DeweyDecimal


1   /*
2    *  Licensed to the Apache Software Foundation (ASF) under one or more
3    *  contributor license agreements.  See the NOTICE file distributed with
4    *  this work for additional information regarding copyright ownership.
5    *  The ASF licenses this file to You under the Apache License, Version 2.0
6    *  (the "License"); you may not use this file except in compliance with
7    *  the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   *  Unless required by applicable law or agreed to in writing, software
12   *  distributed under the License is distributed on an "AS IS" BASIS,
13   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   *  See the License for the specific language governing permissions and
15   *  limitations under the License.
16   *
17   */
18  package org.apache.tools.ant.util;
19  
20  import java.util.StringTokenizer  ;
21  
22  /**
23   * Utility class to contain version numbers in "Dewey Decimal"
24   * syntax.  Numbers in the "Dewey Decimal" syntax consist of positive
25   * decimal integers separated by periods ".".  For example, "2.0" or
26   * "1.2.3.4.5.6.7".  This allows an extensible number to be used to
27   * represent major, minor, micro, etc versions.  The version number
28   * must begin with a number.
29   *
30   */
31  public class DeweyDecimal {
32  
33      /** Array of components that make up DeweyDecimal */
34      private int[] components;
35  
36      /**
37       * Construct a DeweyDecimal from an array of integer components.
38       *
39       * @param components an array of integer components.
40       */
41      public DeweyDecimal(final int[] components) {
42          this.components = new int[components.length];
43  
44          for (int i = 0; i < components.length; i++) {
45              this.components[i] = components[i];
46          }
47      }
48  
49      /**
50       * Construct a DeweyDecimal from string in DeweyDecimal format.
51       *
52       * @param string the string in dewey decimal format
53       * @exception NumberFormatException if string is malformed
54       */
55      public DeweyDecimal(final String   string)
56          throws NumberFormatException   {
57          final StringTokenizer tokenizer = new StringTokenizer(string, ".", true);
58          final int size = tokenizer.countTokens();
59  
60          components = new int[ (size + 1) / 2 ];
61  
62          for (int i = 0; i < components.length; i++) {
63              final String   component = tokenizer.nextToken();
64              if (component.equals("")) {
65                  throw new NumberFormatException  ("Empty component in string");
66              }
67  
68              components[ i ] = Integer.parseInt(component);
69  
70              //Strip '.' token
71              if (tokenizer.hasMoreTokens()) {
72                  tokenizer.nextToken();
73  
74                  //If it ended in a dot, throw an exception
75                  if (!tokenizer.hasMoreTokens()) {
76                      throw new NumberFormatException  ("DeweyDecimal ended in a '.'");
77                  }
78              }
79          }
80      }
81  
82      /**
83       * Return number of components in <code>DeweyDecimal</code>.
84       *
85       * @return the number of components in dewey decimal
86       */
87      public int getSize() {
88          return components.length;
89      }
90  
91      /**
92       * Return the component at specified index.
93       *
94       * @param index the index of components
95       * @return the value of component at index
96       */
97      public int get(final int index) {
98          return components[ index ];
99      }
100 
101     /**
102      * Return <code>true</code> if this <code>DeweyDecimal</code> is
103      * equal to the other <code>DeweyDecimal</code>.
104      *
105      * @param other the other DeweyDecimal
106      * @return true if equal to other DeweyDecimal, false otherwise
107      */
108     public boolean isEqual(final DeweyDecimal other) {
109         final int max = Math.max(other.components.length, components.length);
110 
111         for (int i = 0; i < max; i++) {
112             final int component1 = (i < components.length) ? components[ i ] : 0;
113             final int component2 = (i < other.components.length) ? other.components[ i ] : 0;
114 
115             if (component2 != component1) {
116                 return false;
117             }
118         }
119 
120         return true; // Exact match
121     }
122 
123     /**
124      * Return <code>true</code> if this <code>DeweyDecimal</code> is
125      * less than the other <code>DeweyDecimal</code>.
126      *
127      * @param other the other DeweyDecimal
128      * @return true if less than other DeweyDecimal, false otherwise
129      */
130     public boolean isLessThan(final DeweyDecimal other) {
131         return !isGreaterThanOrEqual(other);
132     }
133 
134     /**
135      * Return <code>true</code> if this <code>DeweyDecimal</code> is
136      * less than or equal to the other <code>DeweyDecimal</code>.
137      *
138      * @param other the other DeweyDecimal
139      * @return true if less than or equal to other DeweyDecimal, false otherwise
140      */
141     public boolean isLessThanOrEqual(final DeweyDecimal other) {
142         return !isGreaterThan(other);
143     }
144 
145     /**
146      * Return <code>true</code> if this <code>DeweyDecimal</code> is
147      * greater than the other <code>DeweyDecimal</code>.
148      *
149      * @param other the other DeweyDecimal
150      * @return true if greater than other DeweyDecimal, false otherwise
151      */
152     public boolean isGreaterThan(final DeweyDecimal other) {
153         final int max = Math.max(other.components.length, components.length);
154 
155         for (int i = 0; i < max; i++) {
156             final int component1 = (i < components.length) ? components[ i ] : 0;
157             final int component2 = (i < other.components.length) ? other.components[ i ] : 0;
158 
159             if (component2 > component1) {
160                 return false;
161             }
162             if (component2 < component1) {
163                 return true;
164             }
165         }
166 
167         return false; // Exact match
168     }
169 
170     /**
171      * Return <code>true</code> if this <code>DeweyDecimal</code> is
172      * greater than or equal to the other <code>DeweyDecimal</code>.
173      *
174      * @param other the other DeweyDecimal
175      * @return true if greater than or equal to other DeweyDecimal, false otherwise
176      */
177     public boolean isGreaterThanOrEqual(final DeweyDecimal other) {
178         final int max = Math.max(other.components.length, components.length);
179 
180         for (int i = 0; i < max; i++) {
181             final int component1 = (i < components.length) ? components[ i ] : 0;
182             final int component2 = (i < other.components.length) ? other.components[ i ] : 0;
183 
184             if (component2 > component1) {
185                 return false;
186             }
187             if (component2 < component1) {
188                 return true;
189             }
190         }
191 
192         return true; // Exact match
193     }
194 
195     /**
196      * Return string representation of <code>DeweyDecimal</code>.
197      *
198      * @return the string representation of DeweyDecimal.
199      */
200     public String   toString() {
201         final StringBuffer   sb = new StringBuffer  ();
202 
203         for (int i = 0; i < components.length; i++) {
204             if (i != 0) {
205                 sb.append('.');
206             }
207             sb.append(components[ i ]);
208         }
209 
210         return sb.toString();
211     }
212 }
213
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