org.apache.derby.impl.sql.compile
Class BooleanConstantNode

java.lang.Object
  org.apache.derby.impl.sql.compile.QueryTreeNode
      org.apache.derby.impl.sql.compile.ValueNode
          org.apache.derby.impl.sql.compile.ConstantNode
              org.apache.derby.impl.sql.compile.BooleanConstantNode

All Implemented Interfaces:

Visitable

public final class BooleanConstantNode

extends ConstantNode

Field Summary

(package private) boolean	booleanValue
(package private) boolean	unknownValue
protected DataValueDescriptor	value

Fields inherited from class org.apache.derby.impl.sql.compile.ValueNode

clause, dataTypeServices, IN_HAVING_CLAUSE, IN_SELECT_LIST, IN_UNKNOWN_CLAUSE, IN_WHERE_CLAUSE, transformed

Fields inherited from class org.apache.derby.impl.sql.compile.QueryTreeNode

AUTOINCREMENT_INC_INDEX, AUTOINCREMENT_IS_AUTOINCREMENT_INDEX, AUTOINCREMENT_START_INDEX, beginOffset, endOffset

Constructor Summary

BooleanConstantNode()

Method Summary

ValueNode	bindExpression(FromList fromList, SubqueryList subqueryList, java.util.Vector aggregateVector) Bind this expression.
boolean	constantExpression(PredicateList whereClause) Return whether or not this expression tree represents a constant value.
(package private) ValueNode	eliminateNots(boolean underNotNode) Eliminate NotNodes in the current query block.
(package private) void	generateConstant(ExpressionClassBuilder acb, MethodBuilder mb) This generates the proper constant.
void	generateExpression(ExpressionClassBuilder acb, MethodBuilder mb) For a ConstantNode, we generate the equivalent literal value.
ValueNode	getClone() Return a clone of this node.
(package private) java.lang.Object	getConstantValueAsObject() Return an Object representing the bind time value of this expression tree.
protected int	getOrderableVariantType() Return the variant type for the underlying expression.
DataValueDescriptor	getValue() Get the value in this ConstantNode
(package private) java.lang.String	getValueAsString() Return the value as a string.
void	init(java.lang.Object arg1) Initializer for a BooleanConstantNode.
void	init(java.lang.Object typeId, java.lang.Object nullable, java.lang.Object maximumWidth) Initializer for non-numeric types
(package private) boolean	isBooleanFalse() Does this represent a false constant.
(package private) boolean	isBooleanTrue() Does this represent a true constant.
boolean	isCloneable() Return whether or not this expression tree is cloneable.
boolean	isConstantExpression() Return whether or not this expression tree represents a constant expression.
boolean	isNull() Return whether or not this node represents a typed null constant.
double	selectivity(Optimizable optTable) The default selectivity for value nodes is 50%.
void	setValue(DataValueDescriptor value) Set the value in this ConstantNode.
java.lang.String	toString() Convert this object to a String.

Methods inherited from class org.apache.derby.impl.sql.compile.ValueNode

bindExpression, categorize, changeToCNF, checkIsBoolean, checkReliability, checkReliability, checkTopPredicatesForEqualsConditions, copyFields, genEqualsFalseTree, generate, generateFilter, genIsNullTree, genSQLJavaSQLTree, getClause, getColumnName, getDataValueFactory, getSchemaName, getSourceResultColumn, getTableName, getTablesReferenced, getTransformed, getTypeCompiler, getTypeId, getTypeServices, init, isBinaryEqualsOperatorNode, isParameterNode, isRelationalOperator, optimizableEqualityNode, preprocess, putAndsOnTop, remapColumnReferencesToExpressions, setClause, setDescriptor, setTransformed, setType, updatableByCursor, verifyChangeToCNF, verifyEliminateNots, verifyPutAndsOnTop

Methods inherited from class org.apache.derby.impl.sql.compile.QueryTreeNode

accept, bind, convertDefaultNode, debugFlush, debugPrint, executeSchemaName, executeStatementName, formatNodeString, foundString, generate, generateAuthorizeCheck, getBeginOffset, getClassFactory, getCompilerContext, getContextManager, getCursorInfo, getDataDictionary, getDependencyManager, getEndOffset, getExecutionFactory, getGenericConstantActionFactory, getIntProperty, getLanguageConnectionContext, getNodeFactory, getNodeType, getNullNode, getParameterTypes, getRowEstimate, getSchemaDescriptor, getSchemaDescriptor, getSPSName, getStatementType, getTableDescriptor, getTypeCompiler, init, init, init, init, init, init, init, init, init, init, init, isAtomic, isInstanceOf, isSessionSchema, isSessionSchema, makeConstantAction, makeResultDescription, makeTableName, needsSavepoint, nodeHeader, optimize, parseQueryText, printLabel, printSubNodes, referencesSessionSchema, resolveTableToSynonym, setBeginOffset, setContextManager, setEndOffset, setNodeType, setRefActionInfo, treePrint, treePrint, verifyClassExist

Methods inherited from class java.lang.Object

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

Field Detail

booleanValue

boolean booleanValue

unknownValue

boolean unknownValue

value

protected DataValueDescriptor value

Constructor Detail

BooleanConstantNode

public BooleanConstantNode()

Method Detail

init

public void init(java.lang.Object arg1)
          throws StandardException

Initializer for a BooleanConstantNode.

