/*
* Copyright 2009 Ahmad Hassan, Ralf Joachim
*
* Licensed 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.castor.cpa.persistence.sql.keygen;
import java.sql.Connection;
import java.sql.SQLException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.castor.core.util.Messages;
import org.castor.cpa.persistence.sql.engine.CastorConnection;
import org.castor.cpa.persistence.sql.engine.CastorStatement;
import org.castor.cpa.persistence.sql.engine.SQLStatementInsertCheck;
import org.castor.cpa.persistence.sql.query.Insert;
import org.castor.cpa.persistence.sql.query.expression.Column;
import org.castor.cpa.persistence.sql.query.expression.Parameter;
import org.castor.persist.ProposedEntity;
import org.exolab.castor.jdo.Database;
import org.exolab.castor.jdo.PersistenceException;
import org.exolab.castor.jdo.engine.SQLColumnInfo;
import org.exolab.castor.jdo.engine.SQLEngine;
import org.exolab.castor.jdo.engine.SQLFieldInfo;
import org.exolab.castor.jdo.engine.nature.ClassDescriptorJDONature;
import org.exolab.castor.mapping.ClassDescriptor;
import org.exolab.castor.persist.spi.Identity;
import org.exolab.castor.persist.spi.PersistenceFactory;
/**
* Abstract Class that implements the KeyGenerator Interface for BEFORE_INSERT style. The key
* generator is used for producing identities for objects before they are created in the
* database.
*
* @author <a href="mailto:ahmad DOT hassan AT gmail DOT com">Ahmad Hassan</a>
* @author <a href="mailto:ralf DOT joachim AT syscon DOT eu">Ralf Joachim</a>
* @version $Revision$ $Date: 2009-07-13 17:22:43 (Tue, 28 Jul 2009) $
*/
public abstract class AbstractBeforeKeyGenerator extends AbstractKeyGenerator {
//-----------------------------------------------------------------------------------
/** The <a href="http://jakarta.apache.org/commons/logging/">Jakarta
* Commons Logging</a> instance used for all logging. */
private static final Log LOG = LogFactory.getLog(AbstractBeforeKeyGenerator.class);
/** Persistence factory for the database engine the entity is persisted in.
* Used to format the SQL statement. */
private PersistenceFactory _factory;
/** SQL engine for all persistence operations at entities of the type this
* class is responsible for. Holds all required information of the entity type. */
private SQLEngine _engine;
/** Represents the engine type obtained from clas descriptor. */
private String _engineType = null;
/** Name of the Table extracted from Class descriptor. */
private String _mapTo;
/** Variable to store built insert class hierarchy. */
private Insert _insert;
//-----------------------------------------------------------------------------------
/**
* Constructor.
*
* @param factory Persistence factory for the database engine the entity is persisted in.
* Used to format the SQL statement
*/
public AbstractBeforeKeyGenerator(final PersistenceFactory factory) {
_factory = factory;
}
//-----------------------------------------------------------------------------------
/**
* {@inheritDoc}
*/
public KeyGenerator buildStatement(final SQLEngine engine) {
_engine = engine;
ClassDescriptor clsDesc = _engine.getDescriptor();
_engineType = clsDesc.getJavaClass().getName();
_mapTo = new ClassDescriptorJDONature(clsDesc).getTableName();
_insert = new Insert(_mapTo);
SQLColumnInfo[] ids = _engine.getColumnInfoForIdentities();
for (int i = 0; i < ids.length; i++) {
String name = ids[i].getName();
_insert.addAssignment(new Column(name), new Parameter(name));
}
SQLFieldInfo[] fields = _engine.getInfo();
for (int i = 0; i < fields.length; ++i) {
if (fields[i].isStore()) {
SQLColumnInfo[] columns = fields[i].getColumnInfo();
for (int j = 0; j < columns.length; j++) {
String name = columns[j].getName();
_insert.addAssignment(new Column(name), new Parameter(name));
}
}
}
return this;
}
/**
* {@inheritDoc}
*/
public Object executeStatement(final Database database, final CastorConnection conn,
final Identity identity, final ProposedEntity entity) throws PersistenceException {
SQLStatementInsertCheck lookupStatement =
new SQLStatementInsertCheck(_engine, _factory);
Identity internalIdentity = identity;
SQLEngine extended = _engine.getExtends();
CastorStatement stmt = conn.createStatement();
try {
// must create record in the parent table first. all other dependents
// are created afterwards. quick and very dirty hack to try to make
// multiple class on the same table work.
