/*
* Copyright 2014 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.function.Function;
import com.gs.collections.api.list.MutableList;
import com.gs.collections.impl.block.factory.Comparators;
import com.gs.collections.impl.list.mutable.FastList;
import org.junit.Assert;
import org.junit.Test;
public class FunctionComparatorTest
{
private static final Band VAN_HALEN = new Band("Van Halen");
private static final Band BON_JOVI = new Band("Bon Jovi");
private static final Band METALLICA = new Band("Metallica");
private static final Band SCORPIONS = new Band("Scorpions");
private static final Band ACDC = new Band("AC/DC");
private static final Band ZZTOP = new Band("ZZ Top");
@Test
public void comparator()
{
FunctionComparator<Band, String> comparator = new FunctionComparator<>(
Band.TO_NAME,
String::compareTo);
Assert.assertEquals(comparator.compare(ACDC, ZZTOP), ACDC.getName().compareTo(ZZTOP.getName()));
Assert.assertEquals(comparator.compare(ZZTOP, ACDC), ZZTOP.getName().compareTo(ACDC.getName()));
}
private MutableList<Band> createTestList()
{
return FastList.newListWith(VAN_HALEN, SCORPIONS, BON_JOVI, METALLICA);
}
@Test
public void functionComparatorBuiltTheHardWay()
{
Comparator<Band> byName = (bandA, bandB) -> Band.TO_NAME.valueOf(bandA).compareTo(Band.TO_NAME.valueOf(bandB));
MutableList<Band> sortedList = this.createTestList().sortThis(byName);
Assert.assertEquals(FastList.newListWith(BON_JOVI, METALLICA, SCORPIONS, VAN_HALEN), sortedList);
}
@Test
public void functionComparatorBuiltTheEasyWay()
{
Comparator<Band> byName = Comparators.byFunction(Band.TO_NAME, String::compareTo);
MutableList<Band> sortedList = this.createTestList().sortThis(byName);
Assert.assertEquals(FastList.newListWith(BON_JOVI, METALLICA, SCORPIONS, VAN_HALEN), sortedList);
}
private static final class Band
{
public static final Function<Band, String> TO_NAME = new Function<Band, String>()
{
public String valueOf(Band band)
{
return band.name;
}
};
private final String name;
private Band(String name)
{
this.name = name;
}
public String getName()
{
return this.name;
}
@Override
public String toString()
{
return this.name;
}
@Override
public boolean equals(Object other)
{
return this == other || other instanceof Band && this.name.equals(((Band) other).name);
}
@Override
public int hashCode()
{
return this.name.hashCode();
}
}
}