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

/*

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

   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 java.util.List;
import org.apache.derby.iapi.error.StandardException;
import org.apache.derby.iapi.reference.SQLState;
import org.apache.derby.iapi.services.context.ContextManager;
import org.apache.derby.shared.common.sanity.SanityManager;
import org.apache.derby.iapi.sql.compile.Visitor;
import org.apache.derby.iapi.types.DataTypeDescriptor;
import org.apache.derby.iapi.types.TypeId;
import org.apache.derby.iapi.util.JBitSet;

/**
 * A BinaryListOperatorNode represents a built-in "binary" operator with a single
 * operand on the left of the operator and a list of operands on the right.
 * This covers operators such as IN and BETWEEN.
 *
 */

public abstract class BinaryListOperatorNode extends ValueNode
{
	String	methodName;
	/* operator used for error messages */
	String	operator;

	ValueNode		leftOperand;
	ValueNodeList	rightOperandList;

    BinaryListOperatorNode(
            ValueNode leftOperand,
            ValueNodeList rightOperandList,
            String operator,
            String methodName,
            ContextManager cm) throws SecurityException {
        super(cm);
        this.leftOperand = leftOperand;
        this.rightOperandList = rightOperandList;
        this.operator = operator;
        this.methodName = methodName;
    }

	/**
	 * 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
	 */
    @Override
	public String toString()
	{
		if (SanityManager.DEBUG)
		{
			return "operator: " + operator + "\n" +
				   "methodName: " + methodName + "\n" +
				super.toString();
		}
		else
		{
			return "";
		}
	}

	/**
	 * 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
	 */
    @Override
    void printSubNodes(int depth)
	{
		if (SanityManager.DEBUG)
		{
			super.printSubNodes(depth);

			if (leftOperand != null)
			{
				printLabel(depth, "leftOperand: ");
				leftOperand.treePrint(depth + 1);
			}

			if (rightOperandList != null)
			{
				printLabel(depth, "rightOperandList: ");
				rightOperandList.treePrint(depth + 1);
			}
		}
	}

	/**
	 * Bind this expression.  This means binding the sub-expressions,
	 * as well as figuring out what the return type is for this expression.
	 *
	 * @param fromList		The FROM list for the query this
	 *				expression is in, for binding columns.
	 * @param subqueryList		The subquery list being built as we find SubqueryNodes
     * @param aggregates        The aggregate list being built as we find AggregateNodes
	 *
	 * @return	The new top of the expression tree.
	 *
	 * @exception StandardException		Thrown on error
	 */
    @Override
    ValueNode bindExpression(
        FromList fromList, SubqueryList subqueryList, List<AggregateNode> aggregates)
			throws StandardException
	{
        leftOperand = leftOperand.bindExpression(fromList, subqueryList, aggregates);
        rightOperandList.bindExpression(fromList, subqueryList, aggregates);

		/* Is there a ? parameter on the left? */
		if (leftOperand.requiresTypeFromContext())
		{
			/*
			** It's an error if both operands are all ? parameters.
			*/
			if (rightOperandList.containsAllParameterNodes())
			{
				throw StandardException.newException(SQLState.LANG_BINARY_OPERANDS_BOTH_PARMS, 
																	operator);
			}

			/* Set the left operand to the type of right parameter. */
			leftOperand.setType(rightOperandList.getTypeServices());
		}

		/* Is there a ? parameter on the right? */
		if (rightOperandList.containsParameterNode())
		{
			/* Set the right operand to the type of the left parameter. */
			rightOperandList.setParameterDescriptor(leftOperand.getTypeServices());
		}

		/* If the left operand is not a built-in type, then generate a conversion
		 * tree to a built-in type.
		 */
		if (leftOperand.getTypeId().userType())
		{
			leftOperand = leftOperand.genSQLJavaSQLTree();
		}

		/* Generate bound conversion trees for those elements in the rightOperandList
		 * that are not built-in types.
		 */
		rightOperandList.genSQLJavaSQLTrees();

		/* Test type compatability and set type info for this node */
		bindComparisonOperator();

		return this;
	}

	/**
	 * Test the type compatability of the operands and set the type info
	 * for this node.  This method is useful both during binding and
	 * when we generate nodes within the language module outside of the parser.
	 *
	 * @exception StandardException		Thrown on error
	 */
    void bindComparisonOperator()
			throws StandardException
	{
		boolean				nullableResult;

		/* Can the types be compared to each other? */
		rightOperandList.comparable(leftOperand);

		/*
		** Set the result type of this comparison operator based on the
		** operands.  The result type is always SQLBoolean - the only question
		** is whether it is nullable or not.  If either the leftOperand or
		** any of the elements in the rightOperandList is
		** nullable, the result of the comparison must be nullable, too, so
		** we can represent the unknown truth value.
		*/
		nullableResult = leftOperand.getTypeServices().isNullable() ||
							rightOperandList.isNullable();
		setType(new DataTypeDescriptor(TypeId.BOOLEAN_ID, nullableResult));
	}

	/**
	 * Preprocess an expression tree.  We do a number of transformations
	 * here (including subqueries, IN lists, LIKE and BETWEEN) plus
	 * subquery flattening.
	 * NOTE: This is done before the outer ResultSetNode is preprocessed.
	 *
	 * @param	numTables			Number of tables in the DML Statement
	 * @param	outerFromList		FromList from outer query block
	 * @param	outerSubqueryList	SubqueryList from outer query block
	 * @param	outerPredicateList	PredicateList from outer query block
	 *
	 * @return		The modified expression
	 *
	 * @exception StandardException		Thrown on error
	 */
    @Override
    ValueNode preprocess(int numTables,
								FromList outerFromList,
								SubqueryList outerSubqueryList,
								PredicateList outerPredicateList) 
					throws StandardException
	{
		leftOperand = leftOperand.preprocess(numTables,
											 outerFromList, outerSubqueryList,
											 outerPredicateList);
 		rightOperandList.preprocess(numTables,
									outerFromList, outerSubqueryList,
									outerPredicateList);
		return this;
	}

