Package net.sf.saxon.expr.flwor

Class ForClause

java.lang.Object

net.sf.saxon.expr.flwor.Clause

net.sf.saxon.expr.flwor.ForClause

public class ForClause
extends Clause

A "for" clause in a FLWOR expression

Nested Class Summary

Nested classes/interfaces inherited from class net.sf.saxon.expr.flwor.Clause

Clause.ClauseName

Field Summary

Fields

Modifier and Type	Field	Description
protected boolean	allowsEmpty
protected LocalVariableBinding	positionVariable
protected LocalVariableBinding	rangeVariable
protected Operand	sequenceOp
protected PullEvaluator	sequenceOperandEvaluator

Constructor Summary

Constructors

Constructor	Description
ForClause()

Method Summary

Modifier and Type	Method	Description
boolean	addPredicate(FLWORExpression flwor, ExpressionVisitor visitor, ContextItemStaticInfo contextItemType, Expression condition)	Convert where clause to a predicate.
void	addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet)	Collect information about the navigation paths followed by this clause, for document projection purposes
ForClause	copy(FLWORExpression flwor, RebindingMap rebindings)	Create a copy of this clause
void	explain(ExpressionPresenter out)	Diagnostic print of expression structure.
void	gatherVariableReferences(ExpressionVisitor visitor, Binding binding, java.util.List<VariableReference> references)	Build a list of all references to a variables declared in this clause
Clause.ClauseName	getClauseKey()	Get a keyword identifying what kind of clause this is
protected SequenceIterator	getIterator(XPathContext context)	Get an iterator over the items or members in the input sequence.
LocalVariableBinding	getPositionVariable()	Get the position variable (the variable bound by the "at" clause)
TuplePull	getPullStream(TuplePull base, XPathContext context)	Get a tuple stream that implements the functionality of this clause, taking its input from another tuple stream which this clause modifies
TuplePush	getPushStream(TuplePush destination, Outputter output, XPathContext context)	Get a push-mode tuple stream that implements the functionality of this clause, supplying its output to another tuple stream
LocalVariableBinding	getRangeVariable()	Get the range variable (the primary variable bound by this clause)
LocalVariableBinding[]	getRangeVariables()	Get the variables bound by this clause
Expression	getSequence()
Operand	getSequenceOp()
void	initSequence(FLWORExpression flwor, Expression sequence)
boolean	isAllowingEmpty()	Ask whether the "allowing empty" option is present
void	processOperands(OperandProcessor processor)	Process the subexpressions of this clause
void	refineVariableType(ExpressionVisitor visitor, java.util.List<VariableReference> references, Expression returnExpr)	Supply improved type information to the expressions that contain references to the variables declared in this clause
void	setAllowingEmpty(boolean option)	Say whether the "allowing empty" option is present
void	setPositionVariable(LocalVariableBinding binding)	Set the position variable (the variable bound by the "at" clause)
void	setRangeVariable(LocalVariableBinding binding)	Set the range variable (the primary variable bound by this clause)
void	setSequence(Expression sequence)
java.lang.String	toShortString()	Get a short string representation of the clause
java.lang.String	toString()
void	typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo)	Type-check the expression

Methods inherited from class net.sf.saxon.expr.flwor.Clause

containsNonInlineableVariableReference, getConfiguration, getLocation, getPackageData, getTraceInfo, isRepeated, optimize, setLocation, setPackageData, setRepeated

Methods inherited from class java.lang.Object

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

Field Detail

rangeVariable

protected LocalVariableBinding rangeVariable

positionVariable

protected LocalVariableBinding positionVariable

sequenceOp

protected Operand sequenceOp

sequenceOperandEvaluator

protected PullEvaluator sequenceOperandEvaluator

allowsEmpty

protected boolean allowsEmpty

Constructor Detail

ForClause

public ForClause()

Method Detail

getClauseKey

public Clause.ClauseName getClauseKey()

Description copied from class: Clause

Get a keyword identifying what kind of clause this is

Specified by:

getClauseKey in class Clause

Returns:

the kind of clause

copy

public ForClause copy(FLWORExpression flwor,
                      RebindingMap rebindings)

Description copied from class: Clause

Create a copy of this clause

Specified by:

copy in class Clause

Parameters:

flwor - the new FLWORExpression to contain the copied clause

rebindings - the rebinding map

Returns:

the copied clause

initSequence

public void initSequence(FLWORExpression flwor,
                         Expression sequence)

setSequence

public void setSequence(Expression sequence)

getSequence

public Expression getSequence()

getSequenceOp

public Operand getSequenceOp()

getIterator

protected SequenceIterator getIterator(XPathContext context)
                                throws XPathException

Get an iterator over the items or members in the input sequence.

