/*
* Copyright 2003-2010 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 org.codehaus.groovy.runtime.NumberAwareComparator;
import org.codehaus.groovy.runtime.typehandling.DefaultTypeTransformation;
import java.util.ArrayList;
import java.util.Comparator;
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 $Revision$
*/
public class OrderBy<T> implements Comparator<T> {
private final List<Closure> closures;
private boolean equalityCheck;
private final NumberAwareComparator<Object> numberAwareComparator = new NumberAwareComparator<Object>();
public OrderBy() {
this.closures = new ArrayList<Closure>();
}
public OrderBy(Closure closure) {
this();
closures.add(closure);
}
public OrderBy(List<Closure> closures) {
this.closures = closures;
}
public void add(Closure closure) {
closures.add(closure);
}
public int compare(T object1, T object2) {
for (Closure closure : closures) {
Object value1 = closure.call(object1);
Object value2 = closure.call(object2);
int result;
if (!equalityCheck || (value1 instanceof Comparable && value2 instanceof Comparable)) {
result = numberAwareComparator.compare(value1, value2);
} else {
result = DefaultTypeTransformation.compareEqual(value1, value2) ? 0 : -1;
}
if (result == 0) continue;
return result;
}
return 0;
}
public boolean isEqualityCheck() {
return equalityCheck;
}
public void setEqualityCheck(boolean equalityCheck) {
this.equalityCheck = equalityCheck;
}
}