org.netbeans.swing.tabcontrol.event.ArrayDiff Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.netbeans.swing.tabcontrol.event;
import org.netbeans.swing.tabcontrol.TabData;
import java.util.*;
/*
* ArrayDiff.java
*
* Created on November 5, 2003, 12:44 PM
*/
/**
* Class representing a diff of two arrays. Note that it is
* not designed to work with arrays which contain the same
* element more than one time - in that case, the results are undefined.
* Note the current implementation is unoptimized and fairly brute force.
*
* @author Tim Boudreau
*/
public final class ArrayDiff {
/**
* The old array
*/
private TabData[] old;
/**
* The new array
*/
private TabData[] nue;
//XXX all of this could be implemented more efficiently with a single
//loop to calculate all statistics and so forth. The approach is algorithmically
//inelegant and brute force. To do that would significantly
//increase the complexity of the code, but it could be done later as an
//optimization
/**
* Creates a new instance of ArrayDiff
*/
private ArrayDiff(TabData[] old, TabData[] nue) {
this.old = old;
this.nue = nue;
if (nue == null || old == null) {
throw new NullPointerException(old == null && nue == null ?
"Both arrays are null" :
old == null ?
"Old array is null" :
"New array is null");
}
}
/**
* Get the array representing the old state
*/
public TabData[] getOldData() {
return old;
}
/**
* Get the array representing the new state
*/
public TabData[] getNewData() {
return nue;
}
/**
* Returns an ArrayDiff object if the two arrays are not the same, or null
* if they are
*/
public static ArrayDiff createDiff(TabData[] old, TabData[] nue) {
if (!Arrays.equals(old, nue)) {
return new ArrayDiff(old, nue);
} else {
return null;
}
}
private Set deleted = null;
/**
* Returns the indices of objects in the old array which are not present in
* the new array. The resulting array's size will be that of the old array
*/
public Set getDeletedIndices() {
if (deleted == null) {
HashSet set = new HashSet(Arrays.asList(nue));
HashSet results = new HashSet(old.length);
for (int i = 0; i < old.length; i++) {
if (!set.contains(old[i])) {
results.add(new Integer(i));
}
}
deleted = results;
}
return deleted;
}
private Set added = null;
/**
* Returns the indices of objects in the new array which are not present in
* the old array
*/
public Set getAddedIndices() {
if (added == null) {
HashSet set = new HashSet(Arrays.asList(old));
Set results = new HashSet(nue.length);
for (int i = 0; i < nue.length; i++) {
if (!set.contains(nue[i])) {
results.add(new Integer(i));
}
}
added = results;
}
return added;
}
/**
* Returns the indices of objects which differ in any way between the new
* and old array. The size of the result is Math.max(old.length,
* nue.length).
*/
public Set getChangedIndices() {
//XXX can add similar caching as with deleted/added fields if it looks
//to prove useful. getDeletedIndices() and getAddedIndices() are called
//more than once, and the computation can be expensive.
int max = Math.max(nue.length, old.length);
HashSet results = new HashSet(max);
for (int i = 0; i < max; i++) {
if (i < old.length && i < nue.length) {
if (!old[i].equals(nue[i])) {
results.add(new Integer(i));
}
} else {
results.add(new Integer(i));
}
}
return results;
}
/**
* Returns the indices of objects which were in the old array and are also
* in the new array, but at a different index. The indices returned are
* indices into the old array.
*/
public Set getMovedIndices() {
HashSet set = new HashSet(Arrays.asList(nue));
HashSet results = new HashSet(old.length);
for (int i = 0; i < old.length; i++) {
boolean isPresent = set.contains(old[i]);
if (isPresent) {
boolean isMoved = (i < nue.length
&& !nue[i].equals(old[i])) || i >= nue.length;
if (isMoved) {
results.add(new Integer(i));
}
}
}
return results;
}
public String toString() {
StringBuffer sb = new StringBuffer();
sb.append("");
return sb.toString();
}
private static String outCol(Collection c) {
Iterator i = c.iterator();
StringBuffer result = new StringBuffer();
while (i.hasNext()) {
Object o = i.next();
result.append(o.toString());
if (i.hasNext()) {
result.append(",");
}
}
return result.toString();
}
public boolean equals(Object o) {
if (o instanceof ArrayDiff) {
if (o == this) {
return true;
}
TabData[] otherOld = ((ArrayDiff) o).getOldData();
TabData[] otherNue = ((ArrayDiff) o).getNewData();
return Arrays.equals(old, otherOld)
&& Arrays.equals(nue, otherNue);
}
return false;
}
public int hashCode() {
return arrayHashCode(old) ^ arrayHashCode(nue);
}
private static int arrayHashCode(Object[] o) {
int result = 0;
for (int i = 0; i < o.length; i++) {
result += o[i].hashCode() ^ i;
}
return result;
}
}