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:
018: package org.apache.commons.lang.mutable;
019:
020: import java.io.Serializable;
021:
022: /**
023: * A mutable <code>Object</code> wrapper.
024: *
025: * @since 2.1
026: * @version $Id: MutableObject.java 437554 2006-08-28 06:21:41Z bayard $
027: */
028: public class MutableObject implements Mutable, 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 Object 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
051: * a value.
052: */
053: public MutableObject(Object value) {
054: super ();
055: this .value = value;
056: }
057:
058: //-----------------------------------------------------------------------
059: /**
060: * Gets the value.
061: *
062: * @return the value
063: */
064: public Object getValue() {
065: return this .value;
066: }
067:
068: /**
069: * Sets the value.
070: *
071: * @param value
072: * the value to set
073: */
074: public void setValue(Object value) {
075: this .value = value;
076: }
077:
078: //-----------------------------------------------------------------------
079: /**
080: * Compares this object against the specified object. The result is <code>true</code> if and only if the argument
081: * is not <code>null</code> and is a <code>MutableObject</code> object that contains the same <code>Object</code>
082: * value as this object.
083: *
084: * @param obj
085: * the object to compare with.
086: * @return <code>true</code> if the objects are the same; <code>false</code> otherwise.
087: */
088: public boolean equals(Object obj) {
089: if (obj instanceof MutableObject) {
090: Object other = ((MutableObject) obj).value;
091: return value == other
092: || (value != null && value.equals(other));
093: }
094: return false;
095: }
096:
097: /**
098: * Returns the value's hash code or <code>0</code> if the value is <code>null</code>.
099: *
100: * @return the value's hash code or <code>0</code> if the value is <code>null</code>.
101: */
102: public int hashCode() {
103: return value == null ? 0 : value.hashCode();
104: }
105:
106: /**
107: * Returns the String value of this mutable.
108: *
109: * @return the mutable value as a string
110: */
111: public String toString() {
112: return value == null ? "null" : value.toString();
113: }
114:
115: }
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