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1
22 package org.jboss.ejb.plugins.cmp.jdbc;
23
24 import java.sql.Connection  ;
25 import java.sql.PreparedStatement ;
26 import java.util.Iterator ;
27 import javax.ejb.EJBException ;
28 import javax.sql.DataSource ;
29 import org.jboss.ejb.plugins.cmp.jdbc.bridge.JDBCCMPFieldBridge;
30 import org.jboss.ejb.plugins.cmp.jdbc.bridge.JDBCCMRFieldBridge;
31 import org.jboss.logging.Logger;
32
33
40 public final class JDBCDeleteRelationsCommand
41 {
42 private final Logger log;
43 private int maxKeysInDelete;
44 private String maxKeysStatement;
45
46 public JDBCDeleteRelationsCommand(JDBCStoreManager manager)
47 {
48 log = Logger.getLogger(this.getClass().getName() +
50 "." +
51 manager.getMetaData().getName()
52 );
53
54 maxKeysInDelete = manager.getJDBCTypeFactory().getTypeMapping().getMaxKeysInDelete();
55 }
56
57 public void execute(RelationData relationData)
62 {
63 if(relationData.removedRelations.size() == 0)
64 {
65 return;
66 }
67
68 Iterator pairs = relationData.removedRelations.iterator();
69 int i = 0;
70 while(i < relationData.removedRelations.size())
71 {
72 String sql = getSQL(relationData, relationData.removedRelations.size() - i);
73
74 Connection con = null;
75 PreparedStatement ps = null;
76 JDBCCMRFieldBridge cmrField = relationData.getLeftCMRField();
77 try
78 {
79 if(log.isDebugEnabled())
81 {
82 log.debug("Executing SQL: " + sql);
83 }
84
85 DataSource dataSource = cmrField.getDataSource();
87 con = dataSource.getConnection();
88 ps = con.prepareStatement(sql);
89
90 setParameters(ps, relationData, pairs);
92
93 int rowsAffected = ps.executeUpdate();
95 if(log.isDebugEnabled())
96 {
97 log.debug("Rows affected = " + rowsAffected);
98 }
99
100 i += (maxKeysInDelete > 0 ? maxKeysInDelete : relationData.removedRelations.size());
101 }
102 catch(Exception e)
103 {
104 throw new EJBException ("Could not delete relations from " +
105 cmrField.getQualifiedTableName(), e
106 );
107 }
108 finally
109 {
110 JDBCUtil.safeClose(ps);
111 JDBCUtil.safeClose(con);
112 }
113 }
114 }
115
116 private String getSQL(RelationData relationData, int keys)
117 {
118 if(maxKeysInDelete > 0 && keys >= maxKeysInDelete)
119 {
120 if(maxKeysStatement == null)
121 {
122 maxKeysStatement = createSQL(relationData, maxKeysInDelete);
123 }
124 return maxKeysStatement;
125 }
126 return createSQL(relationData, keys);
127 }
128
129 private static String createSQL(RelationData relationData, int keysInDelete)
130 {
131 JDBCCMRFieldBridge left = relationData.getLeftCMRField();
132 JDBCCMRFieldBridge right = relationData.getRightCMRField();
133
134 StringBuffer sql = new StringBuffer (300);
135 sql.append(SQLUtil.DELETE_FROM)
136 .append(left.getQualifiedTableName())
137 .append(SQLUtil.WHERE);
138
139 StringBuffer whereClause = new StringBuffer (20);
140 whereClause.append('(');
141 SQLUtil.getWhereClause(left.getTableKeyFields(), whereClause)
143 .append(SQLUtil.AND);
144 SQLUtil.getWhereClause(right.getTableKeyFields(), whereClause)
146 .append(')');
147 String whereClauseStr = whereClause.toString();
148 sql.append(whereClauseStr);
149 for(int i = 1; i < keysInDelete; ++i)
150 {
151 sql.append(SQLUtil.OR).append(whereClauseStr);
152 }
153
154 return sql.toString();
155 }
156
157 private void setParameters(PreparedStatement ps, RelationData relationData, Iterator pairs)
158 throws Exception
159 {
160 int index = 1;
161 JDBCCMPFieldBridge[] leftFields = (JDBCCMPFieldBridge[])relationData.getLeftCMRField().getTableKeyFields();
162 JDBCCMPFieldBridge[] rightFields = (JDBCCMPFieldBridge[])relationData.getRightCMRField().getTableKeyFields();
163 int keyIndex = 0;
164 while(pairs.hasNext())
165 {
166 RelationPair pair = (RelationPair)pairs.next();
167
168 Object leftId = pair.getLeftId();
170 for(int i = 0; i < leftFields.length; ++i)
171 {
172 index = leftFields[i].setPrimaryKeyParameters(ps, index, leftId);
173 }
174
175 Object rightId = pair.getRightId();
177 for(int i = 0; i < rightFields.length; ++i)
178 {
179 index = rightFields[i].setPrimaryKeyParameters(ps, index, rightId);
180 }
181
182 if(maxKeysInDelete > 0)
183 {
184 ++keyIndex;
185 if(keyIndex == maxKeysInDelete)
186 {
187 break;
188 }
189 }
190 }
191 }
192 }
193 |
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