src/main/java/org/apache/commons/lang3/mutable/MutableDouble.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;

/**
 * A mutable {@code double} wrapper.
 * <p>
 * Note that as MutableDouble does not extend Double, it is not treated by String.format as a Double parameter.
 *
 * @see Double
 * @since 2.1
 */
public class MutableDouble extends Number implements Comparable<MutableDouble>, Mutable<Number> {

    /**
     * Required for serialization support.
     *
     * @see java.io.Serializable
     */
    private static final long serialVersionUID = 1587163916L;

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

    /**
     * Constructs a new MutableDouble with the default value of zero.
     */
    public MutableDouble() {
        super();
    }

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

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

    /**
     * Constructs a new MutableDouble parsing the given string.
     *
     * @param value  the string to parse, not null
     * @throws NumberFormatException if the string cannot be parsed into a double
     * @since 2.5
     */
    public MutableDouble(final String value) {
        super();
        this.value = Double.parseDouble(value);
    }

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

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

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

    //-----------------------------------------------------------------------
    /**
     * Checks whether the double value is the special NaN value.
     *
     * @return true if NaN
     */
    public boolean isNaN() {
        return Double.isNaN(value);
    }

    /**
     * Checks whether the double value is infinite.
     *
     * @return true if infinite
     */
    public boolean isInfinite() {
        return Double.isInfinite(value);
    }

    //-----------------------------------------------------------------------
    /**
     * Increments the value.
     *
     * @since 2.2
     */
    public void increment() {
        value++;
    }

    /**
     * Increments this instance's value by 1; this method returns the value associated with the instance
     * immediately prior to the increment operation. This method is not thread safe.
     *
     * @return the value associated with the instance before it was incremented
     * @since 3.5
     */
    public double getAndIncrement() {
        final double last = value;
        value++;
        return last;
    }

    /**
     * Increments this instance's value by 1; this method returns the value associated with the instance
     * immediately after the increment operation. This method is not thread safe.
     *
     * @return the value associated with the instance after it is incremented
     * @since 3.5
     */
    public double incrementAndGet() {
        value++;
        return value;
    }

    /**
     * Decrements the value.
     *
     * @since 2.2
     */
    public void decrement() {
        value--;
    }

    /**
     * Decrements this instance's value by 1; this method returns the value associated with the instance
     * immediately prior to the decrement operation. This method is not thread safe.
     *
     * @return the value associated with the instance before it was decremented
     * @since 3.5
     */
    public double getAndDecrement() {
        final double last = value;
        value--;
        return last;
    }

    /**
     * Decrements this instance's value by 1; this method returns the value associated with the instance
     * immediately after the decrement operation. This method is not thread safe.
     *
     * @return the value associated with the instance after it is decremented
     * @since 3.5
     */
    public double decrementAndGet() {
        value--;
        return value;
    }

    //-----------------------------------------------------------------------
    /**
     * Adds a value to the value of this instance.
     *
     * @param operand  the value to add
     * @since 2.2
     */
    public void add(final double operand) {
        this.value += operand;
    }

    /**
     * Adds a value to the value of this instance.
     *
     * @param operand  the value to add, not null
     * @throws NullPointerException if the object is null
     * @since 2.2
     */
    public void add(final Number operand) {
        this.value += operand.doubleValue();
    }

    /**
     * Subtracts a value from the value of this instance.
     *
     * @param operand  the value to subtract, not null
     * @since 2.2
     */
    public void subtract(final double operand) {
        this.value -= operand;
    }

    /**
     * Subtracts a value from the value of this instance.
     *
     * @param operand  the value to subtract, not null
     * @throws NullPointerException if the object is null
     * @since 2.2
     */
    public void subtract(final Number operand) {
        this.value -= operand.doubleValue();
    }

    /**
     * Increments this instance's value by {@code operand}; this method returns the value associated with the instance
     * immediately after the addition operation. This method is not thread safe.
     *
     * @param operand the quantity to add, not null
     * @return the value associated with this instance after adding the operand
     * @since 3.5
     */
    public double addAndGet(final double operand) {
        this.value += operand;
        return value;
    }

