001/*-
002 * Copyright 2015, 2016 Diamond Light Source Ltd.
003 *
004 * All rights reserved. This program and the accompanying materials
005 * are made available under the terms of the Eclipse Public License v1.0
006 * which accompanies this distribution, and is available at
007 * http://www.eclipse.org/legal/epl-v10.html
008 */
009
010package org.eclipse.january.dataset;
011
012import java.util.Arrays;
013
014/**
015 * Checks whether shape has changed between waits. Useful for where datasets are being extended.
016 * Note, {@link LazyDynamicDataset} already alerts its listeners when its shape is resized
017 */
018public class ShapeChangeChecker implements IDatasetChangeChecker {
019        
020        private ILazyDataset lazy;
021        private int[] shape;
022
023        @Override
024        public void setDataset(ILazyDataset dataset) {
025                if (dataset == null) {
026                        throw new IllegalArgumentException("Dataset must not be null");
027                }
028                lazy = dataset;
029                shape = lazy.getShape();
030        }
031
032        @Override
033        public boolean check() {
034                int[] cshape = lazy.getShape();
035                if (Arrays.equals(shape, cshape)) {
036                        return false;
037                }
038                shape = cshape;
039                return true;
040        }
041}