/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.openjpa.jdbc.meta.strats;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import org.apache.commons.lang.StringUtils;
import org.apache.openjpa.jdbc.kernel.JDBCFetchConfiguration;
import org.apache.openjpa.jdbc.kernel.JDBCStore;
import org.apache.openjpa.jdbc.meta.ClassMapping;
import org.apache.openjpa.jdbc.schema.Column;
import org.apache.openjpa.jdbc.sql.DBDictionary;
import org.apache.openjpa.jdbc.sql.SQLBuffer;
import org.apache.openjpa.lib.log.Log;
import org.apache.openjpa.lib.util.Localizer;
import org.apache.openjpa.meta.JavaTypes;
/**
* Stores the class name along with each database object record.
*
* @author Abe White
*/
public class ClassNameDiscriminatorStrategy
extends InValueDiscriminatorStrategy {
private static final Localizer _loc = Localizer.forPackage
(ClassNameDiscriminatorStrategy.class);
public static final String ALIAS = "class-name";
public String getAlias() {
return ALIAS;
}
protected int getJavaType() {
return JavaTypes.STRING;
}
protected Object getDiscriminatorValue(ClassMapping cls) {
return cls.getDescribedType().getName();
}
protected Class getClass(Object val, JDBCStore store)
throws ClassNotFoundException {
ClassLoader loader = getClassLoader(store);
return Class.forName((String) val, true, loader);
}
public void loadSubclasses(JDBCStore store)
throws SQLException, ClassNotFoundException {
if (isFinal) {
disc.setSubclassesLoaded(true);
return;
}
Column col = disc.getColumns()[0];
DBDictionary dict = store.getDBDictionary();
JDBCFetchConfiguration fetch = store.getFetchConfiguration();
SQLBuffer select = dict.toSelect(new SQLBuffer(dict).append(col),
fetch, new SQLBuffer(dict).append(col.getTable()), null, null,
null, null, true, false, 0, Long.MAX_VALUE);
Log log = disc.getMappingRepository().getLog();
if (log.isTraceEnabled())
log.trace(_loc.get("load-subs", col.getTable().getFullName()));
ClassLoader loader = getClassLoader(store);
Connection conn = store.getConnection();
PreparedStatement stmnt = null;
ResultSet rs = null;
try {
stmnt = select.prepareStatement(conn);
dict.setTimeouts(stmnt, fetch, false);
rs = stmnt.executeQuery();
String className;
while (rs.next()) {
className = dict.getString(rs, 1);
if (StringUtils.isEmpty(className))
throw new ClassNotFoundException(_loc.get("no-class-name",
disc.getClassMapping(), col).getMessage());
Class.forName(className, true, loader);
}
disc.setSubclassesLoaded(true);
} finally {
if (rs != null)
try {
rs.close();
} catch (SQLException se) {
}
if (stmnt != null)
try {
stmnt.close();
} catch (SQLException se) {
}
try {
conn.close();
} catch (SQLException se) {
}
}
}
/**
* Return the class loader to use for loading class names.
*/
private ClassLoader getClassLoader(JDBCStore store) {
return store.getConfiguration().getClassResolverInstance().
getClassLoader(disc.getClassMapping().getDescribedType(),
store.getContext().getClassLoader());
}
}