materializeresultsetnode.java

derby database source code.good for you.

/*

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

   Copyright 1998, 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.sql.compile.Optimizable;
import org.apache.derby.iapi.sql.compile.OptimizableList;
import org.apache.derby.iapi.sql.compile.OptimizablePredicate;
import org.apache.derby.iapi.sql.compile.OptimizablePredicateList;
import org.apache.derby.iapi.sql.compile.Optimizer;
import org.apache.derby.iapi.sql.compile.Visitable;
import org.apache.derby.iapi.sql.compile.Visitor;
import org.apache.derby.iapi.sql.compile.RequiredRowOrdering;

import org.apache.derby.iapi.sql.dictionary.DataDictionary;

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

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

import org.apache.derby.impl.sql.compile.ActivationClassBuilder;

import org.apache.derby.iapi.services.compiler.MethodBuilder;

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

import org.apache.derby.iapi.services.classfile.VMOpcode;

import java.util.Properties;

/**
 * A MaterializeResultSetNode represents a materialization result set for any 
 * child result set that needs one.
 *
 * @author Jerry Brenner
 */

public class MaterializeResultSetNode extends SingleChildResultSetNode
{
	/**
	 * Initializer for a MaterializeResultSetNode.
	 *
	 * @param childResult	The child ResultSetNode
	 * @param rcl			The RCL for the node
	 * @param tableProperties	Properties list associated with the table
	 */

	public void init(Object childResult,
								Object rcl,
								Object tableProperties)
	{
		super.init(childResult, tableProperties);
		resultColumns = (ResultColumnList) rcl;
	}

	/**
	 * Prints the sub-nodes of this object.  See QueryTreeNode.java for
	 * how tree printing is supposed to work.
	 *
	 * @param depth		The depth of this node in the tree
	 *
	 * @return	Nothing
	 */

	public void printSubNodes(int depth)
	{
		if (SanityManager.DEBUG)
		{
			super.printSubNodes(depth);
		}
	}

    /**
     *
	 *
	 * @exception StandardException		Thrown on error
     */
	public void generate(ActivationClassBuilder acb,
								MethodBuilder mb)
							throws StandardException
	{
		if (SanityManager.DEBUG)
        SanityManager.ASSERT(resultColumns != null, "Tree structure bad");

		/* Get the next ResultSet #, so that we can number this ResultSetNode, its
		 * ResultColumnList and ResultSet.
		 */
		assignResultSetNumber();

		// Get the cost estimate from the child if we don't have one yet
		costEstimate = childResult.getFinalCostEstimate();

		// build up the tree.

		// Generate the child ResultSet
		acb.pushGetResultSetFactoryExpression(mb);

		childResult.generate(acb, mb);
		acb.pushThisAsActivation(mb);
		mb.push(resultSetNumber);
		mb.push(costEstimate.rowCount());
		mb.push(costEstimate.getEstimatedCost());
		closeMethodArgument(acb, mb);

		mb.callMethod(VMOpcode.INVOKEINTERFACE, (String) null, "getMaterializedResultSet",
						ClassName.NoPutResultSet, 6);
	}
}