MutableBoolean.java

/*
 * 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;

import org.apache.commons.lang3.BooleanUtils;

/**
 * A mutable {@code boolean} wrapper.
 * <p>
 * Note that as MutableBoolean does not extend Boolean, it is not treated by String.format as a Boolean parameter.
 * </p>
 *
 * @see Boolean
 * @since 2.2
 */
public class MutableBoolean implements Mutable<Boolean>, Serializable, Comparable<MutableBoolean> {

    /**
     * Required for serialization support.
     *
     * @see java.io.Serializable
     */
    private static final long serialVersionUID = -4830728138360036487L;

    /** The mutable value. */
    private boolean value;

    /**
     * Constructs a new MutableBoolean with the default value of false.
     */
    public MutableBoolean() {
    }

    /**
     * Constructs a new MutableBoolean with the specified value.
     *
     * @param value  the initial value to store
     */
    public MutableBoolean(final boolean value) {
        this.value = value;
    }

    /**
     * Constructs a new MutableBoolean with the specified value.
     *
     * @param value  the initial value to store, not null
     * @throws NullPointerException if the object is null
     */
    public MutableBoolean(final Boolean value) {
        this.value = value.booleanValue();
    }

    /**
     * Returns the value of this MutableBoolean as a boolean.
     *
     * @return the boolean value represented by this object.
     */
    public boolean booleanValue() {
        return value;
    }

    /**
     * Compares this mutable to another in ascending order.
     *
     * @param other  the other mutable to compare to, not null
     * @return negative if this is less, zero if equal, positive if greater
     *  where false is less than true
     */
    @Override
    public int compareTo(final MutableBoolean other) {
        return BooleanUtils.compare(this.value, other.value);
    }

    /**
     * Compares this object to the specified object. The result is {@code true} if and only if the argument is
     * not {@code null} and is an {@link MutableBoolean} object that contains the same
     * {@code boolean} value as this object.
     *
     * @param obj  the object to compare with, null returns false
     * @return {@code true} if the objects are the same; {@code false} otherwise.
     */
    @Override
    public boolean equals(final Object obj) {
        if (obj instanceof MutableBoolean) {
            return value == ((MutableBoolean) obj).booleanValue();
        }
        return false;
    }

    /**
     * Gets the value as a Boolean instance.
     *
     * @return the value as a Boolean, never null
     */
    @Override
    public Boolean getValue() {
        return Boolean.valueOf(this.value);
    }

    /**
     * Returns a suitable hash code for this mutable.
     *
     * @return the hash code returned by {@code Boolean.TRUE} or {@code Boolean.FALSE}
     */
    @Override
    public int hashCode() {
        return value ? Boolean.TRUE.hashCode() : Boolean.FALSE.hashCode();
    }

    /**
     * Checks if the current value is {@code false}.
     *
     * @return {@code true} if the current value is {@code false}
     * @since 2.5
     */
    public boolean isFalse() {
        return !value;
    }

    /**
     * Checks if the current value is {@code true}.
     *
     * @return {@code true} if the current value is {@code true}
     * @since 2.5
     */
    public boolean isTrue() {
        return value;
    }

    /**
     * Sets the value to false.
     *
     * @since 3.3
     */
    public void setFalse() {
        this.value = false;
    }

    /**
     * Sets the value to true.
     *
     * @since 3.3
     */
    public void setTrue() {
        this.value = true;
    }

    /**
     * Sets the value.
     *
     * @param value  the value to set
     */
    public void setValue(final boolean value) {
        this.value = value;
    }

    /**
     * Sets the value from any Boolean instance.
     *
     * @param value  the value to set, not null
     * @throws NullPointerException if the object is null
     */
    @Override
    public void setValue(final Boolean value) {
        this.value = value.booleanValue();
    }

    /**
     * Gets this mutable as an instance of Boolean.
     *
     * @return a Boolean instance containing the value from this mutable, never null
     * @since 2.5
     */
    public Boolean toBoolean() {
        return Boolean.valueOf(booleanValue());
    }

    /**
     * Returns the String value of this mutable.
     *
     * @return the mutable value as a string
     */
    @Override
    public String toString() {
        return String.valueOf(value);
    }

}