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1
15 package org.josql.expressions;
16
17 import java.util.Map  ;
18 import java.util.List ;
19 import java.util.ArrayList ;
20 import java.util.Collection ;
21 import java.util.Iterator ;
22
23 import com.gentlyweb.utils.Getter;
24
25 import org.josql.Query;
26 import org.josql.QueryResults;
27 import org.josql.QueryExecutionException;
28 import org.josql.QueryParseException;
29
30 import org.josql.internal.Utilities;
31
32 import org.josql.events.*;
33
34 public class SubQueryExpression extends ValueExpression implements BindVariableChangedListener,
35 SaveValueChangedListener
36 {
37
38 private Query q = null;
39 private boolean inited = false;
40 private String acc = null;
41 private Getter get = null;
42 private boolean nullQuery = false;
43
44 public SubQueryExpression (Query q)
45 {
46
47 this.q = q;
48
49 this.q.addBindVariableChangedListener (this);
50 this.q.addSaveValueChangedListener (this);
51
52 }
53
54 public void bindVariableChanged (BindVariableChangedEvent ev)
55 {
56
57 if (this.q.getFrom () instanceof BindVariable)
58 {
59
60 BindVariable bv = (BindVariable) this.q.getFrom ();
61
62 if (bv.getName ().equalsIgnoreCase (ev.getName ()))
63 {
64
65 this.inited = false;
66
67 }
68
69 }
70
71 }
72
73 public void saveValueChanged (SaveValueChangedEvent ev)
74 {
75
76 if (this.q.getFrom () instanceof SaveValue)
77 {
78
79 SaveValue sv = (SaveValue) this.q.getFrom ();
80
81 if (sv.getName ().equalsIgnoreCase (ev.getName ()))
82 {
83
84 this.inited = false;
85
86 }
87
88 }
89
90 }
91
92 public Getter getGetter ()
93 {
94
95 return this.get;
96
97 }
98
99 public void setAccessor (String acc)
100 {
101
102 this.acc = acc;
103
104 }
105
106 public String getAccessor ()
107 {
108
109 return this.acc;
110
111 }
112
113 public Query getQuery ()
114 {
115
116 return this.q;
117
118 }
119
120 public boolean hasFixedResult (Query q)
121 {
122
123 return false;
124
125 }
126
127 public Class getExpectedReturnType (Query q)
128 throws QueryParseException
129 {
130
131 if (this.get != null)
132 {
133
134 return this.get.getType ();
135
136 }
137
138 return List .class;
139
140 }
141
142 public void init (Query q)
143 throws QueryParseException
144 {
145
146 if (this.acc != null)
148 {
149
150 try
151 {
152
153 this.get = new Getter (this.acc,
154 ArrayList .class);
155
156 } catch (Exception e) {
157
158 throw new QueryParseException ("Sub-query: " +
159 this +
160 " has accessor: " +
161 this.acc +
162 " however no valid accessor has been found in return type: " +
163 ArrayList .class.getName (),
164 e);
165
166 }
167
168 }
169
170 }
171
172 public boolean isTrue (Object o,
173 Query q)
174 throws QueryExecutionException
175 {
176
177 List l = (List ) this.getValue (o,
178 q);
179
180 return l.size () > 0;
181
182 }
183
184 private void innerInit (Object o,
185 Query q)
186 throws QueryExecutionException
187 {
188
189 Object obj = null;
190
191 Expression from = this.q.getFrom ();
192
193 if (from instanceof ConstantExpression)
194 {
195
196 String g = (String ) from.getValue (null,
198 this.q);
199
200 if (!g.equalsIgnoreCase ("null"))
202 {
203
204 Accessor acc = new Accessor ();
205
206 acc.setAccessor (g);
207
208 this.q.setFrom (acc);
209
210 try
211 {
212
213 acc.init (q);
215
216 } catch (Exception e) {
217
218 throw new QueryExecutionException ("Unable to init accessor: " +
219 g +
220 " from class: " +
221 o.getClass () +
222 " for FROM clause, for sub-query: \"" +
223 this.q +
224 "\"",
225 e);
226
227 }
228
229 obj = this.q.getFrom ().getValue (o,
231 this.q);
232
233 } else {
234
235 List l = new ArrayList ();
237 l.add (new Object ());
238
239 obj = l;
240
241 this.nullQuery = true;
242
243 }
244
245 }
246
247 if (from instanceof Accessor)
248 {
249
250 obj = this.q.getFrom ().getValue (o,
252 this.q);
253
254 }
255
256 if (from instanceof Function)
257 {
258
259 try
260 {
261
262 from.init (this.q);