if (extended != null) {
ClassDescriptor extDesc = extended.getDescriptor();
if (!new ClassDescriptorJDONature(extDesc).getTableName().equals(_mapTo)) {
internalIdentity = extended.create(database, conn.getConnection(),
entity, internalIdentity);
}
}
// generate key before INSERT.
internalIdentity = generateKey(database, conn);
// we only need to care on JDBC 3.0 at after INSERT.
stmt.prepareStatement(_insert);
//bind Identities
bindIdentity(internalIdentity, stmt);
//bind Fields
bindFields(entity, stmt);
if (LOG.isDebugEnabled()) {
LOG.debug(Messages.format("jdo.creating", _engineType, stmt.toString()));
}
stmt.executeUpdate();
stmt.close();
return internalIdentity;
} catch (SQLException except) {
LOG.fatal(Messages.format("jdo.storeFatal", _engineType, stmt.toString()), except);
// check for duplicate key the old fashioned way, after the INSERT
// failed to prevent race conditions and optimize INSERT times.
lookupStatement.insertDuplicateKeyCheck(conn, internalIdentity);
try {
if (stmt != null) { stmt.close(); }
} catch (SQLException except2) {
LOG.warn("Problem closing JDBC statement", except2);
}
throw new PersistenceException(Messages.format("persist.nested", except), except);
}
}
/**
* Binds the identity values.
*
* @param internalIdentity Identity values.
* @param stmt CastorStatement containing Connection and PersistenceFactory.
* @throws SQLException If a database access error occurs.
* @throws PersistenceException If identity size mismatches.
*/
public void bindIdentity(final Identity internalIdentity, final CastorStatement stmt)
throws SQLException, PersistenceException {
SQLColumnInfo[] ids = _engine.getColumnInfoForIdentities();
if (internalIdentity.size() != ids.length) {
throw new PersistenceException("Size of identity field mismatched!");
}
for (int i = 0; i < ids.length; i++) {
stmt.bindParameter(ids[i].getName(), ids[i].toSQL(internalIdentity.get(i)),
ids[i].getSqlType());
}
}
/**
* Binds parameters values to the PreparedStatement.
*
* @param entity Entity instance from which field values to be fetached to
* bind with sql insert statement.
* @param stmt CastorStatement containing Connection and PersistenceFactory.
* @throws SQLException If a database access error occurs.
* @throws PersistenceException If identity size mismatches.
*/
private void bindFields(final ProposedEntity entity, final CastorStatement stmt
) throws SQLException, PersistenceException {
SQLFieldInfo[] fields = _engine.getInfo();
for (int i = 0; i < fields.length; ++i) {
SQLColumnInfo[] columns = fields[i].getColumnInfo();
if (fields[i].isStore()) {
Object value = entity.getField(i);
if (value == null) {
for (int j = 0; j < columns.length; j++) {
stmt.bindParameter(columns[j].getName(), null, columns[j].getSqlType());
}
} else if (value instanceof Identity) {
Identity identity = (Identity) value;
if (identity.size() != columns.length) {
throw new PersistenceException("Size of identity field mismatch!");
}
for (int j = 0; j < columns.length; j++) {
stmt.bindParameter(columns[j].getName(), columns[j].toSQL(identity.get(j)),
columns[j].getSqlType());
}
} else {
if (columns.length != 1) {
throw new PersistenceException("Complex field expected!");
}
stmt.bindParameter(columns[0].getName(), columns[0].toSQL(value),
columns[0].getSqlType());
}
}
}
}
/**
* Generates the key.
*
* @param database Particular Database instance.
* @param conn CastorConnection holding connection and PersistenceFactory to be used to create
* statement.
* @return Identity that is generated.
* @throws PersistenceException If fails to Generate key.
*/
private Identity generateKey(final Database database, final CastorConnection conn)
throws PersistenceException {
SQLColumnInfo id = _engine.getColumnInfoForIdentities()[0];
// TODO [SMH]: Change KeyGenerator.isInSameConnection to KeyGenerator.useSeparateConnection?
// TODO [SMH]: Move "if (_keyGen.isInSameConnection() == false)"
// out of SQLEngine and into key-generator?
Connection connection = conn.getConnection();
if (!this.isInSameConnection()) {
connection = getSeparateConnection(database);
}
try {
Object identity;
synchronized (connection) {
identity = this.generateKey(connection, _mapTo, id.getName());
}
// TODO [SMH]: Move "if (identity == null)" into keygenerator.
if (identity == null) {
throw new PersistenceException(Messages.format("persist.noIdentity", _engineType));
}
return new Identity(id.toJava(identity));
} finally {
if (!this.isInSameConnection()) {
closeSeparateConnection(connection);
}
}
}
//-----------------------------------------------------------------------------------
}