SizeSelector


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  
19  package org.apache.tools.ant.types.selectors;
20  
21  import java.io.File  ;
22  
23  import org.apache.tools.ant.types.Comparison;
24  import org.apache.tools.ant.types.EnumeratedAttribute;
25  import org.apache.tools.ant.types.Parameter;
26  
27  /**
28   * Selector that filters files based on their size.
29   *
30   * @since 1.5
31   */
32  public class SizeSelector extends BaseExtendSelector {
33  
34      /** Used for parameterized custom selector */
35      public static final String   SIZE_KEY = "value";
36      /** Used for parameterized custom selector */
37      public static final String   UNITS_KEY = "units";
38      /** Used for parameterized custom selector */
39      public static final String   WHEN_KEY = "when";
40  
41      private long size = -1;
42      private long multiplier = 1;
43      private long sizelimit = -1;
44      private Comparison when = Comparison.EQUAL;
45  
46      /**
47       * Creates a new <code>SizeSelector</code> instance.
48       *
49       */
50      public SizeSelector() {
51      }
52  
53      /**
54       * Returns a <code>String</code> object representing the specified
55       * SizeSelector. This is "{sizeselector value: " + <"compare",
56       * "less", "more", "equal"> + "}".
57       * @return a string describing this object
58       */
59      public String   toString() {
60          StringBuffer   buf = new StringBuffer  ("{sizeselector value: ");
61          buf.append(sizelimit);
62          buf.append("compare: ").append(when.getValue());
63          buf.append("}");
64          return buf.toString();
65      }
66  
67      /**
68       * A size selector needs to know what size to base its selecting on.
69       * This will be further modified by the multiplier to get an
70       * actual size limit.
71       *
72       * @param size the size to select against expressed in units.
73       */
74      public void setValue(long size) {
75          this.size = size;
76          if (multiplier != 0 && size > -1) {
77              sizelimit = size * multiplier;
78          }
79      }
80  
81      /**
82       * Sets the units to use for the comparison. This is a little
83       * complicated because common usage has created standards that
84       * play havoc with capitalization rules. Thus, some people will
85       * use "K" for indicating 1000's, when the SI standard calls for
86       * "k". Others have tried to introduce "K" as a multiple of 1024,
87       * but that falls down when you reach "M", since "m" is already
88       * defined as 0.001.
89       * <p>
90       * To get around this complexity, a number of standards bodies
91       * have proposed the 2^10 standard, and at least one has adopted
92       * it. But we are still left with a populace that isn't clear on
93       * how capitalization should work.
94       * <p>
95       * We therefore ignore capitalization as much as possible.
96       * Completely mixed case is not possible, but all upper and lower
97       * forms are accepted for all long and short forms. Since we have
98       * no need to work with the 0.001 case, this practice works here.
99       * <p>
100      * This function translates all the long and short forms that a
101      * unit prefix can occur in and translates them into a single
102      * multiplier.
103      *
104      * @param units The units to compare the size to, using an
105      *        EnumeratedAttribute.
106      */
107     public void setUnits(ByteUnits units) {
108         int i = units.getIndex();
109         multiplier = 0;
110         if (i > -1 && i < 4) {
111             multiplier = 1000;
112         } else if (i > 3 && i < 9) {
113             multiplier = 1024;
114         } else if (i > 8 && i < 13) {
115             multiplier = 1000000;
116         } else if (i > 12 && i < 18) {
117             multiplier = 1048576;
118         } else if (i > 17 && i < 22) {
119             multiplier = 1000000000L;
120         } else if (i > 21 && i < 27) {
121             multiplier = 1073741824L;
122         } else if (i > 26 && i < 31) {
123             multiplier = 1000000000000L;
124         } else if (i > 30 && i < 36) {
125             multiplier = 1099511627776L;
126         }
127         if (multiplier > 0 && size > -1) {
128             sizelimit = size * multiplier;
129         }
130     }
131 
132     /**
133      * This specifies when the file should be selected, whether it be
134      * when the file matches a particular size, when it is smaller,
135      * or whether it is larger.
136      *
137      * @param when The comparison to perform, an EnumeratedAttribute.
138      */
139     public void setWhen(SizeComparisons when) {
140         this.when = when;
141     }
142 
143     /**
144      * When using this as a custom selector, this method will be called.
145      * It translates each parameter into the appropriate setXXX() call.
146      *
147      * @param parameters the complete set of parameters for this selector.