	/**
	 * Set the leftOperand to the specified ValueNode
	 *
	 * @param newLeftOperand	The new leftOperand
	 */
    void setLeftOperand(ValueNode newLeftOperand)
	{
		leftOperand = newLeftOperand;
	}

	/**
	 * Get the leftOperand
	 *
	 * @return The current leftOperand.
	 */
    ValueNode getLeftOperand()
	{
		return leftOperand;
	}

	/**
	 * Set the rightOperandList to the specified ValueNodeList
	 *
	 * @param newRightOperandList	The new rightOperandList
	 *
	 */
    void setRightOperandList(ValueNodeList newRightOperandList)
	{
		rightOperandList = newRightOperandList;
	}

	/**
	 * Get the rightOperandList
	 *
	 * @return The current rightOperandList.
	 */
    ValueNodeList getRightOperandList()
	{
		return rightOperandList;
	}

	/**
	 * Categorize this predicate.  Initially, this means
	 * building a bit map of the referenced tables for each predicate.
	 * If the source of this ColumnReference (at the next underlying level) 
	 * is not a ColumnReference or a VirtualColumnNode then this predicate
	 * will not be pushed down.
	 *
	 * For example, in:
	 *		select * from (select 1 from s) a (x) where x = 1
	 * we will not push down x = 1.
	 * NOTE: It would be easy to handle the case of a constant, but if the
	 * inner SELECT returns an arbitrary expression, then we would have to copy
	 * that tree into the pushed predicate, and that tree could contain
	 * subqueries and method calls.
	 * RESOLVE - revisit this issue once we have views.
	 *
	 * @param referencedTabs	JBitSet with bit map of referenced FromTables
	 * @param simplePredsOnly	Whether or not to consider method
	 *							calls, field references and conditional nodes
	 *							when building bit map
	 *
	 * @return boolean		Whether or not source.expression is a ColumnReference
	 *						or a VirtualColumnNode.
	 * @exception StandardException			Thrown on error
	 */
    @Override
    boolean categorize(JBitSet referencedTabs, boolean simplePredsOnly)
		throws StandardException
	{
		boolean pushable;
		pushable = leftOperand.categorize(referencedTabs, simplePredsOnly);
		pushable = (rightOperandList.categorize(referencedTabs, simplePredsOnly) && pushable);
		return pushable;
	}

	/**
	 * Remap all ColumnReferences in this tree to be clones of the
	 * underlying expression.
	 *
	 * @return ValueNode			The remapped expression tree.
	 *
	 * @exception StandardException			Thrown on error
	 */
    @Override
    ValueNode remapColumnReferencesToExpressions()
		throws StandardException
	{
		// we need to assign back because a new object may be returned, beetle 4983
		leftOperand = leftOperand.remapColumnReferencesToExpressions();
		rightOperandList.remapColumnReferencesToExpressions();
		return this;
	}

	/**
	 * Return whether or not this expression tree represents a constant expression.
	 *
	 * @return	Whether or not this expression tree represents a constant expression.
	 */
    @Override
    boolean isConstantExpression()
	{
		return (leftOperand.isConstantExpression() &&
				rightOperandList.isConstantExpression());
	}

	/** @see ValueNode#constantExpression */
    @Override
    boolean constantExpression(PredicateList whereClause)
	{
		return (leftOperand.constantExpression(whereClause) &&
				rightOperandList.constantExpression(whereClause));
	}

	/**
	 * Return the variant type for the underlying expression.
	 * The variant type can be:
	 *		VARIANT				- variant within a scan
	 *							  (method calls and non-static field access)
	 *		SCAN_INVARIANT		- invariant within a scan
	 *							  (column references from outer tables)
	 *		QUERY_INVARIANT		- invariant within the life of a query
	 *		CONSTANT			- immutable
	 *
	 * @return	The variant type for the underlying expression.
	 * @exception StandardException	thrown on error
	 */
    @Override
	protected int getOrderableVariantType() throws StandardException
	{
		int leftType = leftOperand.getOrderableVariantType();
		int rightType = rightOperandList.getOrderableVariantType();

		return Math.min(leftType, rightType);
	}

	/**
	 * Accept the visitor for all visitable children of this node.
	 * 
	 * @param v the visitor
	 *
	 * @exception StandardException on error
	 */
    @Override
	void acceptChildren(Visitor v)
		throws StandardException
	{
		super.acceptChildren(v);

		if (leftOperand != null)
		{
			leftOperand = (ValueNode)leftOperand.accept(v);
		}
			
		if (rightOperandList != null)
		{
			rightOperandList = (ValueNodeList)rightOperandList.accept(v);
		}
	}
        
        /**
         * @inheritDoc
         */
    boolean isEquivalent(ValueNode o) throws StandardException
	{
        if (! isSameNodeKind(o)) {
			return false;
		}

		BinaryListOperatorNode other = (BinaryListOperatorNode)o;
		if (!operator.equals(other.operator)
				|| !leftOperand.isEquivalent(other.getLeftOperand())) 
		{
			return false;
		}

        if (!rightOperandList.isEquivalent(other.rightOperandList))
        {
            return false;
        }

		return true;
	}
}