    /**
     * Increments this instance's value by {@code operand}; this method returns the value associated with the instance
     * immediately after the addition operation. This method is not thread safe.
     *
     * @param operand the quantity to add, not null
     * @throws NullPointerException if {@code operand} is null
     * @return the value associated with this instance after adding the operand
     * @since 3.5
     */
    public double addAndGet(final Number operand) {
        this.value += operand.doubleValue();
        return value;
    }

    /**
     * Increments this instance's value by {@code operand}; this method returns the value associated with the instance
     * immediately prior to the addition operation. This method is not thread safe.
     *
     * @param operand the quantity to add, not null
     * @return the value associated with this instance immediately before the operand was added
     * @since 3.5
     */
    public double getAndAdd(final double operand) {
        final double last = value;
        this.value += operand;
        return last;
    }

    /**
     * Increments this instance's value by {@code operand}; this method returns the value associated with the instance
     * immediately prior to the addition operation. This method is not thread safe.
     *
     * @param operand the quantity to add, not null
     * @throws NullPointerException if {@code operand} is null
     * @return the value associated with this instance immediately before the operand was added
     * @since 3.5
     */
    public double getAndAdd(final Number operand) {
        final double last = value;
        this.value += operand.doubleValue();
        return last;
    }

    //-----------------------------------------------------------------------
    // shortValue and byteValue rely on Number implementation
    /**
     * Returns the value of this MutableDouble as an int.
     *
     * @return the numeric value represented by this object after conversion to type int.
     */
    @Override
    public int intValue() {
        return (int) value;
    }

    /**
     * Returns the value of this MutableDouble as a long.
     *
     * @return the numeric value represented by this object after conversion to type long.
     */
    @Override
    public long longValue() {
        return (long) value;
    }

    /**
     * Returns the value of this MutableDouble as a float.
     *
     * @return the numeric value represented by this object after conversion to type float.
     */
    @Override
    public float floatValue() {
        return (float) value;
    }

    /**
     * Returns the value of this MutableDouble as a double.
     *
     * @return the numeric value represented by this object after conversion to type double.
     */
    @Override
    public double doubleValue() {
        return value;
    }

    //-----------------------------------------------------------------------
    /**
     * Gets this mutable as an instance of Double.
     *
     * @return a Double instance containing the value from this mutable, never null
     */
    public Double toDouble() {
        return Double.valueOf(doubleValue());
    }

    //-----------------------------------------------------------------------
    /**
     * 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 Double} object that represents a double that has the identical
     * bit pattern to the bit pattern of the double represented by this object. For this purpose, two
     * {@code double} values are considered to be the same if and only if the method
     * {@link Double#doubleToLongBits(double)}returns the same long value when applied to each.
     * <p>
     * Note that in most cases, for two instances of class {@code Double},{@code d1} and {@code d2},
     * the value of {@code d1.equals(d2)} is {@code true} if and only if <blockquote>
     *
     * <pre>
     *   d1.doubleValue()&nbsp;== d2.doubleValue()
     * </pre>
     *
     * </blockquote>
     * <p>
     * also has the value {@code true}. However, there are two exceptions:
     * <ul>
     * <li>If {@code d1} and {@code d2} both represent {@code Double.NaN}, then the
     * {@code equals} method returns {@code true}, even though {@code Double.NaN==Double.NaN} has
     * the value {@code false}.
     * <li>If {@code d1} represents {@code +0.0} while {@code d2} represents {@code -0.0},
     * or vice versa, the {@code equal} test has the value {@code false}, even though
     * {@code +0.0==-0.0} has the value {@code true}. This allows hashtables to operate properly.
     * </ul>
     *
     * @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) {
        return obj instanceof MutableDouble
            && Double.doubleToLongBits(((MutableDouble) obj).value) == Double.doubleToLongBits(value);
    }

    /**
     * Returns a suitable hash code for this mutable.
     *
     * @return a suitable hash code
     */
    @Override
    public int hashCode() {
        final long bits = Double.doubleToLongBits(value);
        return (int) (bits ^ bits >>> 32);
    }

    //-----------------------------------------------------------------------
    /**
     * 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
     */
    @Override
    public int compareTo(final MutableDouble other) {
        return Double.compare(this.value, other.value);
    }

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

}