/**
*
* Copyright (c) 2006-2017, Speedment, Inc. All Rights Reserved.
*
* 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.speedment.common.combinatorics;
import com.speedment.common.combinatorics.internal.CombinationUtil;
import java.util.*;
import java.util.stream.Stream;
/**
* General Combination support. The class eagerly calculates all combinations.
*
* @author Per Minborg
*/
public final class Combination {
/**
* Creates and returns all possible combinations of the given elements.
*
* The order of the combinations in the stream is unspecified.
*
* @param <T> element type
* @param items to combine
* @return all possible combinations of the given elements
*/
@SafeVarargs
@SuppressWarnings("varargs") // Creating a List from an array is safe
public static <T> Stream<List<T>> of(final T... items) {
return CombinationUtil.of(items);
}
/**
* Creates and returns all possible combinations of the given elements
* whereby each element only occurs at most once in any given List. Elements
* are checked for occurrence by its {@code equals() } method.
*
* The order of the combinations in the stream is unspecified.
*
* @param <T> element type
* @param items to combine
* @return all possible combinations of the given elements whereby each
* element only occurs at most once in any given List
*/
@SafeVarargs
@SuppressWarnings("varargs") // Creating a List from an array is safe
public static <T> Stream<List<T>> ofDistinct(final T... items) {
return CombinationUtil.ofDistinct(items);
}
private Combination() {
throw new UnsupportedOperationException();
}
}