BrowseInfo


1   /*
2    * BrowseInfo.java
3    *
4    * Version: $Revision: 1.9 $
5    *
6    * Date: $Date: 2005/04/20 14:23:12 $
7    *
8    * Copyright (c) 2002-2005, Hewlett-Packard Company and Massachusetts
9    * Institute of Technology.  All rights reserved.
10   *
11   * Redistribution and use in source and binary forms, with or without
12   * modification, are permitted provided that the following conditions are
13   * met:
14   *
15   * - Redistributions of source code must retain the above copyright
16   * notice, this list of conditions and the following disclaimer.
17   *
18   * - Redistributions in binary form must reproduce the above copyright
19   * notice, this list of conditions and the following disclaimer in the
20   * documentation and/or other materials provided with the distribution.
21   *
22   * - Neither the name of the Hewlett-Packard Company nor the name of the
23   * Massachusetts Institute of Technology nor the names of their
24   * contributors may be used to endorse or promote products derived from
25   * this software without specific prior written permission.
26   *
27   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
28   * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
29   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
30   * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
31   * HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
32   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
33   * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
34   * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
35   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
36   * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
37   * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
38   * DAMAGE.
39   */
40  package org.dspace.browse;
41  
42  import java.util.Collections  ;
43  import java.util.List  ;
44  
45  import org.dspace.content.Item;
46  
47  /**
48   * The results of a Browse method call.
49   * 
50   * <p>
51   * Results are a List of objects returned from the browse; each returned object
52   * is either a String (for getAuthors()) or an {@link org.dspace.content.Item}
53   * (for all the getItems.... methods). The list is readonly, and is guaranteed
54   * to be non-null.
55   * </p>
56   * 
57   * <p>
58   * overallPosition is the position of the first element of results within the
59   * Browse index. Positions begin with 0.
60   * </p>
61   * 
62   * <p>
63   * total is the number of objects in the index. Note that this is a snapshot,
64   * which is only guaranteed to be correct at the time the browse method was
65   * called.
66   * </p>
67   * 
68   * <p>
69   * offset is the position of the requested object within the results. This
70   * position is also 0-based.
71   * </p>
72   */
73  public class BrowseInfo
74  {
75      /**
76       * The results of the browse.
77       */
78      private List   results;
79  
80      /**
81       * The position of the first element of results within the Browse index.
82       * Positions begin with 0.
83       */
84      private int overallPosition;
85  
86      /**
87       * The position of the requested object within the results. Offsets begin
88       * with 0.
89       */
90      private int offset;
91  
92      /**
93       * The total number of items in the browse index.
94       */
95      private int total;
96  
97      /**
98       * True if this browse was cached.
99       */
100     private boolean cached;
101 
102     /**
103      * Constructor
104      * 
105      * @param results
106      *            A List of Browse results
107      * @param overallPosition
108      *            The position of the first returned item in the overall index
109      * @param total
110      *            The total number of items in the index
111      * @param offset
112      *            The position of the requested item in the set of results
113      */
114     public BrowseInfo(List   results, int overallPosition, int total, int offset)
115     {
116         if (results == null)
117         {
118             throw new IllegalArgumentException  ("Null result list not allowed");
119         }
120 
121         this.results = Collections.unmodifiableList(results);
122         this.overallPosition = overallPosition;
123         this.total = total;
124         this.offset = offset;
125     }
126 
127     /**
128      * The results of the Browse. Each member of the list is either a String
129      * (for the authors browse) or an {@link org.dspace.content.Item}(for the
130      * other browses).
131      * 
132      * @return Result list. This list cannot be modified.
133      */
134     public List   getResults()
135     {
136         return results;
137     }
138 
139     /**
140      * Return the results of the Browse as a String array.
141      * 
142      * @return The results of the Browse as a String array.
143      */
144     public String  [] getStringResults()
145     {
146         return (String  []) results.toArray(new String  [results.size()]);
147     }
148 
149     /**
150      * Return the results of the Browse as an Item array.
151      * 
152      * @return The results of the Browse as an Item array.
153      */
154     public Item[] getItemResults()
155     {
156         return (Item[]) results.toArray(new Item[results.size()]);
157     }
158 
159     /**
160      * Return the number of results.
161      * 
162      * @return The number of results.
163      */
164     public int getResultCount()
165     {
166         return results.size();
167     }
168 
169     /**
170      * Return the position of the results in index being browsed. This is 0 for
171      * the start of the index.
172      * 
173      * @return The position of the results in index being browsed.
174      */
175     public int getOverallPosition()
176     {
177         return overallPosition;
178     }
179 
180     /**
181      * Return the total number of items in the index.
182      * 
183      * @return The total number of items in the index.
184      */
185     public int getTotal()
186     {
187         return total;
188     }
189 
190     /**
191      * Return the position of the requested item or value in the set of results.
192      * 
193      * @return The position of the requested item or value in the set of results
194      */
195     public int getOffset()
196     {
197         return offset;
198     }
199 
200     /**
201      * True if there are no previous results from the browse.
202      * 
203      * @return True if there are no previous results from the browse
204      */
205     public boolean isFirst()
206     {
207         return overallPosition == 0;
208     }
209 
210     /**
211      * True if these are the last results from the browse.
212      * 
213      * @return True if these are the last results from the browse
214      */
215     public boolean isLast()
216     {
217         return (overallPosition + getResultCount()) == total;
218     }
219 
220     /**
221      * True if this browse was cached.
222      */
223     public boolean wasCached()
224     {
225         return cached;
226     }
227 
228     /**
229      * Set whether this browse was cached.
230      */
231     void setCached(boolean cached)
232     {
233         this.cached = cached;
234     }
235 }
236
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