/*
* Copyright 2003-2007 the original author or authors.
*
* Licensed 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 groovy.util;
import groovy.lang.Closure;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.Iterator;
import java.util.List;
/**
* A helper class for sorting objects via a closure to return the field
* or operation on which to sort.
*
* @author <a href="mailto:james@coredevelopers.net">James Strachan</a>
* @version $Revision: 10259 $
*/
public class OrderBy implements Comparator {
private List closures;
public OrderBy() {
this.closures = new ArrayList();
}
public OrderBy(Closure closure) {
this();
closures.add(closure);
}
public OrderBy(List closures) {
this.closures = closures;
}
public void add(Closure closure) {
closures.add(closure);
}
public int compare(Object object1, Object object2) {
for (Iterator iter = closures.iterator(); iter.hasNext();) {
Closure closure = (Closure) iter.next();
Object value1 = closure.call(object1);
Object value2 = closure.call(object2);
if (value1 == value2) {
continue;
}
if (value1 == null) {
return -1;
}
if (value1 instanceof Comparable) {
Comparable c1 = (Comparable) value1;
int result = c1.compareTo(value2);
if (result == 0) {
continue;
} else {
return result;
}
}
if (value1.equals(value2)) {
continue;
}
return value1.hashCode() - value2.hashCode();
}
return 0;
}
}