Overrides:

init in class QueryTreeNode

Parameters:

arg1 - A boolean containing the value of the constant

Throws:

StandardException

getConstantValueAsObject

java.lang.Object getConstantValueAsObject()

Return an Object representing the bind time value of this expression tree. If the expression tree does not evaluate to a constant at bind time then we return null. This is useful for bind time resolution of VTIs. RESOLVE: What do we do for primitives?

Overrides:

getConstantValueAsObject in class ValueNode

Returns:

An Object representing the bind time value of this expression tree. (null if not a bind time constant.)

getValueAsString

java.lang.String getValueAsString()

Return the value as a string.

Returns:

The value as a string.

isBooleanTrue

boolean isBooleanTrue()

Does this represent a true constant.

Overrides:

isBooleanTrue in class ValueNode

Returns:

Whether or not this node represents a true constant.

isBooleanFalse

boolean isBooleanFalse()

Does this represent a false constant.

Overrides:

isBooleanFalse in class ValueNode

Returns:

Whether or not this node represents a false constant.

selectivity

public double selectivity(Optimizable optTable)

The default selectivity for value nodes is 50%. This is overridden in specific cases, such as the RelationalOperators.

Overrides:

selectivity in class ValueNode

eliminateNots

ValueNode eliminateNots(boolean underNotNode)

Eliminate NotNodes in the current query block. We traverse the tree, inverting ANDs and ORs and eliminating NOTs as we go. We stop at ComparisonOperators and boolean expressions. We invert ComparisonOperators and replace boolean expressions with boolean expression = false. NOTE: Since we do not recurse under ComparisonOperators, there still could be NotNodes left in the tree.

Overrides:

eliminateNots in class ValueNode

Parameters:

underNotNode - Whether or not we are under a NotNode.

Returns:

The modified expression

generateConstant

void generateConstant(ExpressionClassBuilder acb,
                      MethodBuilder mb)

This generates the proper constant. It is implemented by every specific constant node (e.g. IntConstantNode).

Specified by:

generateConstant in class ConstantNode

Parameters:

acb - The ExpressionClassBuilder for the class being built

mb - The method the code to place the code

Returns:

The compiled Expression,

setValue

public void setValue(DataValueDescriptor value)

Set the value in this ConstantNode.

Overrides:

setValue in class ConstantNode

init

public void init(java.lang.Object typeId,
                 java.lang.Object nullable,
                 java.lang.Object maximumWidth)
          throws StandardException

Initializer for non-numeric types

Overrides:

init in class QueryTreeNode

Parameters:

typeId - The Type ID of the datatype

nullable - True means the constant is nullable

maximumWidth - The maximum number of bytes in the data value

Throws:

StandardException

getValue

public DataValueDescriptor getValue()

Get the value in this ConstantNode

toString

public java.lang.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

isCloneable

public boolean isCloneable()

Return whether or not this expression tree is cloneable.

Overrides:

isCloneable in class ValueNode

Returns:

boolean Whether or not this expression tree is cloneable.

getClone

public ValueNode getClone()

Return a clone of this node.

Overrides:

getClone in class ValueNode

Returns:

ValueNode A clone of this node.

bindExpression

public ValueNode bindExpression(FromList fromList,
                                SubqueryList subqueryList,
                                java.util.Vector aggregateVector)

Bind this expression. This means binding the sub-expressions, as well as figuring out what the return type is for this expression. In this case, there are no sub-expressions, and the return type is already known, so this is just a stub.

Overrides:

bindExpression in class ValueNode

Parameters:

fromList - The FROM list for the query this expression is in, for binding columns.

subqueryList - The subquery list being built as we find SubqueryNodes

aggregateVector - The aggregate vector being built as we find AggregateNodes

Returns:

The new top of the expression tree.

isConstantExpression

public boolean isConstantExpression()

Return whether or not this expression tree represents a constant expression.

Overrides:

isConstantExpression in class ValueNode

Returns:

Whether or not this expression tree represents a constant expression.

constantExpression

public boolean constantExpression(PredicateList whereClause)

Description copied from class: ValueNode

Return whether or not this expression tree represents a constant value. In this case, "constant" means that it will always evaluate to the same thing, even if it includes columns. A column is constant if it is compared to a constant expression.

Overrides:

constantExpression in class ValueNode

Returns:

True means this expression tree represents a constant value.

See Also:

ValueNode.constantExpression(org.apache.derby.impl.sql.compile.PredicateList)

generateExpression

public void generateExpression(ExpressionClassBuilder acb,
                               MethodBuilder mb)
                        throws StandardException

For a ConstantNode, we generate the equivalent literal value. A null is generated as a Null value cast to the type of the constant node. The subtypes of ConstantNode generate literal expressions for non-null values.

Overrides:

generateExpression in class ValueNode

Parameters:

acb - The ExpressionClassBuilder for the class being built

mb - The method the code to place the code

Returns:

The compiled Expression, if the constant is a null value, null if the constant is not a null value (confusing, huh?)

Throws:

StandardException - Thrown on error

isNull

public boolean isNull()

Return whether or not this node represents a typed null constant.

getOrderableVariantType

protected int getOrderableVariantType()

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 VARIANT - immutable

Overrides:

getOrderableVariantType in class ValueNode

Returns:

The variant type for the underlying expression.