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

Field Summary

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

COUNT, FOR, GROUPBYCLAUSE, LET, ORDERBYCLAUSE, WHERE, WINDOW

Constructor Summary

ForClause()

Method Summary

boolean	addPredicate(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType, Expression condition) Convert where clause to a predicate.
ForClause	copy()
void	explain(ExpressionPresenter out) Diagnostic print of expression structure.
void	gatherVariableReferences(ExpressionVisitor visitor, Binding binding, List<VariableReference> references) Build a list of all references to a variables declared in this clause
void	gatherVariableReferences(List references)
int	getClauseKey() Get a keyword identifying what kind of clause this is
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, 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 number of variables bound by this clause
Expression	getSequence() Get the expression over which the "for" variable iterates
boolean	isAllowingEmpty() Ask whether the "allowing empty" option is present
void	processSubExpressions(ExpressionProcessor processor) Process the subexpressions of this clause
void	refineVariableType(ExpressionVisitor visitor, 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) Set the expression over which the "for" variable iterates
String	toString()
void	typeCheck(ExpressionVisitor visitor) Type-check the expression

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

optimize

Methods inherited from class java.lang.Object

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

Constructor Detail

ForClause

public ForClause()

Method Detail

getClauseKey

public int 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()

Specified by:

copy in class Clause

setSequence

public void setSequence(Expression sequence)

Set the expression over which the "for" variable iterates

Parameters:

sequence - the expression over which the variable ranges

getSequence

public Expression getSequence()

Get the expression over which the "for" variable iterates

Returns:

the expression over which the variable ranges

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

getPositionVariable

public LocalVariableBinding getPositionVariable()

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

Returns:

the position variable

getRangeVariables

public LocalVariableBinding[] getRangeVariables()

Get the number of variables bound by this clause

Overrides:

getRangeVariables in class Clause

Returns:

the number of 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)
               throws XPathException

Type-check the expression

Overrides:

typeCheck in class Clause

Parameters:

visitor - the ExpressionVisitor, providing access to static context information

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,
                               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

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(ExpressionVisitor visitor,
                            ExpressionVisitor.ContextItemType contextItemType,
                            Expression condition)
                     throws XPathException

Convert where clause to a predicate.

Parameters:

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

processSubExpressions

public void processSubExpressions(ExpressionProcessor processor)
                           throws XPathException

Process the subexpressions of this clause

Specified by:

processSubExpressions in class Clause

Parameters:

processor - the expression processor used to process the subexpressions

Throws:

XPathException - if any error is detected

gatherVariableReferences

public void gatherVariableReferences(List references)

gatherVariableReferences

public void gatherVariableReferences(ExpressionVisitor visitor,
                                     Binding binding,
                                     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,
                               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

explain

public void explain(ExpressionPresenter out)

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

toString

public String toString()

Overrides:

toString in class Object