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/*
 * 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 io.microsphere.lang.function;

import java.util.function.Predicate;

/**
 * The utilities class for Java {@link Predicate}
 *
 * @since 1.0.0
 */
public interface Predicates {

    Predicate[] EMPTY_PREDICATE_ARRAY = new Predicate[0];


    static  Predicate[] emptyArray() {
        return (Predicate[]) EMPTY_PREDICATE_ARRAY;
    }

    /**
     * {@link Predicate} always return true
     *
     * @param  the type to test
     * @return true
     */
    static  Predicate alwaysTrue() {
        return e -> true;
    }

    /**
     * {@link Predicate} always return false
     *
     * @param  the type to test
     * @return false
     */
    static  Predicate alwaysFalse() {
        return e -> false;
    }

    /**
     * a composed predicate that represents a short-circuiting logical AND of {@link Predicate predicates}
     *
     * @param predicates {@link Predicate predicates}
     * @param         the type to test
     * @return non-null
     */
    static  Predicate and(Predicate... predicates) {
        int length = predicates == null ? 0 : predicates.length;
        if (length == 0) {
            return alwaysTrue();
        } else if (length == 1) {
            return predicates[0];
        } else {
            Predicate andPredicate = alwaysTrue();
            for (Predicate p : predicates) {
                andPredicate = andPredicate.and(p);
            }
            return andPredicate;
        }
    }

    /**
     * a composed predicate that represents a short-circuiting logical OR of {@link Predicate predicates}
     *
     * @param predicates {@link Predicate predicates}
     * @param         the detected type
     * @return non-null
     */
    static  Predicate or(Predicate... predicates) {
        int length = predicates == null ? 0 : predicates.length;
        if (length == 0) {
            return alwaysTrue();
        } else if (length == 1) {
            return predicates[0];
        } else {
            Predicate orPredicate = alwaysFalse();
            for (Predicate p : predicates) {
                orPredicate = orPredicate.or(p);
            }
            return orPredicate;
        }
    }

}