net.sf.saxon.expr.flwor

Class Clause

java.lang.Object

net.sf.saxon.expr.flwor.Clause

Direct Known Subclasses:

CountClause, DiagnosticClause, ForClause, GroupByClause, LetClause, OrderByClause, TraceClause, WhereClause, WindowClause

public abstract class Clause
extends java.lang.Object

A "Clause" refers specifically to one of the clauses of a FLWOR expression, for example the "for" clause, the "let" clause, the "where" or "order by" clause. (The "return" clause, however, is not modelled as a Clause).

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Clause.ClauseName

Constructor Summary

Constructors

Constructor and Description
Clause()

Method Summary

Modifier and Type	Method and Description
abstract void	addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet) Collect information about the navigation paths followed by this clause, for document projection purposes
boolean	containsNonInlineableVariableReference(Binding binding) Determine whether the clause contains a reference to a local variable binding that cannot be inlined
abstract Clause	copy(FLWORExpression flwor, RebindingMap rebindings) Create a copy of this clause
abstract void	explain(ExpressionPresenter out) Diagnostic print of expression structure.
void	gatherVariableReferences(ExpressionVisitor visitor, Binding binding, java.util.List<VariableReference> refs) Build a list of all references to a variables declared in this clause
abstract Clause.ClauseName	getClauseKey() Get a keyword identifying what kind of clause this is
Configuration	getConfiguration()
Location	getLocation() Get the location, which can be used to determine the system ID and line number of the clause
PackageData	getPackageData()
abstract TuplePull	getPullStream(TuplePull base, XPathContext context) Get a pull-mode tuple stream that implements the functionality of this clause, taking its input from another tuple stream which this clause modifies
abstract 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[]	getRangeVariables() Get the variables bound by this clause
java.util.Map<java.lang.String,java.lang.Object>	getTraceInfo() Get information for inclusion in trace output
boolean	isRepeated()
void	optimize(ExpressionVisitor visitor, ContextItemStaticInfo contextItemType) Optimize any expressions contained within this clause
abstract 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	setLocation(Location locationId) Set the location, which can be used to determine the system ID and line number of the clause
void	setPackageData(PackageData pd)
void	setRepeated(boolean repeated)
java.lang.String	toShortString() Get a short string representation of the clause
void	typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) Type-check any expression contained within this clause

Methods inherited from class java.lang.Object

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

Constructor Detail

Clause

public Clause()

Method Detail

getLocation

public Location getLocation()

Get the location, which can be used to determine the system ID and line number of the clause

Returns:

the location

setLocation

public void setLocation(Location locationId)

Set the location, which can be used to determine the system ID and line number of the clause

Parameters:

locationId - the location

setPackageData

public void setPackageData(PackageData pd)

getPackageData

public PackageData getPackageData()

getConfiguration

public Configuration getConfiguration()

setRepeated

public void setRepeated(boolean repeated)

isRepeated

public boolean isRepeated()

copy

public abstract Clause copy(FLWORExpression flwor,
                            RebindingMap rebindings)

Create a copy of this clause

Parameters:

flwor - the new FLWORExpression to contain the copied clause

rebindings - the rebinding map

Returns:

the copied clause

optimize

public void optimize(ExpressionVisitor visitor,
                     ContextItemStaticInfo contextItemType)
              throws XPathException

Optimize any expressions contained within this clause

Parameters:

visitor - the ExpressionVisitor, providing access to static context information

contextItemType - the type of the context item

Throws:

XPathException - if any error is detected

typeCheck

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

Type-check any expression contained within this 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 abstract TuplePull getPullStream(TuplePull base,
                                        XPathContext context)

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

Parameters:

base - the input tuple stream

context - the dynamic evaluation context

Returns:

the output tuple stream

getPushStream

public abstract 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

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

processOperands

public abstract void processOperands(OperandProcessor processor)
                              throws XPathException

Process the subexpressions of this clause

Parameters:

processor - the expression processor used to process the subexpressions

Throws:

XPathException - if any error is detected

explain

public abstract void explain(ExpressionPresenter out)
                      throws XPathException

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

Parameters:

out - the expression presenter used to display the structure

Throws:

XPathException - if any error occurs

getRangeVariables

public LocalVariableBinding[] getRangeVariables()

Get the variables bound by this clause

Returns:

the variable bindings

gatherVariableReferences

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

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

Parameters:

visitor - the expression visitor

binding - a variable declared in this clause

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

containsNonInlineableVariableReference

public boolean containsNonInlineableVariableReference(Binding binding)

Determine whether the clause contains a reference to a local variable binding that cannot be inlined

Parameters:

binding - the binding for the local variable in question

Returns:

true if this clause uses the variable in a way that does not permit inlining

refineVariableType

public 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

Parameters:

visitor - the expression visitor

references - the list of variable references

returnExpr - the expression in the return clause

addToPathMap

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

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

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

getClauseKey

public abstract Clause.ClauseName getClauseKey()

Get a keyword identifying what kind of clause this is

Returns:

the kind of clause

toShortString

public java.lang.String toShortString()

Get a short string representation of the clause

Returns:

a recognizable string

getTraceInfo

public java.util.Map<java.lang.String,java.lang.Object> getTraceInfo()

Get information for inclusion in trace output

Returns:

a map containing the properties to be output