java/engine/org/apache/derby/impl/sql/compile/HasCorrelatedCRsVisitor.java

/*

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

   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.derby.impl.sql.compile;

import org.apache.derby.iapi.sql.compile.Visitable; 
import org.apache.derby.iapi.sql.compile.Visitor;

/**
 * Find out if we have an correlated column reference
 * anywhere below us.  Stop traversal as soon as we find one.
 *
 */
class HasCorrelatedCRsVisitor implements Visitor
{
	private boolean hasCorrelatedCRs;

	/**
	 * Construct a visitor
	 */
    HasCorrelatedCRsVisitor()
	{
	}



	////////////////////////////////////////////////
	//
	// VISITOR INTERFACE
	//
	////////////////////////////////////////////////

	/**
	 * If we have found the target node, we are done.
	 *
	 * @param node 	the node to process
	 *
	 * @return me
	 */
	public Visitable visit(Visitable node)
	{
		if (node instanceof ColumnReference)
		{
			if (((ColumnReference)node).getCorrelated())
			{
				hasCorrelatedCRs = true;
			}
		}
		else if (node instanceof VirtualColumnNode)
		{
			if (((VirtualColumnNode)node).getCorrelated())
			{
				hasCorrelatedCRs = true;
			}
		}
		else if (node instanceof MethodCallNode)
		{
			/* trigger action references are correlated
			 */
			if (((MethodCallNode)node).getMethodName().equals("getTriggerExecutionContext") ||
				((MethodCallNode)node).getMethodName().equals("TriggerOldTransitionRows") ||
				((MethodCallNode)node).getMethodName().equals("TriggerNewTransitionRows")
			   )
			{
				hasCorrelatedCRs = true;
			}
		}
		return node;
	}

	/**
	 * Stop traversal if we found the target node
	 *
	 * @return true/false
	 */
	public boolean stopTraversal()
	{
		return hasCorrelatedCRs;
	}

	public boolean skipChildren(Visitable v)
	{
		return false;
	}

	public boolean visitChildrenFirst(Visitable v)
	{
		return false;
	}

	////////////////////////////////////////////////
	//
	// CLASS INTERFACE
	//
	////////////////////////////////////////////////
	/**
	 * Indicate whether we found the node in
	 * question
	 *
	 * @return true/false
	 */
    boolean hasCorrelatedCRs()
	{
		return hasCorrelatedCRs;
	}

	/**
	 * Shortcut to set if hasCorrelatedCRs
	 *
	 *	@param	value	true/false
	 */
    void setHasCorrelatedCRs(boolean value)
	{
		hasCorrelatedCRs = value;
	}
}