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1
28
29 package com.caucho.jstl.el;
30
31 import com.caucho.el.Expr;
32 import com.caucho.jsp.PageContextImpl;
33 import com.caucho.util.CharBuffer;
34 import com.caucho.util.EnumIterator;
35 import com.caucho.util.L10N;
36 import com.caucho.util.NullIterator;
37
38 import javax.el.ELContext;
39 import javax.servlet.jsp.JspException  ;
40 import javax.servlet.jsp.JspTagException ;
41 import javax.servlet.jsp.jstl.core.LoopTag;
42 import javax.servlet.jsp.jstl.core.LoopTagStatus;
43 import javax.servlet.jsp.tagext.IterationTag ;
44 import javax.servlet.jsp.tagext.TagSupport ;
45 import java.lang.reflect.Array ;
46 import java.util.Collection ;
47 import java.util.Enumeration ;
48 import java.util.Iterator ;
49 import java.util.Map ;
50
51 public class ForEachTag extends TagSupport
52 implements IterationTag , LoopTag, LoopTagStatus {
53 private static L10N L = new L10N(ForEachTag.class);
54
55 protected Expr _itemsExpr;
56
57 protected Expr _beginExpr;
58 protected Expr _endExpr;
59 protected Expr _stepExpr;
60
61 protected String _var;
62 protected String _varStatus;
63
64 protected Iterator _iterator;
66
67 protected int _begin;
68 protected int _end;
69 protected int _step;
70
71 protected Object _initialVar;
72 protected Object _current;
73 protected int _index;
74 protected int _count;
75
76
79 public void setItems(Expr items)
80 {
81 _itemsExpr = items;
82 }
83
84
87 public void setBegin(Expr begin)
88 {
89 _beginExpr = begin;
90 }
91
92
95 public void setEnd(Expr end)
96 {
97 _endExpr = end;
98 }
99
100
103 public void setStep(Expr step)
104 {
105 _stepExpr = step;
106 }
107
108
111 public void setVar(String var)
112 {
113 _var = var;
114 }
115
116
119 public void setVarStatus(String var)
120 {
121 _varStatus = var;
122 }
123
124
127 public int doStartTag()
128 throws JspException
129 {
130 try {
131 _iterator = null;
132 _index = 0;
133 _count = 0;
134
135 PageContextImpl pageContext = (PageContextImpl) this.pageContext;
136 ELContext env = pageContext.getELContext();
137
138 if (_beginExpr != null)
139 _begin = (int) _beginExpr.evalLong(env);
140 else
141 _begin = -1;
142
143 if (_endExpr != null)
144 _end = (int) _endExpr.evalLong(env);
145 else
146 _end = Integer.MAX_VALUE;
147
148 if (_stepExpr != null)
149 _step = (int) _stepExpr.evalLong(env);
150 else
151 _step = 0;
152
153 Object items = null;
154
155 if (_itemsExpr != null) {
156 items = _itemsExpr.evalObject(env);
157
158 _iterator = getIterator(items);
159
160 while (_index < _begin && _iterator.hasNext()) {
161 _index++;
162 _iterator.next();
163 }
164 }
165 else if (_beginExpr == null)
166 throw new JspException (L.l("c:forEach must specify `items' or `begin'"));
167 else if (_endExpr == null)
168 throw new JspException (L.l("c:forEach must specify `items' or `begin'"));
169 else {
170 _iterator = new RangeIterator(_begin, _end);
171 _end = -1;
172 }
173
174 if (_varStatus != null)
175 pageContext.setAttribute(_varStatus, this);
176
177 if (_var != null)
178 _initialVar = pageContext.getAttribute(_var);
179
180 return doAfterBody();
181 } catch (Exception e) {
182 throw new JspException (e);
183 }
184 }
185
186 public int doAfterBody() throws JspException
187 {
188 if (_iterator == null) {
189 if (_var != null)
190 pageContext.setAttribute(_var, _initialVar);
191
192 return SKIP_BODY;
193 }
194 else if (_iterator.hasNext()) {
195 int stepCount;
196
197 if (_step <= 0 || _count == 0)
198 stepCount = 1;
199 else
200 stepCount = _step;
201
202 for (; stepCount > 0; stepCount--) {
203 if (! _iterator.hasNext()) {
204 if (_var != null)
205 pageContext.setAttribute(_var, _initialVar);
206
207 return SKIP_BODY;
208 }
209
210 _index++;
211 _current = _iterator.next();
212 }
213
214 _count++;
215
216 if (_var != null)
217 pageContext.setAttribute(_var, _current);
