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Java > Open Source Codes > org > objectstyle > cayenne > access > trans > UpdateTranslator


1 /* ====================================================================
2  *
3  * The ObjectStyle Group Software License, version 1.1
4  * ObjectStyle Group - http://objectstyle.org/
5  *
6  * Copyright (c) 2002-2005, Andrei (Andrus) Adamchik and individual authors
7  * of the software. All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
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13  * 1. Redistributions of source code must retain the above copyright
14  * notice, this list of conditions and the following disclaimer.
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17  * notice, this list of conditions and the following disclaimer in
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21  * 3. The end-user documentation included with the redistribution, if any,
22  * must include the following acknowlegement:
23  * "This product includes software developed by independent contributors
24  * and hosted on ObjectStyle Group web site (http://objectstyle.org/)."
25  * Alternately, this acknowlegement may appear in the software itself,
26  * if and wherever such third-party acknowlegements normally appear.
27  *
28  * 4. The names "ObjectStyle Group" and "Cayenne" must not be used to endorse
29  * or promote products derived from this software without prior written
30  * permission. For written permission, email
31  * "andrus at objectstyle dot org".
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33  * 5. Products derived from this software may not be called "ObjectStyle"
34  * or "Cayenne", nor may "ObjectStyle" or "Cayenne" appear in their
35  * names without prior written permission.
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37  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
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43  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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45  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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48  * SUCH DAMAGE.
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51  * This software consists of voluntary contributions made by many
52  * individuals and hosted on ObjectStyle Group web site. For more
53  * information on the ObjectStyle Group, please see
54  * <http://objectstyle.org/>.
55  */
56 package org.objectstyle.cayenne.access.trans;
57
58 import java.util.Iterator JavaDoc;
59 import java.util.Map JavaDoc;
60
61 import org.objectstyle.cayenne.CayenneRuntimeException;
62 import org.objectstyle.cayenne.map.DbAttribute;
63 import org.objectstyle.cayenne.map.DbEntity;
64 import org.objectstyle.cayenne.map.DbRelationship;
65 import org.objectstyle.cayenne.query.UpdateQuery;
66
67 /** Class implements default translation mechanism of
68   * org.objectstyle.cayenne.query.UpdateQuery
69   * objects to SQL UPDATE statements.
70   *
71   * @author Andrei Adamchik
72   */
73 public class UpdateTranslator extends QueryAssembler {
74
75     public String JavaDoc aliasForTable(DbEntity dbEnt) {
76         throw new RuntimeException JavaDoc("aliases not supported");
77     }
78
79     public void dbRelationshipAdded(DbRelationship dbRel) {
80         throw new RuntimeException JavaDoc("db relationships not supported");
81     }
82
83     /** Method that converts an update query into SQL string */
84     public String JavaDoc createSqlString() throws Exception JavaDoc {
85         StringBuffer JavaDoc queryBuf = new StringBuffer JavaDoc();
86         queryBuf.append("UPDATE ");
87
88         // 1. append table name
89 DbEntity dbEnt = getRootEntity().getDbEntity();
90         queryBuf.append(dbEnt.getFullyQualifiedName());
91
92         // 2. build "set ..." clause
93 buildSetClause(queryBuf, (UpdateQuery) query);
94
95         // 3. build qualifier
96 String JavaDoc qualifierStr =
97             adapter.getQualifierTranslator(this).doTranslation();
98         if (qualifierStr != null)
99             queryBuf.append(" WHERE ").append(qualifierStr);
100
101         return queryBuf.toString();
102     }
103
104     /** Translate updated values and relationships into
105      * "SET ATTR1 = Val1, ..." SQL statement.
106      */
107     private void buildSetClause(StringBuffer JavaDoc queryBuf, UpdateQuery query) {
108         Map JavaDoc updAttrs = query.getUpdAttributes();
109         // set of keys.. each key is supposed to be ObjAttribute
110 Iterator JavaDoc attrIt = updAttrs.keySet().iterator();
111
112         if (!attrIt.hasNext())
113             throw new CayenneRuntimeException("Nothing to update.");
114
115         DbEntity dbEnt = getRootEntity().getDbEntity();
116         queryBuf.append(" SET ");
117
118         // append updated attribute values
119 boolean appendedSomething = false;
120
121         // now process other attrs in the loop
122 while (attrIt.hasNext()) {
123             String JavaDoc nextKey = (String JavaDoc) attrIt.next();
124             Object JavaDoc attrVal = updAttrs.get(nextKey);
125
126             if (appendedSomething)
127                 queryBuf.append(", ");
128
129             queryBuf.append(nextKey).append(" = ?");
130             super.addToParamList(
131                 (DbAttribute) dbEnt.getAttribute(nextKey),
132                 attrVal);
133             appendedSomething = true;
134         }
135     }
136 }
137
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