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19 package org.apache.cayenne.access.jdbc;
20
21 import org.apache.cayenne.ejbql.EJBQLBaseVisitor;
22 import org.apache.cayenne.ejbql.EJBQLExpression;
23
24 /**
25  * A translator of EJBQL select statements into SQL.
26  *
27  * @since 3.0
28  * @author Andrus Adamchik
29  */
30 class EJBQLSelectTranslator extends EJBQLBaseVisitor {
31
32     private EJBQLTranslationContext context;
33
34     EJBQLSelectTranslator(EJBQLTranslationContext context) {
35         this.context = context;
36     }
37
38     EJBQLTranslationContext getContext() {
39         return context;
40     }
41
42     public boolean visitDistinct(EJBQLExpression expression) {
43         context.append(" DISTINCT");
44         return true;
45     }
46
47     public boolean visitFrom(EJBQLExpression expression, int finishedChildIndex) {
48         context.append(" FROM");
49         expression.visit(new EJBQLFromTranslator(context));
50         return false;
51     }
52
53     public boolean visitOrderBy(EJBQLExpression expression) {
54         context.append(" ORDER BY");
55         expression.visit(new EJBQLOrderByTranslator(context));
56         return false;
57     }
58
59     public boolean visitSelect(EJBQLExpression expression) {
60         context.append("SELECT");
61         return true;
62     }
63
64     public boolean visitSelectExpressions(EJBQLExpression expression) {
65         expression.visit(new EJBQLSelectColumnsTranslator(context));
66         return false;
67     }
68
69     public boolean visitWhere(EJBQLExpression expression) {
70         context.append(" WHERE");
71         expression.visit(new EJBQLConditionTranslator(context));
72         return false;
73     }
74 }
75
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