218
219 if (_index - 1 <= _end || _end < 0)
220 return EVAL_BODY_AGAIN;
221 else {
222 if (_var != null)
223 pageContext.setAttribute(_var, _initialVar);
224
225 return SKIP_BODY;
226 }
227 }
228 else {
229 if (_var != null)
230 pageContext.setAttribute(_var, _initialVar);
231
232 return SKIP_BODY;
233 }
234 }
235
236
238
241 public LoopTagStatus getLoopStatus()
242 {
243 return this;
244 }
245
246
247
249
252 public Object getCurrent()
253 {
254 return _current;
255 }
256
257
260 public int getIndex()
261 {
262 return _index - 1;
263 }
264
265
268 public int getCount()
269 {
270 return _count;
271 }
272
273
276 public boolean isFirst()
277 {
278 return _count == 1;
279 }
280
281
284 public boolean isLast()
285 {
286 if (_iterator == null || ! _iterator.hasNext())
287 return true;
288 else if (_step > 0 && _step + _index > _end)
289 return true;
290 else
291 return false;
292 }
293
294
297 public Integer getBegin()
298 {
299 if (_beginExpr != null && _itemsExpr != null)
300 return new Integer (_begin);
301 else
302 return null;
303 }
304
305
308 public Integer getEnd()
309 {
310 if (_endExpr != null && _itemsExpr != null)
311 return new Integer (_end);
312 else
313 return null;
314 }
315
316
319 public Integer getStep()
320 {
321 if (_stepExpr != null)
322 return new Integer (_step);
323 else
324 return null;
325 }
326
327 public static Iterator getIterator(Object items)
328 throws JspTagException
329 {
330 if (items == null)
331 return NullIterator.create();
332 else if (items instanceof Map )
333 return ((Map ) items).entrySet().iterator();
334 else if (items instanceof Collection )
335 return ((Collection ) items).iterator();
336 else if (items.getClass().isArray())
337 return new ArrayIterator(items);
338 else if (items instanceof Iterator)
339 return (Iterator) items;
340 else if (items instanceof Enumeration )
341 return new EnumIterator((Enumeration ) items);
342 else if (items instanceof String )
343 return new StringIterator((String ) items);
344 else
345 throw new JspTagException (L.l("unknown items value `{0}'", items));
346 }
347
348 public static class ArrayIterator implements Iterator {
349 private Object array;
350 private int index;
351 private int length;
352
353 ArrayIterator(Object array)
354 {
355 this.array = array;
356 this.length = Array.getLength(array);
357 }
358
359 public boolean hasNext()
360 {
361 return index < length;
362 }
363
364 public Object next()
365 {
366 if (index < length)
367 return Array.get(array, index++);
368 else
369 return null;
370 }
371
372 public void remove()
373 {
374 throw new UnsupportedOperationException ();
375 }
376 }
377
378 public static class StringIterator implements Iterator {
379 private String _value;
380 private int _length;
381 private int _i;
382 private CharBuffer _cb = new CharBuffer();
383
384 StringIterator(String value)
385 {
386 _value = value;
387 _length = value.length();
388 }
389
390 public boolean hasNext()
391 {
392 return _i < _length;
393 }
394
395 public Object next()
396 {
397 _cb.clear();
398
399 char ch = 0;
400 for (; _i < _length && (ch = _value.charAt(_i)) != ','; _i++)
401 _cb.append(ch);
402
403 _i++;
404
405 return _cb.toString();
406 }
407
408 public void remove()
409 {
410 throw new UnsupportedOperationException ();
411 }
412 }
413
414 public static class RangeIterator implements Iterator {
415 private int _end;
416 private int _i;
417
418 RangeIterator(int begin, int end)
419 {
420 _i = begin;
421 _end = end;
422 }
423
424 public boolean hasNext()
425 {
426 return _i <= _end;
427 }
428
429 public Object next()
430 {
431 if (_i <= _end)
432 return new Integer (_i++);
433 else
434 return null;
435 }
436
437 public void remove()
438 {
439 throw new UnsupportedOperationException ();
440 }
441 }
442 }
443 |
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