/*
* 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.factory;
import java.util.Comparator;
import com.gs.collections.api.block.function.Function;
import com.gs.collections.api.block.function.Function2;
import com.gs.collections.impl.block.function.checked.CheckedFunction2;
import com.gs.collections.impl.block.function.checked.ThrowingFunction2;
/**
* Contains factory methods for creating {@link Function2} instances.
*/
public final class Functions2
{
private static final Function2<Integer, Integer, Integer> INTEGER_ADDITION = new IntegerAddition();
private Functions2()
{
throw new AssertionError("Suppress default constructor for noninstantiability");
}
public static <T, V, P> Function2<T, P, V> fromFunction(Function<? super T, ? extends V> function)
{
return new FunctionAdapter<T, P, V>(function);
}
public static <T, V, P> Function2<T, P, V> throwing(ThrowingFunction2<T, P, V> throwingFunction2)
{
return new ThrowingFunction2Adapter<T, P, V>(throwingFunction2);
}
public static Function2<Integer, Integer, Integer> integerAddition()
{
return INTEGER_ADDITION;
}
public static <T> Function2<T, T, T> min(Comparator<? super T> comparator)
{
return new MinFunction2<T>(comparator);
}
public static <T> Function2<T, T, T> max(Comparator<? super T> comparator)
{
return new MaxFunction2<T>(comparator);
}
public static <T, V extends Comparable<? super V>> Function2<T, T, T> minBy(Function<? super T, ? extends V> function)
{
return new MinByFunction2<T, V>(function);
}
public static <T, V extends Comparable<? super V>> Function2<T, T, T> maxBy(Function<? super T, ? extends V> function)
{
return new MaxByFunction2<T, V>(function);
}
private static final class FunctionAdapter<T, P, V> implements Function2<T, P, V>
{
private static final long serialVersionUID = 1L;
private final Function<? super T, ? extends V> function;
private FunctionAdapter(Function<? super T, ? extends V> function)
{
this.function = function;
}
public V value(T each, P parameter)
{
return this.function.valueOf(each);
}
}
private static class IntegerAddition implements Function2<Integer, Integer, Integer>
{
private static final long serialVersionUID = 1L;
public Integer value(Integer aggregate, Integer value)
{
return aggregate + value;
}
}
private static final class ThrowingFunction2Adapter<T, P, V> extends CheckedFunction2<T, P, V>
{
private static final long serialVersionUID = 1L;
private final ThrowingFunction2<T, P, V> throwingFunction2;
private ThrowingFunction2Adapter(ThrowingFunction2<T, P, V> throwingFunction2)
{
this.throwingFunction2 = throwingFunction2;
}
public V safeValue(T argument1, P argument2) throws Exception
{
return this.throwingFunction2.safeValue(argument1, argument2);
}
}
private static final class MinFunction2<T> implements Function2<T, T, T>
{
private static final long serialVersionUID = 1L;
private final Comparator<? super T> comparator;
private MinFunction2(Comparator<? super T> comparator)
{
this.comparator = comparator;
}
public T value(T argument1, T argument2)
{
return this.comparator.compare(argument1, argument2) > 0 ? argument2 : argument1;
}
}
private static final class MaxFunction2<T> implements Function2<T, T, T>
{
private static final long serialVersionUID = 1L;
private final Comparator<? super T> comparator;
private MaxFunction2(Comparator<? super T> comparator)
{
this.comparator = comparator;
}
public T value(T argument1, T argument2)
{
return this.comparator.compare(argument1, argument2) < 0 ? argument2 : argument1;
}
}
private static final class MinByFunction2<T, V extends Comparable<? super V>> implements Function2<T, T, T>
{
private static final long serialVersionUID = 1L;
private final Function<? super T, ? extends V> function;
private MinByFunction2(Function<? super T, ? extends V> function)
{
this.function = function;
}
public T value(T argument1, T argument2)
{
V first = this.function.valueOf(argument1);
V second = this.function.valueOf(argument2);
return first.compareTo(second) > 0 ? argument2 : argument1;
}
}
private static final class MaxByFunction2<T, V extends Comparable<? super V>> implements Function2<T, T, T>
{
private static final long serialVersionUID = 1L;
private final Function<? super T, ? extends V> function;
private MaxByFunction2(Function<? super T, ? extends V> function)
{
this.function = function;
}
public T value(T argument1, T argument2)
{
V first = this.function.valueOf(argument1);
V second = this.function.valueOf(argument2);
return first.compareTo(second) < 0 ? argument2 : argument1;
}
}
}