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22
23 package org.xquark.mediator.plan;
24
25 import java.util.ArrayList  ;
26
27 import org.xml.sax.ContentHandler ;
28 import org.xquark.mediator.DOMUtils.*;
29 import org.xquark.mediator.runtime.MediatorException;
30 import org.xquark.schema.validation.PSVInfoSetProvider;
31 import org.xquark.xml.xdbc.XMLDBCException;
32 import org.xquark.xquery.parser.Step;
33 import org.xquark.xquery.parser.XQueryException;
34 import org.xquark.xquery.parser.XQueryExpression;
35 import org.xquark.xquery.typing.QAtomicSerializer;
36
37 public abstract class ResultSet {
38 private static final String RCSRevision = "$Revision: 1.16 $";
42 private static final String RCSName = "$Name: $";
43 protected TypedDOMReader dom2sax = null;
47 protected QAtomicSerializer ser = null;
48
49 protected XQueryExpression expression = null;
50 protected Operator operator;
51 private boolean first_time = true;
52 private boolean finished_when_empty = false;
53
54 protected BufferTuple buftuples = null;
55 private Tuple cur_tuple = null;
56 private Tuple next_tuple = null;
57 protected ArrayList paths;
58
59 protected DynamicContext context = null;
60
61
67 public ResultSet(Operator operator, DynamicContext context) {
68 this.operator = operator;
69 this.context = context;
70 dom2sax = new TypedDOMReader();
71 ser = new QAtomicSerializer();
72 dom2sax.setQAtomicSerializer(ser);
73 init(operator);
74 }
75
76 public void init(Operator operator) {
77 if (operator != null) {
78 expression = operator.getExpression();
79 paths = operator.getPaths();
80 buftuples = new BufferTuple(paths, operator.getIdSize());
81 buftuples.setIndexesSpec(operator.getIndexesSpec());
82 }
83 }
84
85 protected void generateTuple() throws MediatorException {
86 if (!buftuples.isEmpty())
88 return;
89
90 evaluate(!operator.isLet());
92 }
93
94
100 protected abstract void evaluate(boolean non_blocking) throws MediatorException;
101
102 protected void setFinishedWhenEmpty() throws MediatorException {
103 this.finished_when_empty = true;
104 }
105
106 public Operator getOperator() {
107 return operator;
108 }
109
110 public SortedKeyMap getIndex(int index) {
111 return buftuples.getIndex(index);
112 }
113
114
119 public Tuple next() throws MediatorException {
120 if (next_tuple != null) {
121 cur_tuple = next_tuple;
122 next_tuple = null;
123 return cur_tuple;
124 }
125
126 if (first_time) {
127 hasNext();
128 if (buftuples.isEmpty())
129 throw new MediatorException("No more results");
130 }
131
132 if (buftuples.isEmpty()) {
134 generateTuple();
135 if (buftuples.isEmpty())
136 throw new MediatorException("No more results");
137 }
138
139 if (!buftuples.isEmpty()) {
140 cur_tuple = (Tuple) buftuples.remove(0);
141 return cur_tuple;
142 }
143
144 return cur_tuple;
145 }
146
147
151 public boolean hasNext() throws MediatorException {
152
153 if (next_tuple != null)
154 return true;
155
156 if (first_time) {
157 generateTuple();
158 first_time = false;
159 }
160
161 if ((finished_when_empty) && (buftuples == null || buftuples.isEmpty()))
162 return false;
163
164 if (buftuples.isEmpty())
165 generateTuple();
166
167 return (!((finished_when_empty) && (buftuples == null || buftuples.isEmpty())));
168 }
169
170
179 public void close() throws MediatorException {
180 buftuples = null;
181 }
182
183
191 public String fetch(String path, int nodeAccessor, String loopID, PSVInfoSetProvider psvisp) throws XMLDBCException {
192 String alias = path;
193 while ((alias = operator.getPlan().getAlias(path)) != null) {
194 path = alias;
195 }
196 int pos = buftuples.getPos(path);
198 if (pos != -1)
199 return cur_tuple.makeStringPath(pos, ser);
200 switch (nodeAccessor) {
201 case Step.CHILD_TEXT :
202 pos = buftuples.getPos(path + "/child::text()");
204 break;
205
209 case Step.CHILD_NODE :
210 pos = buftuples.getPos(path + "/child::node()");
212 break;
213
229 case Step.SELF_TEXT :
230 pos = buftuples.getPos(path + "/self::text()");
232 break;
233 case Step.SELF_NODE :
234 pos = buftuples.getPos(path + "/self::node()");
236 break;
237 }
238 if (pos == -1)
239 pos = buftuples.getPos(path);
240 if (pos == -1)
241 throw new XMLDBCException("No column " + path + " in tuple.");
242 return cur_tuple.makeStringPath(pos, ser);
243 }
245
246
253 public void generate(ContentHandler handler, String path, int nodeAccessor, String loopID, PSVInfoSetProvider psvisp) throws XMLDBCException {
254 String alias = path;
255 while ((alias = operator.getPlan().getAlias(path)) != null) {
256 path = alias;
257 }
258 int pos = -1;
260 switch (nodeAccessor) {
261 case Step.CHILD_TEXT :
262 pos = buftuples.getPos(path + "/child::text()");
264 break;
265
269 case Step.CHILD_NODE :
270 pos = buftuples.getPos(path + "/child::node()");
272 break;
273
289 case Step.SELF_TEXT :
290 pos = buftuples.getPos(path + "/self::text()");
292 break;
293 case Step.SELF_NODE :
294 pos = buftuples.getPos(path + "/self::node()");
296 break;
297 }
298 if (pos == -1)
299 pos = buftuples.getPos(path);
300 if (pos == -1)
301 throw new XMLDBCException("No column " + path + " in tuple.");
302 try {
303 dom2sax.setPSVInfoSetProvider(psvisp);
304 cur_tuple.makeEventPath(dom2sax, handler, pos);
305 } catch (XQueryException e) {
306 throw new XMLDBCException(e.getMessage());
307 }
308 }
309
310
315 public void getIdentifiers(Object [] identifiers) {
316 if (cur_tuple == null)
317 return;
318 cur_tuple.getIdentifiers(identifiers);
319 }
320
321
327 public void getNextIdentifiers(Object [] identifiers) throws MediatorException {
328 if (next_tuple != null) {
333 next_tuple.getIdentifiers(identifiers);
334 return;
335 }
336 if (!hasNext()) {
337 next_tuple = null;
338 return;
339 }
340 Tuple old_tuple = cur_tuple;
341 next();
342 next_tuple = cur_tuple;
343 next_tuple.getIdentifiers(identifiers);
344 cur_tuple = old_tuple;
345 }
346 }
347 |
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