/*

 * 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.io.Serializable;

import org.apache.commons.collections4.Equator;

import org.apache.commons.collections4.Predicate;

/**

 * Predicate implementation that returns true if the input is the same object

 * as the one stored in this predicate by equals.

 *

 * @since 3.0

 */

public final class EqualPredicate<T> implements Predicate<T>, Serializable {

    /** Serial version UID */

    private static final long serialVersionUID = 5633766978029907089L;

    /** The value to compare to */

    private final T iValue;

    /** The equator to use for comparison */

    private final Equator<T> equator;

    /**

     * Factory to create the predicate.

     *

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

     * @param object  the object to compare to

     * @return the predicate

     */

    public static <T> Predicate<T> equalPredicate(final T object) {

        if (object == null) {

            return NullPredicate.nullPredicate();

        }

        return new EqualPredicate<>(object);

    }

    /**

     * Factory to create the identity predicate.

     *

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

     * @param object  the object to compare to

     * @param equator  the equator to use for comparison

     * @return the predicate

     * @since 4.0

     */

    public static <T> Predicate<T> equalPredicate(final T object, final Equator<T> equator) {

        if (object == null) {

            return NullPredicate.nullPredicate();

        }

        return new EqualPredicate<>(object, equator);

    }

    /**

     * Constructor that performs no validation.

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

     *

     * @param object  the object to compare to

     */

    public EqualPredicate(final T object) {

        // do not use the DefaultEquator to keep backwards compatibility

        // the DefaultEquator returns also true if the two object references are equal

        this(object, null);

    }

    /**

     * Constructor that performs no validation.

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

     *

     * @param object  the object to compare to

     * @param equator  the equator to use for comparison

     * @since 4.0

     */

    public EqualPredicate(final T object, final Equator<T> equator) {

        super();

        iValue = object;

        this.equator = equator;

    }

    /**

     * Evaluates the predicate returning true if the input equals the stored value.

     *

     * @param object  the input object

     * @return true if input object equals stored value

     */

    @Override

    public boolean evaluate(final T object) {

        if (equator != null) {

            return equator.equate(iValue, object);

        }

        return iValue.equals(object);

    }

    /**

     * Gets the value.

     *

     * @return the value

     * @since 3.1

     */

    public Object getValue() {

        return iValue;

    }

}