Parameters:

context - dynamic evaluation context

Returns:

for a simple "for $x" clause, the sequence of items to which $x will be bound. For a "for member ¢x" clause, the sequence of array members, each wrapped as an object value

Throws:

XPathException - if evaluation fails

setRangeVariable

public void setRangeVariable(LocalVariableBinding binding)

Set the range variable (the primary variable bound by this clause)

Parameters:

binding - the range variable

getRangeVariable

public LocalVariableBinding getRangeVariable()

Get the range variable (the primary variable bound by this clause)

Returns:

the range variable

setPositionVariable

public void setPositionVariable(LocalVariableBinding binding)

Set the position variable (the variable bound by the "at" clause)

Parameters:

binding - the position variable, or null if there is no position variable

getPositionVariable

public LocalVariableBinding getPositionVariable()

Get the position variable (the variable bound by the "at" clause)

Returns:

the position variable, or null if there is no position variable

getRangeVariables

public LocalVariableBinding[] getRangeVariables()

Get the variables bound by this clause

Overrides:

getRangeVariables in class Clause

Returns:

the variable bindings (1 or 2 depending on whether there is a position variable)

setAllowingEmpty

public void setAllowingEmpty(boolean option)

Say whether the "allowing empty" option is present

Parameters:

option - true if the "allowing empty" option is present

isAllowingEmpty

public boolean isAllowingEmpty()

Ask whether the "allowing empty" option is present

Returns:

true if the "allowing empty" option is present

typeCheck

public void typeCheck(ExpressionVisitor visitor,
                      ContextItemStaticInfo contextInfo)
               throws XPathException

Type-check the expression

Overrides:

typeCheck in class Clause

Parameters:

visitor - the ExpressionVisitor, providing access to static context information

contextInfo - static information about the dynamic context

Throws:

XPathException - if any error is detected

getPullStream

public TuplePull getPullStream(TuplePull base,
                               XPathContext context)

Get a tuple stream that implements the functionality of this clause, taking its input from another tuple stream which this clause modifies

Specified by:

getPullStream in class Clause

Parameters:

base - the input tuple stream

context - the XPath dynamic context

Returns:

the output tuple stream

getPushStream

public TuplePush getPushStream(TuplePush destination,
                               Outputter output,
                               XPathContext context)

Get a push-mode tuple stream that implements the functionality of this clause, supplying its output to another tuple stream

Specified by:

getPushStream in class Clause

Parameters:

destination - the output tuple stream

output - the destination for the result

context - the dynamic evaluation context

Returns:

the push tuple stream that implements the functionality of this clause of the FLWOR expression

addPredicate

public boolean addPredicate(FLWORExpression flwor,
                            ExpressionVisitor visitor,
                            ContextItemStaticInfo contextItemType,
                            Expression condition)
                     throws XPathException

Convert where clause to a predicate.

Parameters:

flwor - the FLWOR expression (sans the relevant part of the where clause)

visitor - the expression visitor

contextItemType - the item type of the context item

condition - the predicate to be added. This will always be a single term (never a composite condition using "and"), as the where clause is split into separate terms before calling this method

Returns:

true if the expression has been changed, that is, if the where clause has been converted

Throws:

XPathException - if an error is encountered

processOperands

public void processOperands(OperandProcessor processor)
                     throws XPathException

Process the subexpressions of this clause

Specified by:

processOperands in class Clause

Parameters:

processor - the expression processor used to process the subexpressions

Throws:

XPathException - if any error is detected

gatherVariableReferences

public void gatherVariableReferences(ExpressionVisitor visitor,
                                     Binding binding,
                                     java.util.List<VariableReference> references)

Description copied from class: Clause

Build a list of all references to a variables declared in this clause

Overrides:

gatherVariableReferences in class Clause

Parameters:

visitor - the expression visitor

binding - a variable declared in this clause

references - the list of variable references, initially empty, to which the method will append

refineVariableType

public void refineVariableType(ExpressionVisitor visitor,
                               java.util.List<VariableReference> references,
                               Expression returnExpr)

Description copied from class: Clause

Supply improved type information to the expressions that contain references to the variables declared in this clause

Overrides:

refineVariableType in class Clause

Parameters:

visitor - the expression visitor

references - the list of variable references

returnExpr - the expression in the return clause

addToPathMap

public void addToPathMap(PathMap pathMap,
                         PathMap.PathMapNodeSet pathMapNodeSet)

Description copied from class: Clause

Collect information about the navigation paths followed by this clause, for document projection purposes

Specified by:

addToPathMap in class Clause

Parameters:

pathMap - the path map in which the data is to be collected

pathMapNodeSet - the path map node set representing the paths to the context item

explain

public void explain(ExpressionPresenter out)
             throws XPathException

Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.

Specified by:

explain in class Clause

Parameters:

out - the expression presenter used to display the structure

Throws:

XPathException - if any error occurs

toShortString

public java.lang.String toShortString()

Description copied from class: Clause

Get a short string representation of the clause

Overrides:

toShortString in class Clause

Returns:

a recognizable string

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object