/*

 * 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.lang3.mutable;

import java.io.Serializable;

/**

 * A mutable {@code Object} wrapper.

 *

 * @param <T> the type to set and get

 * @since 2.1

 */

public class MutableObject<T> implements Mutable<T>, Serializable {

    /**

     * Required for serialization support.

     *

     * @see java.io.Serializable

     */

    private static final long serialVersionUID = 86241875189L;

    /** The mutable value. */

    private T value;

    /**

     * Constructs a new MutableObject with the default value of {@code null}.

     */

    public MutableObject() {

        super();

    }

    /**

     * Constructs a new MutableObject with the specified value.

     *

     * @param value  the initial value to store

     */

    public MutableObject(final T value) {

        super();

        this.value = value;

    }

    //-----------------------------------------------------------------------

    /**

     * Gets the value.

     *

     * @return the value, may be null

     */

    @Override

    public T getValue() {

        return this.value;

    }

    /**

     * Sets the value.

     *

     * @param value  the value to set

     */

    @Override

    public void setValue(final T value) {

        this.value = value;

    }

    //-----------------------------------------------------------------------

    /**

     * <p>

     * Compares this object against the specified object. The result is {@code true} if and only if the argument

     * is not {@code null} and is a {@code MutableObject} object that contains the same {@code T}

     * value as this object.

     * </p>

     *

     * @param obj  the object to compare with, {@code null} returns {@code false}

     * @return  {@code true} if the objects are the same;

     *          {@code true} if the objects have equivalent {@code value} fields;

     *          {@code false} otherwise.

     */

    @Override

    public boolean equals(final Object obj) {

        if (obj == null) {

            return false;

        }

        if (this == obj) {

            return true;

        }

        if (this.getClass() == obj.getClass()) {

            final MutableObject<?> that = (MutableObject<?>) obj;

            return this.value.equals(that.value);

        }

        return false;

    }

    /**

     * Returns the value's hash code or {@code 0} if the value is {@code null}.

     *

     * @return the value's hash code or {@code 0} if the value is {@code null}.

     */

    @Override

    public int hashCode() {

        return value == null ? 0 : value.hashCode();

    }

    //-----------------------------------------------------------------------

    /**

     * Returns the String value of this mutable.

     *

     * @return the mutable value as a string

     */

    @Override

    public String toString() {

        return value == null ? "null" : value.toString();

    }

}