genericexecutioncontext.java

derby database source code.good for you.

/*

   Derby - Class org.apache.derby.impl.sql.execute.GenericExecutionContext

   Copyright 1997, 2004 The Apache Software Foundation or its licensors, as applicable.

   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.apache.derby.impl.sql.execute;

import org.apache.derby.iapi.sql.execute.ExecutionContext;
import org.apache.derby.iapi.sql.execute.ExecutionFactory;
import org.apache.derby.iapi.sql.execute.ResultSetFactory;
import org.apache.derby.iapi.sql.execute.ResultSetStatisticsFactory;

import org.apache.derby.iapi.sql.ResultSet;

import org.apache.derby.iapi.services.sanity.SanityManager;

import org.apache.derby.iapi.services.context.ContextImpl;
import org.apache.derby.iapi.services.context.ContextManager;

import org.apache.derby.iapi.services.monitor.Monitor;

import org.apache.derby.iapi.error.StandardException;

import java.util.Properties;
import org.apache.derby.iapi.error.ExceptionSeverity;
/**
 * ExecutionContext stores the result set factory to be used by
 * the current connection, and manages execution-level connection
 * activities.
 * <p>
 * An execution context is expected to be on the stack for the
 * duration of the connection.
 *
 * @author ames
 */
public class GenericExecutionContext
	extends ContextImpl 
	implements ExecutionContext {

	private ResultSet sourceRS;

	//
	// class implementation
	//
	protected ResultSetFactory rsFactory;
	protected ResultSetStatisticsFactory rssFactory;
	protected ExecutionFactory execFactory;

	//
	// ExecutionContext interface
	//
	/**
	 * Get the ResultSetFactory from this ExecutionContext.
	 *
	 * @return	The result set factory associated with this
	 *		ExecutionContext
	 */
	public ResultSetFactory getResultSetFactory() 
	{
		/* null rsFactory may have been passed to
		 * constructor in order to speed up boot time.
		 */
		if (rsFactory == null)
		{
			rsFactory = execFactory.getResultSetFactory();
		}
		return rsFactory;
	}

	/**
	 * Get the ResultSetStatisticsFactory from this ExecutionContext.
	 *
	 * @return	The result set statistics factory associated with this
	 *		ExecutionContext
	 *
	 * @exception StandardException		Thrown on error
	 */
	public ResultSetStatisticsFactory getResultSetStatisticsFactory()
					throws StandardException {
		if (rssFactory == null) {
			rssFactory = (ResultSetStatisticsFactory)
				Monitor.bootServiceModule(
									false,
									execFactory,
									ResultSetStatisticsFactory.MODULE,
									(Properties) null);
		}

		return rssFactory;
	}

	public ExecutionFactory getExecutionFactory() {
		return execFactory;
	}

	/**
	 * @see ExecutionContext#beginStatement
	 * @exception StandardException Thrown on error
	 */
	public void beginStatement(ResultSet sourceRS) throws StandardException {
		this.sourceRS = sourceRS;
	}

	/**
	 * @see ExecutionContext#endStatement
	 * @exception StandardException Thrown on error
	 */
	public void endStatement() throws StandardException {
		sourceRS = null;
	}

	/**
	 * @see ExecutionContext#siftForeignKeys
	 * @exception StandardException Thrown on error
	 */
	public	Object[]	siftForeignKeys( Object[] fullList ) throws StandardException
	{
		// for the Core Language, this routine is a NOP. The interesting
		// cases occur during REFRESH and the initial boot of a Target
		// database. See RepExecutionContext for the interesting cases.

		return	fullList;
	}

	/**
	 * @see ExecutionContext#siftTriggers
	 * @exception StandardException Thrown on error
	 */
	public Object siftTriggers(Object triggerInfo) throws StandardException
	{
		// for the Core Language, this routine is a NOP. The interesting
		// cases occur during REFRESH and the initial boot of a Target
		// database. See RepExecutionContext for the interesting cases.
		return	triggerInfo;
	}

	//
	// Context interface
	//

	/**
	 * @exception StandardException Thrown on error
	 */
	public void cleanupOnError(Throwable error) throws StandardException {
		if (error instanceof StandardException) {

			StandardException se = (StandardException) error;
			if (se.getSeverity() > ExceptionSeverity.STATEMENT_SEVERITY)
				return;


			if (sourceRS != null)
			{
				sourceRS.close();
				sourceRS = null;
			}

			endStatement();
			return;
		}
	}

	//
	// class interface
	//
	public	GenericExecutionContext(
		    ResultSetFactory rsf,
			ContextManager cm,
			ExecutionFactory ef)
	{

		super(cm, ExecutionContext.CONTEXT_ID);
		rsFactory = rsf;
		execFactory = ef;
	}

}