KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > jodd > servlet > tags > basic > IteratorTag


1 package jodd.servlet.tags.basic;
2
3 import java.io.IOException;
4 import java.util.Collection;
5 import java.util.Iterator;
6
7 import javax.servlet.jsp.JspTagException;
8 import javax.servlet.jsp.tagext.BodyContent;
9 import javax.servlet.jsp.tagext.BodyTagSupport;
10
11 /**
12  * Collection iterator tag. Iterates a <b>collection</b>, starting from
13  * <b>offset</b> and <b>length</b> number of items.
14  * For every itteration, tag returns following variables:
15  * <ul>
16  * <li>element - current element from the collection</li>
17  * <li>count - current iteration count, starting from 0</li>
18  * <li>index - current iteration index in collection</li>
19  * <li>total - total number of items in collection</li>
20  * </ul>
21  */
22 public class IteratorTag extends BodyTagSupport {
23
24     public final static String ELEMENT_NAME = "element";
25     public final static String COUNT_NAME = "count";
26     public final static String TOTAL_NAME = "total";
27     public final static String INDEX_NAME = "index";
28
29     private Iterator iterator = null;
30     private int index;
31     private Integer total;
32     private int count;
33
34     public void setCollection(Collection c) {
35         if (c.size() > 0) {
36             iterator = c.iterator();
37             total = new Integer(c.size());
38         }
39     }
40
41     private int offset = 0;
42     public void setOffset(int i) {
43         offset = i;
44     }
45     
46     private int lengthValue = 0;
47     private String length = null;
48     public void setLength(String s) {
49         length = s;
50     }
51
52     private void doIterator(Iterator i) {
53         pageContext.setAttribute(ELEMENT_NAME, i.next());
54         pageContext.setAttribute(COUNT_NAME, new Integer(count));
55         pageContext.setAttribute(TOTAL_NAME, total);
56         pageContext.setAttribute(INDEX_NAME, new Integer(index));
57         count++;
58         index++;
59         lengthValue--;
60     }
61
62     public int doStartTag() {
63         if (iterator == null) {
64             return SKIP_BODY;
65         }
66         count = 0; // reset count
67 index = 0; // reset index
68
69         if (length == null) { // length parameter
70 lengthValue = total.intValue();
71         } else {
72             lengthValue = Integer.parseInt(length);
73         }
74         if (lengthValue <= 0) { // zero length
75 return SKIP_BODY;
76         }
77
78         if (offset < 0) { // offset parameter
79 offset = 0;
80         }
81         while (offset > 0) {
82             if (iterator.hasNext()) {
83                 iterator.next();
84                 offset--;
85                 index++;
86             } else {
87                 return SKIP_BODY; // offset > length
88 }
89         }
90         if (iterator.hasNext()) {
91             doIterator(iterator);
92             return EVAL_BODY_AGAIN;
93         } else {
94             return SKIP_BODY;
95         }
96     }
97
98     public int doAfterBody() throws JspTagException {
99         BodyContent body = getBodyContent();
100         try {
101             body.writeOut(getPreviousOut());
102         } catch (IOException ioe) {
103             throw new JspTagException("IteratorTag: " + ioe.getMessage());
104         }
105         body.clearBody();
106
107         if (lengthValue > 0) {
108             if (iterator.hasNext()) {
109                 doIterator(iterator);
110                 return EVAL_BODY_AGAIN;
111             }
112         }
113         return SKIP_BODY;
114     }
115
116     public int doEndTag() {
117         return EVAL_PAGE;
118     }
119 }
120
Popular Tags