scrollinsensitiveresultsetnode.java

derby database source code.good for you.

/*

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

   Copyright 1999, 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.CostEstimate;
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.reference.ClassName;

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

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

import java.util.Properties;

/**
 * A ScrollInsensitiveResultSetNode represents the insensitive scrolling cursor
 * functionality for any 
 * child result set that needs one.
 *
 * @author Jerry Brenner
 */

public class ScrollInsensitiveResultSetNode  extends SingleChildResultSetNode
{
	/**
	 * Initializer for a ScrollInsensitiveResultSetNode.
	 *
	 * @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)
	{
		init(childResult, tableProperties);
		resultColumns = (ResultColumnList) rcl;
	}

    /**
     *
	 *
	 * @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();

		// build up the tree.

		// Generate the child ResultSet

		// Get the cost estimate for the child
		costEstimate = childResult.getFinalCostEstimate();

		int erdNumber = acb.addItem(makeResultDescription());

		acb.pushGetResultSetFactoryExpression(mb);

		childResult.generate(acb, mb);
		acb.pushThisAsActivation(mb);
		mb.push(resultSetNumber);
		mb.push(resultColumns.size());

		mb.pushThis();
		mb.callMethod(VMOpcode.INVOKEVIRTUAL, ClassName.BaseActivation, "getScrollable",
						"boolean", 0);

		mb.push(costEstimate.rowCount());
		mb.push(costEstimate.getEstimatedCost());
		closeMethodArgument(acb, mb);

		mb.callMethod(VMOpcode.INVOKEINTERFACE, (String) null, "getScrollInsensitiveResultSet",
						ClassName.NoPutResultSet, 8);
	}
}