DeweyDecimal


1   /*
2    * Copyright (C) The Spice Group. All rights reserved.
3    *
4    * This software is published under the terms of the Spice
5    * Software License version 1.1, a copy of which has been included
6    * with this distribution in the LICENSE.txt file.
7    */
8   package org.codehaus.loom.extension;
9   
10  import java.util.StringTokenizer  ;
11  
12  /**
13   * Utility class to contain version numbers in "Dewey Decimal" syntax.  Numbers
14   * in the "Dewey Decimal" syntax consist of positive decimal integers separated
15   * by periods ".".  For example, "2.0" or "1.2.3.4.5.6.7".  This allows an
16   * extensible number to be used to represent major, minor, micro, etc versions.
17   * The version number must begin with a number.
18   *
19   * @author Peter Donald
20   * @version $Revision: 1.1 $ $Date: 2004/04/19 21:40:38 $
21   */
22  public final class DeweyDecimal
23  {
24      ///Array of components that make up DeweyDecimal
25      private int[] m_components;
26  
27      /**
28       * Construct a DeweyDecimal from an array of integer components.
29       *
30       * @param components an array of integer components.
31       */
32      public DeweyDecimal( final int[] components )
33      {
34          m_components = new int[ components.length ];
35          for( int i = 0; i < m_components.length; i++ )
36          {
37              m_components[ i ] = components[ i ];
38          }
39      }
40  
41      /**
42       * Construct a DeweyDecimal from string in DeweyDecimal format.
43       *
44       * @param string the string in dewey decimal format
45       * @throws java.lang.NumberFormatException if string is malformed
46       */
47      public DeweyDecimal( final String   string )
48          throws NumberFormatException  
49      {
50          final StringTokenizer   tokenizer = new StringTokenizer  ( string,
51                                                                 ".",
52                                                                 true );
53          final int size = tokenizer.countTokens();
54          m_components = new int[ ( size + 1 ) / 2 ];
55          for( int i = 0; i < m_components.length; i++ )
56          {
57              final String   component = tokenizer.nextToken();
58              if( component.equals( "" ) )
59              {
60                  throw new NumberFormatException  ( "Empty component in string" );
61              }
62              m_components[ i ] = Integer.parseInt( component );
63              //Strip '.' token
64              if( tokenizer.hasMoreTokens() )
65              {
66                  tokenizer.nextToken();
67                  //If it ended in a dot, throw an exception
68                  if( !tokenizer.hasMoreTokens() )
69                  {
70                      final String   message = "DeweyDecimal ended in a '.'";
71                      throw new NumberFormatException  ( message );
72                  }
73              }
74          }
75      }
76  
77      /**
78       * Return number of components in <code>DeweyDecimal</code>.
79       *
80       * @return the number of components in dewey decimal
81       */
82      public int getSize()
83      {
84          return m_components.length;
85      }
86  
87      /**
88       * Return the component at specified index.
89       *
90       * @param index the index of components
91       * @return the value of component at index
92       */
93      public int get( final int index )
94      {
95          return m_components[ index ];
96      }
97  
98      /**
99       * Return <code>true</code> if this <code>DeweyDecimal</code> is equal to
100      * the other <code>DeweyDecimal</code>.
101      *
102      * @param other the other DeweyDecimal
103      * @return true if equal to other DeweyDecimal, false otherwise
104      */
105     public boolean isEqual( final DeweyDecimal other )
106     {
107         final int max = Math.max( other.m_components.length,
108                                   m_components.length );
109         for( int i = 0; i < max; i++ )
110         {
111             final int component1 = ( i < m_components.length ) ?
112                                    m_components[ i ] :
113                                    0;
114             final int component2 = ( i < other.m_components.length ) ?
115                                    other.m_components[ i ] :
116                                    0;
117             if( component2 != component1 )
118             {
119                 return false;
120             }
121         }
122         return true; // Exact match
123     }
124 
125     /**
126      * Return <code>true</code> if this <code>DeweyDecimal</code> is less than
127      * the other <code>DeweyDecimal</code>.
128      *
129      * @param other the other DeweyDecimal
130      * @return true if less than other DeweyDecimal, false otherwise
131      */
132     public boolean isLessThan( final DeweyDecimal other )
133     {
134         return !isGreaterThanOrEqual( other );
135     }
136 
137     /**
138      * Return <code>true</code> if this <code>DeweyDecimal</code> is less than
139      * or equal to the other <code>DeweyDecimal</code>.
140      *
141      * @param other the other DeweyDecimal
142      * @return true if less than or equal to other DeweyDecimal, false
143      *         otherwise
144      */
145     public boolean isLessThanOrEqual( final DeweyDecimal other )
146     {
147         return !isGreaterThan( other );
148     }
149 
150     /**
151      * Return <code>true</code> if this <code>DeweyDecimal</code> is greater
152      * than the other <code>DeweyDecimal</code>.
153      *
154      * @param other the other DeweyDecimal
155      * @return true if greater than other DeweyDecimal, false otherwise
156      */
157     public boolean isGreaterThan( final DeweyDecimal other )
158     {
159         final int max = Math.max( other.m_components.length,
160                                   m_components.length );
161         for( int i = 0; i < max; i++ )
162         {
163             final int component1 = ( i < m_components.length ) ?
164                                    m_components[ i ] :
165                                    0;
166             final int component2 = ( i < other.m_components.length ) ?
167                                    other.m_components[ i ] :
168                                    0;
169             if( component2 > component1 )
170             {
171                 return false;
172             }
173             if( component2 < component1 )
174             {
175                 return true;
176             }
177         }
178         return false; // Exact match
179     }
180 
181     /**
182      * Return <code>true</code> if this <code>DeweyDecimal</code> is greater
183      * than or equal to the other <code>DeweyDecimal</code>.
184      *
185      * @param other the other DeweyDecimal
186      * @return true if greater than or equal to other DeweyDecimal, false
187      *         otherwise
188      */
189     public boolean isGreaterThanOrEqual( final DeweyDecimal other )
190     {
191         final int max = Math.max( other.m_components.length,
192                                   m_components.length );
193         for( int i = 0; i < max; i++ )
194         {
195             final int component1 = ( i < m_components.length ) ?
196                                    m_components[ i ] :
197                                    0;
198             final int component2 = ( i < other.m_components.length ) ?
199                                    other.m_components[ i ] :
200                                    0;
201             if( component2 > component1 )
202             {
203                 return false;
204             }
205             if( component2 < component1 )
206             {
207                 return true;
208             }
209         }
210         return true; // Exact match
211     }
212 
213     /**
214      * Return string representation of <code>DeweyDecimal</code>.
215      *
216      * @return the string representation of DeweyDecimal.
217      */
218     public String   toString()
219     {
220         final StringBuffer   sb = new StringBuffer  ();
221         for( int i = 0; i < m_components.length; i++ )
222         {
223             if( i != 0 )
224             {
225                 sb.append( '.' );
226             }
227             sb.append( m_components[ i ] );
228         }
229         return sb.toString();
230     }
231 }
232
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