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Java > Open Source Codes > org > objectstyle > cayenne > query > NamedQuery


1 /* ====================================================================
2  *
3  * The ObjectStyle Group Software License, version 1.1
4  * ObjectStyle Group - http://objectstyle.org/
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7  * of the software. All rights reserved.
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56 package org.objectstyle.cayenne.query;
57
58 import java.util.Collections JavaDoc;
59 import java.util.Map JavaDoc;
60
61 import org.apache.commons.lang.builder.ToStringBuilder;
62 import org.objectstyle.cayenne.CayenneRuntimeException;
63 import org.objectstyle.cayenne.map.EntityResolver;
64 import org.objectstyle.cayenne.util.Util;
65
66 /**
67  * A query that is a reference to a named parameterized query stored in the mapping. The
68  * actual query is resolved during execution.
69  *
70  * @since 1.2
71  * @author Andrus Adamchik
72  */

73 public class NamedQuery implements QueryExecutionPlan {
74
75     protected String JavaDoc name;
76     protected Map JavaDoc parameters;
77
78     public NamedQuery(String JavaDoc name) {
79         this(name, null);
80     }
81
82     public NamedQuery(String JavaDoc name, Map JavaDoc parameters) {
83         this.name = name;
84         this.parameters = parameters;
85     }
86
87     /**
88      * Creates NamedQuery with parameters passed as two matching arrays of keys and values.
89      */

90     public NamedQuery(String JavaDoc name, String JavaDoc[] keys, Object JavaDoc[] values) {
91         this.name = name;
92         this.parameters = Util.toMap(keys, values);
93     }
94
95     public String JavaDoc getName() {
96         return name;
97     }
98
99     public void setName(String JavaDoc name) {
100         this.name = name;
101     }
102
103     /**
104      * A callback method invoked by Cayenne during the first phase of execution. Allows
105      * query to resolve itself. For example a query can be a "proxy" for another query
106      * stored by name in the DataMap. In this method such query would find the actual
107      * mapped query and return it to the caller for execution.
108      */

109     public Query resolve(EntityResolver resolver) {
110         Query substituteQuery = substituteQuery(resolver);
111
112         if (substituteQuery == null) {
113             throw new CayenneRuntimeException("Can't find named query for name '"
114                     + getName()
115                     + "'");
116         }
117
118         return substituteQuery;
119     }
120
121     /**
122      * Resolves a real query for the name and delegates further execution to this query.
123      */

124     public void route(QueryRouter router, EntityResolver resolver) {
125         throw new CayenneRuntimeException(this
126                 + " doesn't support its own routing. "
127                 + "It should've been delegated to another "
128                 + "query during resolution phase.");
129     }
130
131     /**
132      * Throws an exception as query execution is expected to be delegated to a resolved
133      * named query during routing phase.
134      */

135     public SQLAction createSQLAction(SQLActionVisitor visitor) {
136         throw new CayenneRuntimeException(this
137                 + " doesn't support its own sql actions. "
138                 + "It should've been delegated to another "
139                 + "query during resolution phase.");
140     }
141
142     /**
143      * Locates and initializes a substitution query.
144      */

145     protected Query substituteQuery(EntityResolver resolver) {
146         Query query = resolver.lookupQuery(getName());
147
148         if(query instanceof ParameterizedQuery) {
149             // must process the query even if we have no parameters set
150
Map JavaDoc parameters = (this.parameters != null) ? this.parameters : Collections.EMPTY_MAP;
151             query = ((ParameterizedQuery) query).createQuery(parameters);
152         }
153
154         return query;
155     }
156
157     public String JavaDoc toString() {
158         return new ToStringBuilder(this).append("name", name).toString();
159     }
160 }
161
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