/*

 * Licensed to the Apache Software Foundation (ASF) under one or more

 * contributor license agreements.  See the NOTICE file distributed with

 * this work for additional information regarding copyright ownership.

 * The ASF licenses this file to You 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 org.apache.commons.collections4.functors;

import java.util.Collection;

import org.apache.commons.collections4.Predicate;

/**

 * Predicate implementation that returns true if only one of the

 * predicates return true.

 * If the array of predicates is empty, then this predicate returns false.

 * <p>

 * NOTE: In versions prior to 3.2 an array size of zero or one

 * threw an exception.

 * </p>

 *

 * @since 3.0

 */

public final class OnePredicate<T> extends AbstractQuantifierPredicate<T> {

    /** Serial version UID */

    private static final long serialVersionUID = -8125389089924745785L;

    /**

     * Factory to create the predicate.

     * <p>

     * If the array is size zero, the predicate always returns false.

     * If the array is size one, then that predicate is returned.

     *

     * @param <T> the type that the predicate queries

     * @param predicates  the predicates to check, cloned, not null

     * @return the <code>any</code> predicate

     * @throws NullPointerException if the predicates array is null

     * @throws NullPointerException if any predicate in the array is null

     */

    @SuppressWarnings("unchecked")

    public static <T> Predicate<T> onePredicate(final Predicate<? super T>... predicates) {

        FunctorUtils.validate(predicates);

        if (predicates.length == 0) {

            return FalsePredicate.<T>falsePredicate();

        }

        if (predicates.length == 1) {

            return (Predicate<T>) predicates[0];

        }

        return new OnePredicate<>(FunctorUtils.copy(predicates));

    }

    /**

     * Factory to create the predicate.

     *

     * @param <T> the type that the predicate queries

     * @param predicates  the predicates to check, cloned, not null

     * @return the <code>one</code> predicate

     * @throws NullPointerException if the predicates array is null

     * @throws NullPointerException if any predicate in the array is null

     */

    public static <T> Predicate<T> onePredicate(final Collection<? extends Predicate<? super T>> predicates) {

        final Predicate<? super T>[] preds = FunctorUtils.validate(predicates);

        return new OnePredicate<>(preds);

    }

    /**

     * Constructor that performs no validation.

     * Use <code>onePredicate</code> if you want that.

     *

     * @param predicates  the predicates to check, not cloned, not null

     */

    public OnePredicate(final Predicate<? super T>... predicates) {

        super(predicates);

    }

    /**

     * Evaluates the predicate returning true if only one decorated predicate

     * returns true.

     *

     * @param object  the input object

     * @return true if only one decorated predicate returns true

     */

    @Override

    public boolean evaluate(final T object) {

        boolean match = false;

        for (final Predicate<? super T> iPredicate : iPredicates) {

            if (iPredicate.evaluate(object)) {

                if (match) {

                    return false;

                }

                match = true;

            }

        }

        return match;

    }

}