Package net.sf.saxon.expr.flwor

Class WindowClause

java.lang.Object

net.sf.saxon.expr.flwor.Clause

net.sf.saxon.expr.flwor.WindowClause

public class WindowClause
extends Clause

Implements an XQuery 3.0 sliding or tumbling window clause within a FLWOR expression

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected static class	WindowClause.Window	Information about a window: the items making up the window, as well as the variables relating to the start and end of the window, and the status of the winoow in relation to the processing of the current input sequence.

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

Clause.ClauseName

Field Summary

Fields

Modifier and Type	Field	Description
static int	END_ITEM
static int	END_ITEM_POSITION
static int	END_NEXT_ITEM
static int	END_PREVIOUS_ITEM
static int	START_ITEM
static int	START_ITEM_POSITION
static int	START_NEXT_ITEM
static int	START_PREVIOUS_ITEM
static int	WINDOW_VAR

Constructor Summary

Constructors

Constructor	Description
WindowClause()

Method Summary

Modifier and Type	Method	Description
void	addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet)	Collect information about the navigation paths followed by this clause, for document projection purposes
protected void	checkWindowContents(WindowClause.Window w)
Clause	copy(FLWORExpression flwor, RebindingMap rebindings)	Create a copy of this clause
void	explain(ExpressionPresenter out)	Diagnostic print of expression structure.
Clause.ClauseName	getClauseKey()	Get a keyword identifying what kind of clause this is
Expression	getEndCondition()
ItemTypeCheckingFunction	getItemTypeChecker()
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
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
Expression	getSequence()
Expression	getStartCondition()
LocalVariableBinding	getVariableBinding(int role)
void	initEndCondition(FLWORExpression flwor, Expression endCondition)
void	initSequence(FLWORExpression flwor, Expression sequence)
void	initStartCondition(FLWORExpression flwor, Expression startCondition)
boolean	isIncludeUnclosedWindows()	Ask whether windows that are unclosed at the end of the sequence should be included in the result
boolean	isSlidingWindow()	Ask whether this is a sliding or tumbling window
boolean	isTumblingWindow()	Ask whether this is a sliding or tumbling window
boolean	isWindowMustBeSingleton()
protected static Sequence	makeValue(Item item)
protected boolean	matchesEnd(WindowClause.Window window, Item previous, Item current, Item next, int position, XPathContext context)	Determine whether the current item is the last item in a window
protected boolean	matchesStart(Item previous, Item current, Item next, int position, XPathContext context)	Determine whether the current item is the start of a new window
void	processOperands(OperandProcessor processor)	Process the subexpressions of this clause
void	setEndCondition(Expression endCondition)
void	setIncludeUnclosedWindows(boolean include)	Say whether windows that are unclosed at the end of the sequence should be included in the result
void	setIsSlidingWindow(boolean sliding)	Say whether this is a sliding or tumbling window
void	setSequence(Expression sequence)
void	setStartCondition(Expression startCondition)
void	setVariableBinding(int role, LocalVariableBinding binding)
void	typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo)	Type-check any expression contained within this clause

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

containsNonInlineableVariableReference, gatherVariableReferences, getConfiguration, getLocation, getPackageData, getTraceInfo, isRepeated, optimize, refineVariableType, setLocation, setPackageData, setRepeated, toShortString

Methods inherited from class java.lang.Object

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

Field Detail

WINDOW_VAR

public static final int WINDOW_VAR

See Also:

Constant Field Values

START_ITEM

public static final int START_ITEM

See Also:

Constant Field Values

START_ITEM_POSITION

public static final int START_ITEM_POSITION

See Also:

Constant Field Values

START_PREVIOUS_ITEM

public static final int START_PREVIOUS_ITEM

See Also:

Constant Field Values

START_NEXT_ITEM

public static final int START_NEXT_ITEM

See Also:

Constant Field Values

END_ITEM

public static final int END_ITEM

See Also:

Constant Field Values

END_ITEM_POSITION

public static final int END_ITEM_POSITION

See Also:

