001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 018package org.apache.commons.lang3.mutable; 019 020import java.io.Serializable; 021 022/** 023 * A mutable <code>Object</code> wrapper. 024 * 025 * @param <T> the type to set and get 026 * @since 2.1 027 */ 028public class MutableObject<T> implements Mutable<T>, Serializable { 029 030 /** 031 * Required for serialization support. 032 * 033 * @see java.io.Serializable 034 */ 035 private static final long serialVersionUID = 86241875189L; 036 037 /** The mutable value. */ 038 private T value; 039 040 /** 041 * Constructs a new MutableObject with the default value of <code>null</code>. 042 */ 043 public MutableObject() { 044 super(); 045 } 046 047 /** 048 * Constructs a new MutableObject with the specified value. 049 * 050 * @param value the initial value to store 051 */ 052 public MutableObject(final T value) { 053 super(); 054 this.value = value; 055 } 056 057 //----------------------------------------------------------------------- 058 /** 059 * Gets the value. 060 * 061 * @return the value, may be null 062 */ 063 @Override 064 public T getValue() { 065 return this.value; 066 } 067 068 /** 069 * Sets the value. 070 * 071 * @param value the value to set 072 */ 073 @Override 074 public void setValue(final T value) { 075 this.value = value; 076 } 077 078 //----------------------------------------------------------------------- 079 /** 080 * <p> 081 * Compares this object against the specified object. The result is <code>true</code> if and only if the argument 082 * is not <code>null</code> and is a <code>MutableObject</code> object that contains the same <code>T</code> 083 * value as this object. 084 * </p> 085 * 086 * @param obj the object to compare with, <code>null</code> returns <code>false</code> 087 * @return <code>true</code> if the objects are the same; 088 * <code>true</code> if the objects have equivalent <code>value</code> fields; 089 * <code>false</code> otherwise. 090 */ 091 @Override 092 public boolean equals(final Object obj) { 093 if (obj == null) { 094 return false; 095 } 096 if (this == obj) { 097 return true; 098 } 099 if (this.getClass() == obj.getClass()) { 100 final MutableObject<?> that = (MutableObject<?>) obj; 101 return this.value.equals(that.value); 102 } 103 return false; 104 } 105 106 /** 107 * Returns the value's hash code or <code>0</code> if the value is <code>null</code>. 108 * 109 * @return the value's hash code or <code>0</code> if the value is <code>null</code>. 110 */ 111 @Override 112 public int hashCode() { 113 return value == null ? 0 : value.hashCode(); 114 } 115 116 //----------------------------------------------------------------------- 117 /** 118 * Returns the String value of this mutable. 119 * 120 * @return the mutable value as a string 121 */ 122 @Override 123 public String toString() { 124 return value == null ? "null" : value.toString(); 125 } 126 127}