263
264 } catch (Exception e) {
265
266 throw new QueryExecutionException ("Unable to init FROM clause: " +
267 from +
268 " for sub-query: " +
269 this.q,
270 e);
271
272 }
273
274 obj = this.q.getFrom ().getValue (o,
277 q);
278
279 }
280
281 if (from instanceof SaveValue)
282 {
283
284 obj = from.getValue (o,
285 q.getTopLevelQuery ());
286
287 }
288
289 if (from instanceof BindVariable)
290 {
291
292 try
294 {
295
296 from.init (q.getTopLevelQuery ());
297
298 } catch (Exception e) {
299
300 throw new QueryExecutionException ("Unable to init FROM clause: " +
301 from +
302 " for sub-query: " +
303 this.q,
304 e);
305
306 }
307
308 obj = from.getValue (o,
309 q.getTopLevelQuery ());
310
311 }
312
313 if (obj == null)
314 {
315
316 return;
317
318 }
319
320 if (!(obj instanceof Collection ))
322 {
323
324 throw new QueryExecutionException ("Expected FROM clause: " +
325 this.q.getFrom () +
326 " for sub-query: " +
327 this.q +
328 " to evaluate to an instance of: " +
329 Collection .class.getName () +
330 ", instead evaluates to: " +
331 obj.getClass ().getName () +
332 " using from expression: " +
333 from);
334
335 }
336
337 Collection col = (Collection ) obj;
338
339 Iterator iter = col.iterator ();
341
342 if (!iter.hasNext ())
343 {
344
345 return;
346
347 }
348
349 Object io = iter.next ();
350
351 if (io == null)
353 {
354
355 while (iter.hasNext ())
358 {
359
360 io = iter.next ();
361
362 if (io != null)
363 {
364
365 break;
366
367 }
368
369 }
370
371 }
372
373 if (io == null)
374 {
375
376 return;
378
379 }
380
381 this.q.setFromObjectClass (io.getClass ());
382
383 try
384 {
385
386 this.q.init ();
387
388 } catch (Exception e) {
389
390 throw new QueryExecutionException ("Unable to init sub-query: " +
391 this.q +
392 " with class: " +
393 io.getClass ().getName (),
394 e);
395
396 }
397
398 this.inited = true;
399
400 }
401
402 private List innerGetValue (Object o,
403 Query q)
404 throws QueryExecutionException
405 {
406
407 if (this.nullQuery)
408 {
409
410 return Query.nullQueryList;
411
412 }
413
414 Object obj = null;
415
416 try
417 {
418
419 obj = this.q.getFrom ().getValue (o,
420 this.q.getTopLevelQuery ());
421
422 } catch (Exception e) {
423
424 throw new QueryExecutionException ("Unable to evaluate FROM clause accessor: " +
425 this.q.getFrom () +
426 " for sub-query: " +
427 this.q,
428 e);
429
430 }
431
432 if (obj == null)
433 {
434
435 return new ArrayList ();
436
437 }
438
439 if (!(obj instanceof Collection ))
440 {
441
442 throw new QueryExecutionException ("Evaluation of FROM clause for sub-query: " +
443 this.q +
444 " returns an instance of: " +
445 obj.getClass ().getName () +
446 " however only sub-classes of: " +
447 Collection .class.getName () +
448 " are supported.");
449
450 }
451
452 List l = null;
453
454 if (obj instanceof List )
456 {
457
458 l = (List ) obj;
459
460 } else {
461
462 l = new ArrayList ((Collection ) obj);
463
464 }
465
466 return l;
467
468 }
469
470 public Object evaluate (Object o,
471 Query q)
472 throws QueryExecutionException
473 {
474
475 this.q.setParent (q);
476
477 if (!this.inited)
478 {
479
480 this.innerInit (o,
481 q);
482
483 }
484
485 if (this.inited)
486 {
487
488 List l = this.innerGetValue (o,
489 q);
490
491 QueryResults qr = this.q.execute (l);
492
493 if (this.get != null)
494 {
495
496 try
497 {
498
499 return this.get.getValue (qr.getResults ());
500
501 } catch (Exception e) {
502
503 throw new QueryExecutionException ("Unable to get value for accessor: " +
504 this.acc +
505 " from return type: " +
506 ArrayList .class.getName () +
507 " after execution of sub-query: " +
508 this,
509 e);
510
511 }
512
513 }
514
515 return qr.getResults ();
516
517 }
518
519 return new ArrayList ();
520
521 }
522
523 public String toString ()
524 {
525
526 return "(" + this.q.toString () + ")";
527
528 }
529
530 }
531
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