Constant Field Values

END_PREVIOUS_ITEM

public static final int END_PREVIOUS_ITEM

See Also:

Constant Field Values

END_NEXT_ITEM

public static final int END_NEXT_ITEM

See Also:

Constant Field Values

Constructor Detail

WindowClause

public WindowClause()

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

setIsSlidingWindow

public void setIsSlidingWindow(boolean sliding)

Say whether this is a sliding or tumbling window

Parameters:

sliding - true if this is a sliding window, false for a tumbling window

isSlidingWindow

public boolean isSlidingWindow()

Ask whether this is a sliding or tumbling window

Returns:

true if this is a sliding window, false for a tumbling window

isTumblingWindow

public boolean isTumblingWindow()

Ask whether this is a sliding or tumbling window

Returns:

false if this is a sliding window, true for a tumbling window

setIncludeUnclosedWindows

public void setIncludeUnclosedWindows(boolean include)

Say whether windows that are unclosed at the end of the sequence should be included in the result

Parameters:

include - true if unclosed windows are to be included in the result

isIncludeUnclosedWindows

public boolean isIncludeUnclosedWindows()

Ask whether windows that are unclosed at the end of the sequence should be included in the result

Returns:

true if unclosed windows are to be included in the result

initSequence

public void initSequence(FLWORExpression flwor,
                         Expression sequence)

setSequence

public void setSequence(Expression sequence)

getSequence

public Expression getSequence()

initStartCondition

public void initStartCondition(FLWORExpression flwor,
                               Expression startCondition)

setStartCondition

public void setStartCondition(Expression startCondition)

getStartCondition

public Expression getStartCondition()

initEndCondition

public void initEndCondition(FLWORExpression flwor,
                             Expression endCondition)

setEndCondition

public void setEndCondition(Expression endCondition)

getEndCondition

public Expression getEndCondition()

setVariableBinding

public void setVariableBinding(int role,
                               LocalVariableBinding binding)
                        throws XPathException

Throws:

XPathException

getVariableBinding

public LocalVariableBinding getVariableBinding(int role)

getItemTypeChecker

public ItemTypeCheckingFunction getItemTypeChecker()

isWindowMustBeSingleton

public boolean isWindowMustBeSingleton()

typeCheck

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

Description copied from class: Clause

Type-check any expression contained within this clause

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

checkWindowContents

protected void checkWindowContents(WindowClause.Window w)
                            throws XPathException

Throws:

XPathException

copy

public Clause 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

getPullStream

public 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

Specified by:

getPullStream in class Clause

Parameters:

base - the input tuple stream

context - the dynamic evaluation 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

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

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

getRangeVariables

public LocalVariableBinding[] getRangeVariables()

Get the variables bound by this clause

Overrides:

getRangeVariables in class Clause

Returns:

the variable bindings

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

matchesStart

protected boolean matchesStart(Item previous,
                               Item current,
                               Item next,
                               int position,
                               XPathContext context)
                        throws XPathException

Determine whether the current item is the start of a new window

Parameters:

previous - the item before the current item (null if the current item is the first)

current - the current item

next - the item after the current item (null if the current item is the last)

position - the position of the current item in the input sequence

context - the dynamic evaluation context

Returns:

true if the current item forms the start of a new window

Throws:

XPathException - if a failure occurs evaluating the conditions

matchesEnd

protected boolean matchesEnd(WindowClause.Window window,
                             Item previous,
                             Item current,
                             Item next,
                             int position,
                             XPathContext context)
                      throws XPathException

Determine whether the current item is the last item in a window

Parameters:

window - the window in question

previous - the item before the current item (null if the current item is the first)

current - the current item

next - the item after the current item (null if the current item is the last)

position - the position of the current item in the input sequence

context - the dynamic evaluation context

Returns:

true if the current item is the last item in the specified window

Throws:

XPathException - if a failure occurs evaluating the conditions

makeValue

protected static Sequence makeValue(Item item)