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19 package org.apache.cayenne.access.jdbc;
20
21 import java.util.HashMap  ;
22 import java.util.Iterator ;
23 import java.util.List ;
24 import java.util.Map ;
25
26 import org.apache.cayenne.ejbql.EJBQLBaseVisitor;
27 import org.apache.cayenne.ejbql.EJBQLException;
28 import org.apache.cayenne.ejbql.EJBQLExpression;
29 import org.apache.cayenne.ejbql.parser.EJBQLIdentificationVariable;
30 import org.apache.cayenne.ejbql.parser.EJBQLIdentifier;
31 import org.apache.cayenne.ejbql.parser.EJBQLInnerJoin;
32 import org.apache.cayenne.ejbql.parser.EJBQLPath;
33 import org.apache.cayenne.map.DbEntity;
34 import org.apache.cayenne.map.DbJoin;
35 import org.apache.cayenne.map.DbRelationship;
36 import org.apache.cayenne.map.ObjAttribute;
37 import org.apache.cayenne.map.ObjEntity;
38 import org.apache.cayenne.map.ObjRelationship;
39 import org.apache.cayenne.reflect.ClassDescriptor;
40
41
47 abstract class EJBQLPathTranslator extends EJBQLBaseVisitor {
48
49 private EJBQLTranslationContext context;
50 protected ObjEntity currentEntity;
51 private String lastPathComponent;
52 protected String lastAlias;
53 protected String idPath;
54 protected String joinMarker;
55 private String fullPath;
56 private EJBQLFromTranslator joinAppender;
57
58 EJBQLPathTranslator(EJBQLTranslationContext context) {
59 super(true);
60 this.context = context;
61 }
62
63 protected abstract void appendMultiColumnPath(EJBQLMultiColumnOperand operand);
64
65 public boolean visitPath(EJBQLPath expression, int finishedChildIndex) {
66
67 if (finishedChildIndex > 0) {
68
69 if (finishedChildIndex + 1 < expression.getChildrenCount()) {
70 processIntermediatePathComponent();
71 }
72 else {
73 processLastPathComponent();
74 }
75 }
76
77 return true;
78 }
79
80 public boolean visitIdentifier(EJBQLExpression expression) {
81 ClassDescriptor descriptor = context.getCompiledExpression().getEntityDescriptor(
82 expression.getText());
83 if (descriptor == null) {
84 throw new EJBQLException("Invalid identification variable: "
85 + expression.getText());
86 }
87
88 this.currentEntity = descriptor.getEntity();
89 this.idPath = expression.getText();
90 this.joinMarker = EJBQLFromTranslator.makeJoinTailMarker(idPath);
91 this.fullPath = idPath;
92 return true;
93 }
94
95 public boolean visitIdentificationVariable(EJBQLExpression expression) {
96
97 if (lastPathComponent != null) {
100 resolveJoin();
101 }
102
103 this.lastPathComponent = expression.getText();
104 return true;
105 }
106
107 private EJBQLFromTranslator getJoinAppender() {
108 if (joinAppender == null) {
109 joinAppender = new EJBQLFromTranslator(context);
110 }
111
112 return joinAppender;
113 }
114
115 private void resolveJoin() {
116
117 String newPath = idPath + '.' + lastPathComponent;
118 String oldPath = context.registerReusableJoin(idPath, lastPathComponent, newPath);
119
120 this.fullPath = fullPath + '.' + lastPathComponent;
121
122 if (oldPath != null) {
123 this.idPath = oldPath;
124 this.lastAlias = context.getTableAlias(oldPath, currentEntity
125 .getDbEntityName());
126 }
127 else {
128 EJBQLIdentifier id = new EJBQLIdentifier(-1);
130 id.setText(idPath);
131
132 EJBQLIdentificationVariable idVar = new EJBQLIdentificationVariable(-1);
133 idVar.setText(lastPathComponent);
134
135 EJBQLPath path = new EJBQLPath(-1);
136 path.jjtAddChild(id, 0);
137 path.jjtAddChild(idVar, 1);
138
139 EJBQLIdentifier joinId = new EJBQLIdentifier(-1);
140 joinId.setText(fullPath);
141
142 EJBQLInnerJoin join = new EJBQLInnerJoin(-1);
143 join.jjtAddChild(path, 0);
144 join.jjtAddChild(joinId, 1);
145
146 context.switchToMarker(joinMarker);
147
148 getJoinAppender().visitInnerJoin(join);
149 context.switchToMainBuffer();
150
151 this.idPath = newPath;
152 this.lastAlias = context.getTableAlias(fullPath, currentEntity
153 .getDbEntityName());
154 }
155 }
156
157 private void processIntermediatePathComponent() {
158 ObjRelationship relationship = (ObjRelationship) currentEntity
159 .getRelationship(lastPathComponent);
160 if (relationship == null) {
161 throw new EJBQLException("Unknown relationship '"
162 + lastPathComponent
163 + "' for entity '"
164 + currentEntity.getName()
165 + "'");
166 }
167
168 this.currentEntity = (ObjEntity) relationship.getTargetEntity();
169 }
170
171 private void processLastPathComponent() {
172
173 ObjAttribute attribute = (ObjAttribute) currentEntity
174 .getAttribute(lastPathComponent);
175
176 if (attribute != null) {
177 processTerminatingAttribute(attribute);
178 return;
179 }
180
181 ObjRelationship relationship = (ObjRelationship) currentEntity
182 .getRelationship(lastPathComponent);
183 if (relationship != null) {
184 processTerminatingRelationship(relationship);
185 return;
186 }
187
188 throw new IllegalStateException ("Invalid path component: " + lastPathComponent);
189 }
190
191 protected void processTerminatingAttribute(ObjAttribute attribute) {
192
193 DbEntity table = currentEntity.getDbEntity();
194 String alias = this.lastAlias != null ? lastAlias : context.getTableAlias(
195 idPath,
196 table.getFullyQualifiedName());
197 context.append(' ').append(alias).append('.').append(
198 attribute.getDbAttributeName());
199 }
200
201 private void processTerminatingRelationship(ObjRelationship relationship) {
202
203 if (relationship.isSourceIndependentFromTargetChange()) {
205 }
207 else {
208
210 DbRelationship dbRelationship = (DbRelationship) relationship
212 .getDbRelationships()
213 .get(0);
214 DbEntity table = (DbEntity) dbRelationship.getSourceEntity();
215
216 String alias = this.lastAlias != null ? lastAlias : context.getTableAlias(
217 idPath,
218 table.getFullyQualifiedName());
219
220 List joins = dbRelationship.getJoins();
221
222 if (joins.size() == 1) {
223 DbJoin join = (DbJoin) joins.get(0);
224 context
225 .append(' ')
226 .append(alias)
227 .append('.')
228 .append(join.getSourceName());
229 }
230 else {
231 Map multiColumnMatch = new HashMap (joins.size() + 2);
232
233 Iterator it = joins.iterator();
234 while (it.hasNext()) {
235 DbJoin join = (DbJoin) it.next();
236 String column = alias + "." + join.getSourceName();
237
238 multiColumnMatch.put(join.getTargetName(), column);
239 }
240
241 appendMultiColumnPath(EJBQLMultiColumnOperand.getPathOperand(
242 context,
243 multiColumnMatch));
244 }
245 }
246 }
247 }
248 |
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