/*
* Copyright 2011 Goldman Sachs.
*
* 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 com.gs.collections.impl.block.comparator;
import java.util.Comparator;
import com.gs.collections.api.block.SerializableComparator;
import com.gs.collections.api.block.function.Function;
/**
* Simple {@link Comparator} that uses a {@link Function}
* to select a value from the underlying object and compare it against a known value to determine ordering.
*/
public class FunctionComparator<T, V>
implements SerializableComparator<T>
{
private static final long serialVersionUID = 1L;
private final Function<? super T, ? extends V> function;
private final Comparator<V> comparator;
public FunctionComparator(Function<? super T, ? extends V> function, Comparator<V> comparator)
{
this.function = function;
this.comparator = comparator;
}
public int compare(T o1, T o2)
{
V attrValue1 = this.function.valueOf(o1);
V attrValue2 = this.function.valueOf(o2);
return this.comparator.compare(attrValue1, attrValue2);
}
}