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

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

All Implemented Interfaces:

Visitable

public class CastNode

extends ValueNode

An CastNode represents a cast expressionr.

Author:

Jerry Brenner

Field Summary

(package private) ValueNode	castOperand
(package private) DataTypeDescriptor	castTarget
(package private) TypeId	destCTI
(package private) boolean	forDataTypeFunction
(package private) TypeId	sourceCTI
(package private) int	targetCharType

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

CastNode()

Method Summary

Visitable	accept(Visitor v) Accept a visitor, and call v.visit() on child nodes as necessary.
void	bindCastNodeOnly() Bind this node but not its child.
ValueNode	bindExpression(FromList fromList, SubqueryList subqueryList, java.util.Vector aggregateVector) Bind this expression.
(package private) void	bindParameter() By default unary operators don't accept ?
boolean	categorize(JBitSet referencedTabs, boolean simplePredsOnly) Categorize this predicate.
boolean	constantExpression(PredicateList whereClause) Return whether or not this expression tree represents a constant value.
private void	genDataValueConversion(ExpressionClassBuilder acb, MethodBuilder mb)
void	generateExpression(ExpressionClassBuilder acb, MethodBuilder mb) Do code generation for this unary operator.
private ValueNode	getCastFromCharConstant(int destJDBCTypeId) Get a constant representing the cast from a CHAR to another type.
private ValueNode	getCastFromIntegralType(long longValue, int destJDBCTypeId) Get a constant representing the cast from an integral type to another type.
private ValueNode	getCastFromNumericType(DataValueDescriptor constantValue, int destJDBCTypeId) Get a constant representing the cast from a non-integral type to another type.
(package private) java.lang.Object	getConstantValueAsObject() Return an Object representing the bind time value of this expression tree.
boolean	getForDataTypeFunction() is this a cast node for a data type scalar function?
protected int	getOrderableVariantType() Return the variant type for the underlying expression.
void	init(java.lang.Object castOperand, java.lang.Object castTarget) Initializer for a CastNode
void	init(java.lang.Object castOperand, java.lang.Object charType, java.lang.Object charLength) Initializer for a CastNode
boolean	isConstantExpression() Return whether or not this expression tree represents a constant expression.
ValueNode	preprocess(int numTables, FromList outerFromList, SubqueryList outerSubqueryList, PredicateList outerPredicateList) Preprocess an expression tree.
void	printSubNodes(int depth) Prints the sub-nodes of this object.
ValueNode	remapColumnReferencesToExpressions() Remap all ColumnReferences in this tree to be clones of the underlying expression.
void	setClause(int clause) Set the clause that this node appears in.
void	setForDataTypeFunction(boolean b) set this to be a dataTypeScalarFunction
java.lang.String	toString() Convert this object to a String.

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

bindExpression, changeToCNF, checkIsBoolean, checkReliability, checkReliability, checkTopPredicatesForEqualsConditions, copyFields, eliminateNots, genEqualsFalseTree, generate, generateFilter, genIsNullTree, genSQLJavaSQLTree, getClause, getClone, getColumnName, getDataValueFactory, getSchemaName, getSourceResultColumn, getTableName, getTablesReferenced, getTransformed, getTypeCompiler, getTypeId, getTypeServices, init, isBinaryEqualsOperatorNode, isBooleanFalse, isBooleanTrue, isCloneable, isParameterNode, isRelationalOperator, optimizableEqualityNode, putAndsOnTop, selectivity, setDescriptor, setTransformed, setType, updatableByCursor, verifyChangeToCNF, verifyEliminateNots, verifyPutAndsOnTop

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

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, 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

castTarget

DataTypeDescriptor castTarget

castOperand

ValueNode castOperand

targetCharType

int targetCharType

destCTI

TypeId destCTI

sourceCTI

TypeId sourceCTI

forDataTypeFunction

boolean forDataTypeFunction

Constructor Detail

CastNode

public CastNode()

Method Detail

init

public void init(java.lang.Object castOperand,
                 java.lang.Object castTarget)
          throws StandardException

Initializer for a CastNode

Overrides:

init in class QueryTreeNode

Parameters:

castOperand - The operand of the node

castTarget - DataTypeServices (target type of cast)

Throws:

StandardException - Thrown on error

init

public void init(java.lang.Object castOperand,
                 java.lang.Object charType,
                 java.lang.Object charLength)
          throws StandardException

Initializer for a CastNode

Overrides:

init in class QueryTreeNode

Parameters:

castOperand - The operand of the node

charType - CHAR or VARCHAR JDBC type as target

charLength - target type length

Throws:

StandardException - Thrown on error

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

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

Returns:

Nothing

getOrderableVariantType

protected int getOrderableVariantType()
                               throws StandardException

Description copied from class: ValueNode

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 expressions)

Overrides:

getOrderableVariantType in class ValueNode

Returns:

The variant type for the underlying expression.

Throws:

StandardException - Thrown on error

setClause

public void setClause(int clause)

Set the clause that this node appears in.

