com.akiban.sql.parser
Class UnaryOperatorNode

java.lang.Object
  com.akiban.sql.parser.QueryTreeNode
      com.akiban.sql.parser.ValueNode
          com.akiban.sql.parser.UnaryOperatorNode

All Implemented Interfaces:

Visitable

Direct Known Subclasses:

AggregateNode, ExtractOperatorNode, LengthOperatorNode, OctetLengthOperatorNode, SimpleStringOperatorNode, UnaryArithmeticOperatorNode, UnaryBitOperatorNode, UnaryComparisonOperatorNode, UnaryDateTimestampOperatorNode, UnaryLogicalOperatorNode, WindowFunctionNode, XMLUnaryOperatorNode

public class UnaryOperatorNode
extends ValueNode

A UnaryOperatorNode represents a built-in unary operator as defined by the ANSI/ISO SQL standard. This covers operators like +, -, NOT, and IS NULL. Java operators are not represented here: the JSQL language allows Java methods to be called from expressions, but not Java operators.

Field Summary

protected String	methodName
protected String	operator
protected String	receiverInterfaceType
protected String	resultInterfaceType

Fields inherited from class com.akiban.sql.parser.QueryTreeNode

AUTOINCREMENT_CREATE_MODIFY, AUTOINCREMENT_INC_INDEX, AUTOINCREMENT_IS_AUTOINCREMENT_INDEX, AUTOINCREMENT_START_INDEX

Constructor Summary

UnaryOperatorNode()

Method Summary

void	copyFrom(QueryTreeNode node) Fill this node with a deep copy of the given node.
String	getMethodName()
ValueNode	getOperand() Get the operand of this unary operator.
String	getOperator() Get the operator of this unary operator.
void	init(Object operand) Initializer for a UnaryOperatorNode
void	init(Object operand, Object operatorOrOpType, Object methodNameOrAddedArgs) Initializer for a UnaryOperatorNode.
protected boolean	isEquivalent(ValueNode o) Tests if this node is equivalent to the specified ValueNode.
void	printSubNodes(int depth) Prints the sub-nodes of this object.
void	setOperand(ValueNode operand)
String	toString() Convert this object to a String.

Methods inherited from class com.akiban.sql.parser.ValueNode

getColumnName, getSchemaName, getSourceResultColumn, getTableName, getType, getTypeId, init, isBinaryEqualsOperatorNode, isBooleanFalse, isBooleanTrue, isConstantExpression, isInListProbeNode, isParameterNode, isRelationalOperator, isSameNodeType, setNullability, setType

Methods inherited from class com.akiban.sql.parser.QueryTreeNode

accept, convertDefaultNode, debugFlush, debugPrint, formatNodeString, getBeginOffset, getDebugOutput, getEndOffset, getNodeFactory, getNodeType, getNullNode, getParserContext, getStatementType, getUserData, init, init, init, init, init, init, init, init, init, init, init, isInstanceOf, makeTableName, makeTableName, nodeHeader, printLabel, setBeginOffset, setDebugOutput, setEndOffset, setNodeType, setParserContext, setUserData, stackPrint, treePrint, treePrint, treePrint

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

operator

protected String operator

methodName

protected String methodName

resultInterfaceType

protected String resultInterfaceType

receiverInterfaceType

protected String receiverInterfaceType

Constructor Detail

UnaryOperatorNode

public UnaryOperatorNode()

Method Detail

init

public void init(Object operand,
                 Object operatorOrOpType,
                 Object methodNameOrAddedArgs)
          throws StandardException

Initializer for a UnaryOperatorNode.

Overrides:

init in class QueryTreeNode

Parameters:

operand - The operand of the node

operator - The name of the operator,

methodName - Name of the method

Throws:

StandardException - Thrown on error

init

public void init(Object operand)
          throws StandardException

Initializer for a UnaryOperatorNode

Overrides:

init in class QueryTreeNode

Parameters:

operand - The operand of the node

Throws:

StandardException - Thrown on error

copyFrom

public void copyFrom(QueryTreeNode node)
              throws StandardException

Fill this node with a deep copy of the given node.

Overrides:

copyFrom in class ValueNode

Throws:

StandardException

getOperator

public String getOperator()

Get the operator of this unary operator.

Returns:

The operator of this unary operator.

getMethodName

public String getMethodName()

toString

public String toString()

Convert this object to a String. See comments in QueryTreeNode.java for how this should be done for tree printing.

Overrides:

toString in class ValueNode

Returns:

This object as a String

printSubNodes

public void printSubNodes(int depth)

Prints the sub-nodes of this object. See QueryTreeNode.java for how tree printing is supposed to work.

Overrides:

printSubNodes in class QueryTreeNode

Parameters:

depth - The depth of this node in the tree

getOperand

public ValueNode getOperand()

Get the operand of this unary operator.

Returns:

The operand of this unary operator.

setOperand

public void setOperand(ValueNode operand)

isEquivalent

protected boolean isEquivalent(ValueNode o)
                        throws StandardException

Description copied from class: ValueNode

Tests if this node is equivalent to the specified ValueNode. Two ValueNodes are considered equivalent if they will evaluate to the same value during query execution.

This method provides basic expression matching facility for the derived class of ValueNode and it is used by the language layer to compare the node structural form of the two expressions for equivalence at bind phase.

Note that it is not comparing the actual row values at runtime to produce a result; hence, when comparing SQL NULLs, they are considered to be equivalent and not unknown.

One usage case of this method in this context is to compare the select column expression against the group by expression to check if they are equivalent. e.g.:

SELECT c1+c2 FROM t1 GROUP BY c1+c2

In general, node equivalence is determined by the derived class of ValueNode. But they generally abide to the rules below:

• The two ValueNodes must be of the same node type to be considered equivalent. e.g.: CastNode vs. CastNode - equivalent (if their args also match), ColumnReference vs CastNode - not equivalent.
• If node P contains other ValueNode(s) and so on, those node(s) must also be of the same node type to be considered equivalent.
• If node P takes a parameter list, then the number of arguments and its arguments for the two nodes must also match to be considered equivalent. e.g.: CAST(c1 as INTEGER) vs CAST(c1 as SMALLINT), they are not equivalent.
• When comparing SQL NULLs in this context, they are considered to be equivalent.
• If this does not apply or it is determined that the two nodes are not equivalent then the derived class of this method should return false; otherwise, return true.

Specified by:

isEquivalent in class ValueNode

Parameters:

o - the node to compare this ValueNode against.

Returns:

true if the two nodes are equivalent, false otherwise.

Throws:

StandardException