nopstatementnode.java

derby database source code.good for you.

/*

   Derby - Class org.apache.derby.impl.sql.compile.NOPStatementNode

   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.compile;

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

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

/**
 * A NOPStatement node is for statements that don't do anything.  At the
 * time of this writing, the only statements that use it are
 * SET DB2J_DEBUG ON and SET DB2J_DEBUG OFF.  Both of these are
 * executed in the parser, so the statements don't do anything at execution
 */

public class NOPStatementNode extends StatementNode
{
	public String statementToString()
	{
		return "NO-OP";
	}

	/**
	 * Bind this NOP statement.  This throws an exception, because NOP
	 * statements by definition stop after parsing.
	 *
	 * @return	The bound query tree
	 *
	 * @exception StandardException		Always thrown to stop after parsing
	 */
	public QueryTreeNode bind() throws StandardException
	{
		/*
		** Prevent this statement from getting to execution by throwing
		** an exception during the bind phase.  This way, we don't
		** have to generate a class.
		*/

		throw StandardException.newException(SQLState.LANG_PARSE_ONLY);
	}

	int activationKind()
	{
		   return StatementNode.NEED_NOTHING_ACTIVATION;
	}
}