. If <code>current</code> |
| * is in the iteration set, the previous in turn is chosen. |
| * |
| * @param current the current position |
| * @return the index of the previous position |
| */ |
| private int findPrevious(LinkedPosition current) { |
| Assert.isNotNull(current); |
| // if the position is in the iteration set, jump to the next one |
| int index= fList.indexOf(current); |
| if (index != -1) { |
| if (fIsCycling && index == 0) |
| return fSize - 1; |
| else |
| return index - 1; |
| } else { |
| // find the position that follows closest to the current position |
| LinkedPosition found= null; |
| for (Iterator it= fList.iterator(); it.hasNext(); ) { |
| LinkedPosition p= (LinkedPosition) it.next(); |
| if (p.offset < current.offset) |
| if (found == null || found.offset < p.offset) |
| found= p; |
| } |
| if (found != null) { |
| return fList.indexOf(found); |
| } else if (fIsCycling) { |
| return fSize - 1; |
| } else |
| return -1; |
| } |
| } |
| |
| LinkedPosition next(LinkedPosition current) { |
| if (!hasNext(current)) |
| throw new NoSuchElementException(); |
| else |
| return (LinkedPosition) fList.get(fIndex= getNextIndex(current)); |
| } |
| |
| LinkedPosition previous(LinkedPosition current) { |
| if (!hasPrevious(current)) |
| throw new NoSuchElementException(); |
| else |
| return (LinkedPosition) fList.get(fIndex= getPreviousIndex(current)); |
| } |
| |
| void setCycling(boolean mode) { |
| fIsCycling= mode; |
| } |
| |
| void addPosition(Position position) { |
| fList.add(fSize++, position); |
| Collections.sort(fList, fComparator); |
| } |
| |
| void removePosition(Position position) { |
| if (fList.remove(position)) |
| fSize--; |
| } |
| |
| /** |
| * @return Returns the isCycling. |
| */ |
| boolean isCycling() { |
| return fIsCycling; |
| } |
| |
| LinkedPosition[] getPositions() { |
| return (LinkedPosition[]) fList.toArray(new LinkedPosition[0]); |
| } |
| } |