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1   /*
2    * Copyright 2001-2005 The Apache Software Foundation
3    *
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    *
8    *     http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  package org.apache.commons.net.nntp;
17  
18  import java.util.Calendar;
19  
20  /***
21   * The NewGroupsOrNewsQuery class.  This is used to issue NNTP NEWGROUPS and
22   * NEWNEWS queries, implemented by
23   * {@link org.apache.commons.net.nntp.NNTPClient#listNewNewsgroups listNewNewsGroups }
24   *  and
25   * {@link org.apache.commons.net.nntp.NNTPClient#listNewNews listNewNews }
26   *  respectively.  It prevents you from having to format
27   * date, time, distribution, and newgroup arguments.
28   * <p>
29   * You might use the class as follows:
30   * <pre>
31   * query = new NewsGroupsOrNewsQuery(new GregorianCalendar(97, 11, 15), false);
32   * query.addDistribution("comp");
33   * NewsgroupInfo[] newsgroups = client.listNewgroups(query);
34   * </pre>
35   * This will retrieve the list of newsgroups starting with the comp.
36   * distribution prefix created since midnight 11/15/97.
37   * <p>
38   * <p>
39   * @author Daniel F. Savarese
40   * @see NNTPClient
41   ***/
42  
43  public final class NewGroupsOrNewsQuery
44  {
45      private String __date, __time;
46      private StringBuffer __distributions;
47      private StringBuffer __newsgroups;
48      private boolean __isGMT;
49  
50  
51      /***
52       * Creates a new query using the given time as a reference point.
53       * <p>
54       * @param date  The date since which new groups or news have arrived.
55       * @param gmt   True if the date should be considered as GMT, false if not.
56       ***/
57      public NewGroupsOrNewsQuery(Calendar date, boolean gmt)
58      {
59          int num;
60          String str;
61          StringBuffer buffer;
62  
63          __distributions = null;
64          __newsgroups = null;
65          __isGMT = gmt;
66  
67          buffer = new StringBuffer();
68  
69          // Get year
70          num = date.get(Calendar.YEAR);
71          str = Integer.toString(num);
72          num = str.length();
73  
74          if (num >= 2)
75              buffer.append(str.substring(num - 2));
76          else
77              buffer.append("00");
78  
79          // Get month
80          num = date.get(Calendar.MONTH) + 1;
81          str = Integer.toString(num);
82          num = str.length();
83  
84          if (num == 1)
85          {
86              buffer.append('0');
87              buffer.append(str);
88          }
89          else if (num == 2)
90              buffer.append(str);
91          else
92              buffer.append("01");
93  
94          // Get day
95          num = date.get(Calendar.DAY_OF_MONTH);
96          str = Integer.toString(num);
97          num = str.length();
98  
99          if (num == 1)
100         {
101             buffer.append('0');
102             buffer.append(str);
103         }
104         else if (num == 2)
105             buffer.append(str);
106         else
107             buffer.append("01");
108 
109         __date = buffer.toString();
110 
111         buffer.setLength(0);
112 
113         // Get hour
114         num = date.get(Calendar.HOUR_OF_DAY);
115         str = Integer.toString(num);
116         num = str.length();
117 
118         if (num == 1)
119         {
120             buffer.append('0');
121             buffer.append(str);
122         }
123         else if (num == 2)
124             buffer.append(str);
125         else
126             buffer.append("00");
127 
128         // Get minutes
129         num = date.get(Calendar.MINUTE);
130         str = Integer.toString(num);
131         num = str.length();
132 
133         if (num == 1)
134         {
135             buffer.append('0');
136             buffer.append(str);
137         }
138         else if (num == 2)
139             buffer.append(str);
140         else
141             buffer.append("00");
142 
143 
144         // Get seconds
145         num = date.get(Calendar.SECOND);
146         str = Integer.toString(num);
147         num = str.length();
148 
149         if (num == 1)
150         {
151             buffer.append('0');
152             buffer.append(str);
153         }
154         else if (num == 2)
155             buffer.append(str);
156         else
157             buffer.append("00");
158 
159         __time = buffer.toString();
160     }
161 
162 
163     /***
164      * Add a newsgroup to the list of newsgroups being queried.  Newsgroups
165      * added this way are only meaningful to the NEWNEWS command.  Newsgroup
166      * names may include the <code> * </code> wildcard, as in
167      * <code>comp.lang.* </code> or <code> comp.lang.java.* </code>.  Adding
168      * at least one newsgroup is mandatory for the NEWNEWS command.
