001 /*
002 * Copyright 2004 Stephen J. McConnell.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
013 * implied.
014 *
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018
019 package net.dpml.metro.info;
020
021 import java.io.Serializable;
022
023 import net.dpml.component.Directive;
024
025 /**
026 * A <code>PartReference</code> is a serializable object that contains a key and
027 * an associated part.
028 *
029 * @author <a href="http://www.dpml.net">Digital Product Meta Library</a>
030 * @version 1.0.4
031 */
032 public class PartReference implements Serializable, Comparable
033 {
034 /**
035 * Serial version identifier.
036 */
037 static final long serialVersionUID = 1L;
038
039 /**
040 * The key.
041 */
042 private final String m_key;
043
044 /**
045 * The supplied argument.
046 */
047 private final Directive m_directive;
048
049 /**
050 * The reference priority.
051 */
052 private final int m_priority;
053
054 /**
055 * Creation of a new part reference.
056 *
057 * @param key the key identifying this part within the scope of its container
058 * @param directive the directive
059 */
060 public PartReference( final String key, Directive directive )
061 {
062 this( key, directive, 0 );
063 }
064
065 /**
066 * Creation of a new part reference.
067 *
068 * @param key the key identifying this part within the scope of its container
069 * @param directive the directive
070 * @param priority the relative priority
071 */
072 public PartReference( final String key, Directive directive, int priority )
073 {
074 if( null == key )
075 {
076 throw new NullPointerException( "key" );
077 }
078 if( null == directive )
079 {
080 throw new NullPointerException( "directive" );
081 }
082 m_key = key;
083 m_directive = directive;
084 m_priority = priority;
085 }
086
087 /**
088 * Return the key.
089 * @return the key
090 */
091 public String getKey()
092 {
093 return m_key;
094 }
095
096 /**
097 * Return the directive.
098 * @return the directive
099 */
100 public Directive getDirective()
101 {
102 return m_directive;
103 }
104
105 /**
106 * Return the priority value.
107 * @return the priority ranking of this reference
108 */
109 public int getPriority()
110 {
111 return m_priority;
112 }
113
114 /**
115 * Compare this object with the supplied object.
116 * @param other the object to compare with
117 * @return the result
118 */
119 public int compareTo( Object other )
120 {
121 if( null == other )
122 {
123 throw new NullPointerException( "other" );
124 }
125 else if( other instanceof PartReference )
126 {
127 PartReference ref = (PartReference) other;
128 Integer p1 = new Integer( m_priority );
129 Integer p2 = new Integer( ref.m_priority );
130 return p1.compareTo( p2 );
131 }
132 else
133 {
134 String suspect = other.getClass().getName();
135 throw new IllegalArgumentException( suspect );
136 }
137 }
138
139 /**
140 * Test if the supplied object is equal to this object.
141 * @param other the object to compare with this instance
142 * @return TRUE if the supplied object is equal to this object
143 */
144 public boolean equals( Object other )
145 {
146 if( null == other )
147 {
148 return false;
149 }
150 else
151 {
152 if( !( other instanceof PartReference ) )
153 {
154 return false;
155 }
156 else
157 {
158 PartReference reference = (PartReference) other;
159 if( !m_key.equals( reference.getKey() ) )
160 {
161 return false;
162 }
163 else if( !m_directive.equals( reference.m_directive ) )
164 {
165 return false;
166 }
167 else
168 {
169 return m_priority == reference.m_priority;
170 }
171 }
172 }
173 }
174
175 /**
176 * Return the hashcode for the instance.
177 * @return the instance hashcode
178 */
179 public int hashCode()
180 {
181 int hash = m_key.hashCode();
182 hash ^= m_directive.hashCode();
183 hash ^= m_priority;
184 return hash;
185 }
186
187 /**
188 * Return a string representation of the instance.
189 * @return the string representation
190 */
191 public String toString()
192 {
193 return "[reference: key=" + m_key + "directive=" + m_directive + "]";
194 }
195 }