savepointnode.java

derby database source code.good for you.

/*

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

   Copyright 2003, 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.sanity.SanityManager;

import org.apache.derby.iapi.sql.execute.ConstantAction;

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

/**
 * A SavepointNode is the root of a QueryTree that represents a Savepoint (ROLLBACK savepoint, RELASE savepoint and SAVEPOINT)
 * statement.
 */

public class SavepointNode extends DDLStatementNode
{
	private String	savepointName; //name of the savepoint
	private int	savepointStatementType; //Type of savepoint statement ie rollback, release or set savepoint

	/**
	 * Initializer for a SavepointNode
	 *
	 * @param objectName		The name of the savepoint
	 * @param savepointStatementType		Type of savepoint statement ie rollback, release or set savepoint
	 *
	 * @exception StandardException		Thrown on error
	 */

	public void init(
			Object objectName,
			Object savepointStatementType)
		throws StandardException
	{
		initAndCheck(null);	
		this.savepointName = (String) objectName;
		this.savepointStatementType = ((Integer) savepointStatementType).intValue();

		if (SanityManager.DEBUG)
		{
			if (this.savepointStatementType > 3 || this.savepointStatementType < 1)
			{
				SanityManager.THROWASSERT(
				"Unexpected value for savepointStatementType = " + this.savepointStatementType + ". Expected value between 1-3");
			}
		}
	}

	/**
	 * Convert this object to a String.  See comments in QueryTreeNode.java
	 * for how this should be done for tree printing.
	 *
	 * @return	This object as a String
	 */

	public String toString()
	{
		if (SanityManager.DEBUG)
		{
			String tempString = "savepointName: " + "\n" + savepointName + "\n";
			tempString = tempString + "savepointStatementType: " + "\n" + savepointStatementType + "\n";
			return super.toString() +  tempString;
		}
		else
		{
			return "";
		}
	}

	public String statementToString()
	{
		if (savepointStatementType == 1)
			return "SAVEPOINT";
		else if (savepointStatementType == 2)
			return "ROLLBACK WORK TO SAVEPOINT";
		else
			return "RELEASE TO SAVEPOINT";
	}

	/**
	 * Returns whether or not this Statement requires a set/clear savepoint
	 * around its execution.  The following statement "types" do not require them:
	 *		Cursor	- unnecessary and won't work in a read only environment
	 *		Xact	- savepoint will get blown away underneath us during commit/rollback
	 *
	 * @return boolean	Whether or not this Statement requires a set/clear savepoint
	 */
	public boolean needsSavepoint()
	{
		return false;
	}

	// We inherit the generate() method from DDLStatementNode.

	/**
	 * Create the Constant information that will drive the guts of Execution.
	 *
	 * @exception StandardException		Thrown on failure
	 */
	public ConstantAction	makeConstantAction() throws StandardException
	{
		return(
            getGenericConstantActionFactory().getSavepointConstantAction(
                savepointName,
                savepointStatementType));
	}
}