169      * <p>
170      * @param newsgroup  The newsgroup to add to the list of groups to be
171      *                   checked for new news.
172      ***/
173     public void addNewsgroup(String newsgroup)
174     {
175         if (__newsgroups != null)
176             __newsgroups.append(',');
177         else
178             __newsgroups = new StringBuffer();
179         __newsgroups.append(newsgroup);
180     }
181 
182 
183     /***
184      * Add a newsgroup to the list of newsgroups being queried, but indicate
185      * that group should not be checked for new news.  Newsgroups
186      * added this way are only meaningful to the NEWNEWS command.
187      * Newsgroup names may include the <code> * </code> wildcard, as in
188      * <code>comp.lang.* </code> or <code> comp.lang.java.* </code>.
189      * <p>
190      * The following would create a query that searched for new news in
191      * all comp.lang.java newsgroups except for comp.lang.java.advocacy.
192      * <pre>
193      * query.addNewsgroup("comp.lang.java.*");
194      * query.omitNewsgroup("comp.lang.java.advocacy");
195      * </pre>
196      * <p>
197      * @param newsgroup  The newsgroup to add to the list of groups to be
198      *                   checked for new news, but which should be omitted from
199      *                   the search for new news..
200      ***/
201     public void omitNewsgroup(String newsgroup)
202     {
203         addNewsgroup("!" + newsgroup);
204     }
205 
206 
207     /***
208      * Add a distribution group to the query.  The distribution part of a
209      * newsgroup is the segment of the name preceding the first dot (e.g.,
210      * comp, alt, rec).  Only those newsgroups matching one of the
211      * distributions or, in the case of NEWNEWS, an article in a newsgroup
212      * matching one of the distributions, will be reported as a query result.
213      * Adding distributions is purely optional.
214      * <p>
215      * @param distribution A distribution to add to the query.
216      ***/
217     public void addDistribution(String distribution)
218     {
219         if (__distributions != null)
220             __distributions.append(',');
221         else
222             __distributions = new StringBuffer();
223         __distributions.append(distribution);
224     }
225 
226     /***
227      * Return the NNTP query formatted date (year, month, day in the form
228      * YYMMDD.
229      * <p>
230      * @return The NNTP query formatted date.
231      ***/
232     public String getDate()
233     {
234         return __date;
235     }
236 
237     /***
238      * Return the NNTP query formatted time (hour, minutes, seconds in the form
239      * HHMMSS.
240      * <p>
241      * @return The NNTP query formatted time.
242      ***/
243     public String getTime()
244     {
245         return __time;
246     }
247 
248     /***
249      * Return whether or not the query date should be treated as GMT.
250      * <p>
251      * @return True if the query date is to be treated as GMT, false if not.
252      ***/
253     public boolean isGMT()
254     {
255         return __isGMT;
256     }
257 
258     /***
259      * Return the comma separated list of distributions.  This may be null
260      * if there are no distributions.
261      * <p>
262      * @return The list of distributions, which may be null if no distributions
263      *         have been specified.
264      ***/
265     public String getDistributions()
266     {
267         return (__distributions == null ? null : __distributions.toString());
268     }
269 
270     /***
271      * Return the comma separated list of newsgroups.  This may be null
272      * if there are no newsgroups
273      * <p>
274      * @return The list of newsgroups, which may be null if no newsgroups
275      *         have been specified.
276      ***/
277     public String getNewsgroups()
278     {
279         return (__newsgroups == null ? null : __newsgroups.toString());
280     }
281 }