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1
23
24 package javax.servlet.jsp.jstl.core;
25
26 import java.util.Iterator  ;
27 import java.util.Collection ;
28 import java.util.Enumeration ;
29 import java.util.Map ;
30 import java.util.StringTokenizer ;
31
32 import javax.el.ELContext;
33 import javax.el.ELException;
34 import javax.el.ValueExpression;
35
36 import javax.servlet.jsp.JspTagException ;
37
38 import org.apache.taglibs.standard.resources.Resources;
39
40
44 public final class IteratedExpression {
45
46 private static final long serialVersionUID = 1L;
47 protected final ValueExpression orig;
48 protected final String delims;
49
50 private Object base;
51 private int index;
52 private Iterator iter;
53
54 public IteratedExpression(ValueExpression orig, String delims) {
55 this.orig = orig;
56 this.delims = delims;
57 }
58
59
64 public Object getItem(ELContext context, int i) {
65
66 if (base == null) {
67 base = orig.getValue(context);
68 if (base == null) {
69 return null;
70 }
71 iter = toIterator(base);
72 index = 0;
73 }
74 if (index > i) {
75 iter = toIterator(base);
77 index = 0;
78 }
79 while (iter.hasNext()) {
80 Object item = iter.next();
81 if (index++ == i) {
82 return item;
83 }
84 }
85 return null;
86 }
87
88 public ValueExpression getValueExpression() {
89 return orig;
90 }
91
92 private Iterator toIterator(final Object obj) {
93
94 Iterator iter;
95 if (obj instanceof String ) {
96 iter = toIterator(new StringTokenizer ((String )obj, delims));
97 }
98 else if (obj instanceof Iterator ) {
99 iter = (Iterator )obj;
100 }
101 else if (obj instanceof Collection ) {
102 iter = toIterator(((Collection ) obj).iterator());
103 }
104 else if (obj instanceof Enumeration ) {
105 iter = toIterator((Enumeration )obj);
106 }
107 else if (obj instanceof Map ) {
108 iter = ((Map )obj).entrySet().iterator();
109 } else {
110 throw new ELException(Resources.getMessage("FOREACH_BAD_ITEMS"));
111 }
112 return iter;
113 }
114
115 private Iterator toIterator(final Enumeration obj) {
116 return new Iterator () {
117 public boolean hasNext() {
118 return obj.hasMoreElements();
119 }
120 public Object next() {
121 return obj.nextElement();
122 }
123 public void remove() {}
124 };
125 }
126 }
127
128 |
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