Java tutorial
/* * 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>float</code> wrapper. * <p> * Note that as MutableFloat does not extend Float, it is not treated by String.format as a Float parameter. * * @see Float * @since 2.1 * @version $Id$ */ public class MutableFloat extends Number implements Comparable<MutableFloat>, Mutable<Number> { /** * Required for serialization support. * * @see java.io.Serializable */ private static final long serialVersionUID = 5787169186L; /** The mutable value. */ private float value; /** * Constructs a new MutableFloat with the default value of zero. */ public MutableFloat() { super(); } /** * Constructs a new MutableFloat with the specified value. * * @param value the initial value to store */ public MutableFloat(final float value) { super(); this.value = value; } /** * Constructs a new MutableFloat with the specified value. * * @param value the initial value to store, not null * @throws NullPointerException if the object is null */ public MutableFloat(final Number value) { super(); this.value = value.floatValue(); } /** * Constructs a new MutableFloat parsing the given string. * * @param value the string to parse, not null * @throws NumberFormatException if the string cannot be parsed into a float * @since 2.5 */ public MutableFloat(final String value) throws NumberFormatException { super(); this.value = Float.parseFloat(value); } //----------------------------------------------------------------------- /** * Gets the value as a Float instance. * * @return the value as a Float, never null */ @Override public Float getValue() { return Float.valueOf(this.value); } /** * Sets the value. * * @param value the value to set */ public void setValue(final float 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.floatValue(); } //----------------------------------------------------------------------- /** * Checks whether the float value is the special NaN value. * * @return true if NaN */ public boolean isNaN() { return Float.isNaN(value); } /** * Checks whether the float value is infinite. * * @return true if infinite */ public boolean isInfinite() { return Float.isInfinite(value); } //----------------------------------------------------------------------- /** * Increments the value. * * @since Commons Lang 2.2 */ public void increment() { value++; } /** * Decrements the value. * * @since Commons Lang 2.2 */ public void decrement() { value--; } //----------------------------------------------------------------------- /** * Adds a value to the value of this instance. * * @param operand the value to add, not null * @since Commons Lang 2.2 */ public void add(final float 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 Commons Lang 2.2 */ public void add(final Number operand) { this.value += operand.floatValue(); } /** * Subtracts a value from the value of this instance. * * @param operand the value to subtract * @since Commons Lang 2.2 */ public void subtract(final float 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 Commons Lang 2.2 */ public void subtract(final Number operand) { this.value -= operand.floatValue(); } //----------------------------------------------------------------------- // shortValue and byteValue rely on Number implementation /** * Returns the value of this MutableFloat 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 MutableFloat 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 MutableFloat as a float. * * @return the numeric value represented by this object after conversion to type float. */ @Override public float floatValue() { return value; } /** * Returns the value of this MutableFloat 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 Float. * * @return a Float instance containing the value from this mutable, never null */ public Float toFloat() { return Float.valueOf(floatValue()); } //----------------------------------------------------------------------- /** * Compares this object against some other object. The result is <code>true</code> if and only if the argument is * not <code>null</code> and is a <code>Float</code> object that represents a <code>float</code> that has the * identical bit pattern to the bit pattern of the <code>float</code> represented by this object. For this * purpose, two float values are considered to be the same if and only if the method * {@link Float#floatToIntBits(float)}returns the same int value when applied to each. * <p> * Note that in most cases, for two instances of class <code>Float</code>,<code>f1</code> and <code>f2</code>, * the value of <code>f1.equals(f2)</code> is <code>true</code> if and only if <blockquote> * * <pre> * f1.floatValue() == f2.floatValue() * </pre> * * </blockquote> * <p> * also has the value <code>true</code>. However, there are two exceptions: * <ul> * <li>If <code>f1</code> and <code>f2</code> both represent <code>Float.NaN</code>, then the * <code>equals</code> method returns <code>true</code>, even though <code>Float.NaN==Float.NaN</code> has * the value <code>false</code>. * <li>If <code>f1</code> represents <code>+0.0f</code> while <code>f2</code> represents <code>-0.0f</code>, * or vice versa, the <code>equal</code> test has the value <code>false</code>, even though * <code>0.0f==-0.0f</code> has the value <code>true</code>. * </ul> * This definition allows hashtables to operate properly. * * @param obj the object to compare with, null returns false * @return <code>true</code> if the objects are the same; <code>false</code> otherwise. * @see java.lang.Float#floatToIntBits(float) */ @Override public boolean equals(final Object obj) { return obj instanceof MutableFloat && Float.floatToIntBits(((MutableFloat) obj).value) == Float.floatToIntBits(value); } /** * Returns a suitable hash code for this mutable. * * @return a suitable hash code */ @Override public int hashCode() { return Float.floatToIntBits(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 */ @Override public int compareTo(final MutableFloat other) { return Float.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); } }