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19 package org.apache.cayenne.access.jdbc;
20
21 import java.util.Iterator  ;
22
23 import org.apache.cayenne.ejbql.EJBQLBaseVisitor;
24 import org.apache.cayenne.ejbql.EJBQLException;
25 import org.apache.cayenne.ejbql.EJBQLExpression;
26 import org.apache.cayenne.ejbql.parser.EJBQLFromItem;
27 import org.apache.cayenne.ejbql.parser.EJBQLJoin;
28 import org.apache.cayenne.map.DbJoin;
29 import org.apache.cayenne.map.DbRelationship;
30 import org.apache.cayenne.map.ObjRelationship;
31 import org.apache.cayenne.reflect.ClassDescriptor;
32
33
37 class EJBQLFromTranslator extends EJBQLBaseVisitor {
38
39 private EJBQLTranslationContext context;
40 private String lastId;
41
42 static String makeJoinTailMarker(String id) {
43 return "FROM_TAIL" + id;
44 }
45
46 EJBQLFromTranslator(EJBQLTranslationContext context) {
47 super(true);
48 this.context = context;
49 }
50
51 public boolean visitFrom(EJBQLExpression expression, int finishedChildIndex) {
52 if (finishedChildIndex + 1 == expression.getChildrenCount()) {
53 if (lastId != null) {
54 context.markCurrentPosition(makeJoinTailMarker(lastId));
55 }
56 }
57
58 return true;
59 }
60
61 public boolean visitFromItem(EJBQLFromItem expression) {
62
63 String id = expression.getId();
64
65 if (lastId != null) {
66 context.append(',');
67 context.markCurrentPosition(makeJoinTailMarker(lastId));
68 }
69
70 this.lastId = id;
71 appendTable(id);
72 return false;
73 }
74
75 public boolean visitInnerFetchJoin(EJBQLJoin join) {
76 return visitInnerJoin(join);
78 }
79
80 public boolean visitInnerJoin(EJBQLJoin join) {
81 appendJoin(join, "INNER JOIN");
82 return false;
83 }
84
85 public boolean visitOuterFetchJoin(EJBQLJoin join) {
86 return visitOuterJoin(join);
88 }
89
90 public boolean visitOuterJoin(EJBQLJoin join) {
91 appendJoin(join, "LEFT OUTER JOIN");
92 return false;
93 }
94
95 private void appendJoin(EJBQLJoin join, String semantics) {
96
97 String rhsId = join.getRightHandSideId();
98
99 ObjRelationship joinRelationship = context
100 .getCompiledExpression()
101 .getIncomingRelationship(rhsId);
102 if (joinRelationship == null) {
103 throw new EJBQLException("No join configured for id " + rhsId);
104 }
105
106 DbRelationship incomingDB = (DbRelationship) joinRelationship
108 .getDbRelationships()
109 .get(0);
110
111 String lhsId = join.getLeftHandSideId();
112 String sourceAlias = context.getTableAlias(lhsId, incomingDB
113 .getSourceEntity()
114 .getName());
115
116 context.append(" ").append(semantics);
117 String targetAlias = appendTable(rhsId);
118 context.append(" ON (");
119
120 Iterator it = incomingDB.getJoins().iterator();
121 if (it.hasNext()) {
122 DbJoin dbJoin = (DbJoin) it.next();
123 context
124 .append(sourceAlias)
125 .append('.')
126 .append(dbJoin.getSourceName())
127 .append(" = ")
128 .append(targetAlias)
129 .append('.')
130 .append(dbJoin.getTargetName());
131 }
132
133 while (it.hasNext()) {
134 context.append(", ");
135 DbJoin dbJoin = (DbJoin) it.next();
136 context
137 .append(sourceAlias)
138 .append('.')
139 .append(dbJoin.getSourceName())
140 .append(" = ")
141 .append(targetAlias)
142 .append('.')
143 .append(dbJoin.getTargetName());
144 }
145
146 context.append(")");
147 }
148
149 private String appendTable(String id) {
150 ClassDescriptor descriptor = context.getCompiledExpression().getEntityDescriptor(
151 id);
152
153 String tableName = descriptor.getEntity().getDbEntity().getFullyQualifiedName();
154 String alias = context.getTableAlias(id, tableName);
155
156 context.append(' ').append(tableName).append(' ').append(alias);
159 return alias;
160 }
161 }
162 |
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