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; import org.apache.commons.lang3.math.NumberUtils; /** * A mutable <code>int</code> wrapper. * <p> * Note that as MutableInt does not extend Integer, it is not treated by String.format as an Integer parameter. * * @see Integer * @since 2.1 * @version $Id$ */ public class MutableInt extends Number implements Comparable<MutableInt>, Mutable<Number> { /** * Required for serialization support. * * @see java.io.Serializable */ private static final long serialVersionUID = 512176391864L; /** The mutable value. */ private int value; /** * Constructs a new MutableInt with the default value of zero. */ public MutableInt() { super(); } /** * Constructs a new MutableInt with the specified value. * * @param value the initial value to store */ public MutableInt(final int value) { super(); this.value = value; } /** * Constructs a new MutableInt with the specified value. * * @param value the initial value to store, not null * @throws NullPointerException if the object is null */ public MutableInt(final Number value) { super(); this.value = value.intValue(); } /** * Constructs a new MutableInt parsing the given string. * * @param value the string to parse, not null * @throws NumberFormatException if the string cannot be parsed into an int * @since 2.5 */ public MutableInt(final String value) throws NumberFormatException { super(); this.value = Integer.parseInt(value); } //----------------------------------------------------------------------- /** * Gets the value as a Integer instance. * * @return the value as a Integer, never null */ @Override public Integer getValue() { return Integer.valueOf(this.value); } /** * Sets the value. * * @param value the value to set */ public void setValue(final int 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.intValue(); } //----------------------------------------------------------------------- /** * 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 int 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.intValue(); } /** * Subtracts a value from the value of this instance. * * @param operand the value to subtract, not null * @since Commons Lang 2.2 */ public void subtract(final int 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.intValue(); } //----------------------------------------------------------------------- // shortValue and byteValue rely on Number implementation /** * Returns the value of this MutableInt as an int. * * @return the numeric value represented by this object after conversion to type int. */ @Override public int intValue() { return value; } /** * Returns the value of this MutableInt as a long. * * @return the numeric value represented by this object after conversion to type long. */ @Override public long longValue() { return value; } /** * Returns the value of this MutableInt 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 MutableInt 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 Integer. * * @return a Integer instance containing the value from this mutable, never null */ public Integer toInteger() { return Integer.valueOf(intValue()); } //----------------------------------------------------------------------- /** * Compares this object to the specified object. The result is <code>true</code> if and only if the argument is * not <code>null</code> and is a <code>MutableInt</code> object that contains the same <code>int</code> value * as this object. * * @param obj the object to compare with, null returns false * @return <code>true</code> if the objects are the same; <code>false</code> otherwise. */ @Override public boolean equals(final Object obj) { if (obj instanceof MutableInt) { return value == ((MutableInt) obj).intValue(); } return false; } /** * Returns a suitable hash code for this mutable. * * @return a suitable hash code */ @Override public int hashCode() { 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 */ @Override public int compareTo(final MutableInt other) { return NumberUtils.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); } }