Overrides:

setClause in class ValueNode

Parameters:

clause - The clause that this node appears in.

Returns:

Nothing.

bindExpression

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

Bind this expression. This means binding the sub-expressions, as well as figuring out what the return type is for this expression.

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.

Throws:

StandardException - Thrown on error

bindCastNodeOnly

public void bindCastNodeOnly()
                      throws StandardException

Bind this node but not its child. Caller has already bound the child. This is useful for when we generate a CastNode during binding after having already bound the child.

Returns:

Nothing

Throws:

StandardException - Thrown on error

getCastFromCharConstant

private ValueNode getCastFromCharConstant(int destJDBCTypeId)
                                   throws StandardException

Get a constant representing the cast from a CHAR to another type. If this is not an "easy" cast to perform, then just return this cast node. Here's what we think is "easy": source destination ------ ----------- char boolean char date/time/ts char non-decimal numeric

Parameters:

destJDBCTypeId - The destination JDBC TypeId

Returns:

The new top of the tree (this CastNode or a new Constant)

Throws:

StandardException - Thrown on error

getCastFromIntegralType

private ValueNode getCastFromIntegralType(long longValue,
                                          int destJDBCTypeId)
                                   throws StandardException

Get a constant representing the cast from an integral type to another type. If this is not an "easy" cast to perform, then just return this cast node. Here's what we think is "easy": source destination ------ ----------- integral type non-decimal numeric integral type char

Parameters:

longValue - integral type as a long to cast from

destJDBCTypeId - The destination JDBC TypeId

Returns:

The new top of the tree (this CastNode or a new Constant)

Throws:

StandardException - Thrown on error

getCastFromNumericType

private ValueNode getCastFromNumericType(DataValueDescriptor constantValue,
                                         int destJDBCTypeId)
                                  throws StandardException

Get a constant representing the cast from a non-integral type to another type. If this is not an "easy" cast to perform, then just return this cast node. Here's what we think is "easy": source destination ------ ----------- non-integral type non-decimal numeric non-integral type char

Parameters:

destJDBCTypeId - The destination JDBC TypeId

Returns:

The new top of the tree (this CastNode or a new Constant)

Throws:

StandardException - Thrown on error

preprocess

public ValueNode preprocess(int numTables,
                            FromList outerFromList,
                            SubqueryList outerSubqueryList,
                            PredicateList outerPredicateList)
                     throws StandardException

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.

Overrides:

preprocess in class ValueNode

Parameters:

numTables - Number of tables in the DML Statement

outerFromList - FromList from outer query block

outerSubqueryList - SubqueryList from outer query block

outerPredicateList - PredicateList from outer query block

Returns:

The modified expression

Throws:

StandardException - Thrown on error

categorize

public boolean categorize(JBitSet referencedTabs,
                          boolean simplePredsOnly)
                   throws StandardException

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.

Overrides:

categorize in class ValueNode

Parameters:

referencedTabs - JBitSet with bit map of referenced FromTables

simplePredsOnly - Whether or not to consider method calls, field references and conditional nodes when building bit map

Returns:

boolean Whether or not source.expression is a ColumnReference or a VirtualColumnNode.

Throws:

StandardException - Thrown on error

remapColumnReferencesToExpressions

public ValueNode remapColumnReferencesToExpressions()
                                             throws StandardException

Remap all ColumnReferences in this tree to be clones of the underlying expression.

Overrides:

remapColumnReferencesToExpressions in class ValueNode

Returns:

ValueNode The remapped expression tree.

Throws:

StandardException - Thrown on error

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)

bindParameter

void bindParameter()
             throws StandardException

By default unary operators don't accept ? parameters as operands. This can be over-ridden for particular unary operators.

Returns:

Nothing

Throws:

StandardException - Always thrown to indicate a ? parameter where it isn't allowed.

getConstantValueAsObject

java.lang.Object getConstantValueAsObject()
                                    throws StandardException

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.)

Throws:

StandardException - Thrown on error

generateExpression

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

Do code generation for this unary operator.

Overrides:

generateExpression in class ValueNode

Parameters:

acb - The ExpressionClassBuilder for the class we're generating

mb - The method the code to place the code

Returns:

An expression to evaluate this operator

Throws:

StandardException - Thrown on error

genDataValueConversion

private void genDataValueConversion(ExpressionClassBuilder acb,
                                    MethodBuilder mb)
                             throws StandardException

Throws:

StandardException

accept

public Visitable accept(Visitor v)
                 throws StandardException

Accept a visitor, and call v.visit() on child nodes as necessary.

Specified by:

accept in interface Visitable

Overrides:

accept in class QueryTreeNode

Parameters:

v - the visitor

Throws:

StandardException - on error

setForDataTypeFunction

public void setForDataTypeFunction(boolean b)

set this to be a dataTypeScalarFunction

Parameters:

b - true to use function conversion rules

getForDataTypeFunction

public boolean getForDataTypeFunction()

is this a cast node for a data type scalar function?

Returns:

true if this is a function, false for regular cast node