148      */
149     public void setParameters(Parameter[] parameters) {
150         super.setParameters(parameters);
151         if (parameters != null) {
152             for (int i = 0; i < parameters.length; i++) {
153                 String   paramname = parameters[i].getName();
154                 if (SIZE_KEY.equalsIgnoreCase(paramname)) {
155                     try {
156                         setValue(new Long  (parameters[i].getValue()
157                         ).longValue());
158                     } catch (NumberFormatException   nfe) {
159                         setError("Invalid size setting "
160                                 + parameters[i].getValue());
161                     }
162                 } else if (UNITS_KEY.equalsIgnoreCase(paramname)) {
163                     ByteUnits units = new ByteUnits();
164                     units.setValue(parameters[i].getValue());
165                     setUnits(units);
166                 } else if (WHEN_KEY.equalsIgnoreCase(paramname)) {
167                     SizeComparisons scmp = new SizeComparisons();
168                     scmp.setValue(parameters[i].getValue());
169                     setWhen(scmp);
170                 } else {
171                     setError("Invalid parameter " + paramname);
172                 }
173             }
174         }
175     }
176 
177     /**
178      * <p>Checks to make sure all settings are kosher. In this case, it
179      * means that the size attribute has been set (to a positive value),
180      * that the multiplier has a valid setting, and that the size limit
181      * is valid. Since the latter is a calculated value, this can only
182      * fail due to a programming error.
183      * </p>
184      * <p>If a problem is detected, the setError() method is called.
185      * </p>
186      */
187     public void verifySettings() {
188         if (size < 0) {
189             setError("The value attribute is required, and must be positive");
190         } else if (multiplier < 1) {
191             setError("Invalid Units supplied, must be K,Ki,M,Mi,G,Gi,T,or Ti");
192         } else if (sizelimit < 0) {
193             setError("Internal error: Code is not setting sizelimit correctly");
194         }
195     }
196 
197     /**
198      * The heart of the matter. This is where the selector gets to decide
199      * on the inclusion of a file in a particular fileset.
200      *
201      * @param basedir A java.io.File object for the base directory.
202      * @param filename The name of the file to check.
203      * @param file A File object for this filename.
204      * @return whether the file should be selected or not.
205      */
206     public boolean isSelected(File   basedir, String   filename, File   file) {
207 
208         // throw BuildException on error
209         validate();
210 
211         // Directory size never selected for
212         if (file.isDirectory()) {
213             return true;
214         }
215         long diff = file.length() - sizelimit;
216         return when.evaluate(diff == 0 ? 0 : (int) (diff / Math.abs(diff)));
217     }
218 
219 
220     /**
221      * Enumerated attribute with the values for units.
222      * <p>
223      * This treats the standard SI units as representing powers of ten,
224      * as they should. If you want the powers of 2 that approximate
225      * the SI units, use the first two characters followed by a
226      * <code>bi</code>. So 1024 (2^10) becomes <code>kibi</code>,
227      * 1048576 (2^20) becomes <code>mebi</code>, 1073741824 (2^30)
228      * becomes <code>gibi</code>, and so on. The symbols are also
229      * accepted, and these are the first letter capitalized followed
230      * by an <code>i</code>. <code>Ki</code>, <code>Mi</code>,
231      * <code>Gi</code>, and so on. Capitalization variations on these
232      * are also accepted.
233      * <p>
234      * This binary prefix system is approved by the IEC and appears on
235      * its way for approval by other agencies, but it is not an SI
236      * standard. It disambiguates things for us, though.
237      */
238     public static class ByteUnits extends EnumeratedAttribute {
239         /**
240          * @return the values as an array of strings
241          */
242         public String  [] getValues() {
243             return new String  []{"K", "k", "kilo", "KILO",
244                                 "Ki", "KI", "ki", "kibi", "KIBI",
245                                 "M", "m", "mega", "MEGA",
246                                 "Mi", "MI", "mi", "mebi", "MEBI",
247                                 "G", "g", "giga", "GIGA",
248                                 "Gi", "GI", "gi", "gibi", "GIBI",
249                                 "T", "t", "tera", "TERA",
250            /* You wish! */      "Ti", "TI", "ti", "tebi", "TEBI"
251             };
252         }
253     }
254 
255     /**
256      * Enumerated attribute with the values for size comparison.
257      */
258     public static class SizeComparisons extends Comparison {
259     }
260 
261 }
262 
263
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags