net.sf.saxon.expr.instruct

Class ApplyTemplates

java.lang.Object

net.sf.saxon.expr.Expression

net.sf.saxon.expr.instruct.Instruction

net.sf.saxon.expr.instruct.ApplyTemplates

All Implemented Interfaces:

SourceLocator, ITemplateCall, TailCallReturner, IdentityComparable, InstructionInfo

Direct Known Subclasses:

MultithreadedApplyTemplates, StreamingApplyTemplates

public class ApplyTemplates
extends Instruction
implements ITemplateCall

An instruction representing an xsl:apply-templates element in the stylesheet

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	ApplyTemplates.ApplyTemplatesPackage An ApplyTemplatesPackage is an object that encapsulates the sequence of nodes to be processed, the mode, the parameters to be supplied, and the execution context.

Field Summary

Fields

Modifier and Type	Field and Description
protected WithParam[]	actualParams
protected boolean	implicitSelect
protected Mode	mode
protected RuleManager	ruleManager
protected Expression	select
protected Expression	threads
protected WithParam[]	tunnelParams
protected boolean	useCurrentMode
protected boolean	useTailRecursion

Fields inherited from class net.sf.saxon.expr.Expression

EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, locationId, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, PROCESS_METHOD, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, WATCH_METHOD

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	ApplyTemplates()
	ApplyTemplates(Expression select, boolean useCurrentMode, boolean useTailRecursion, boolean implicitSelect, Mode mode, RuleManager ruleManager, Expression threads) Construct an apply-templates instructino

Method Summary

Methods

Modifier and Type	Method and Description
PathMap.PathMapNodeSet	addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet) Add a representation of this expression to a PathMap.
protected TailCall	apply(XPathContext context, boolean returnTailCall)
Expression	copy() Copy an expression.
boolean	createsNewNodes() Determine whether this instruction creates new nodes.
void	explain(ExpressionPresenter out) Diagnostic print of expression structure.
protected void	explainStreaming(ExpressionPresenter out)
WithParam[]	getActualParams() Get the actual parameters passed to the called template
ExpressionCompiler	getExpressionCompiler() Return the compiler of the ApplyTemplates expression
int	getImplementationMethod() An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process().
int	getInstructionNameCode() Get the name of this instruction for diagnostic and tracing purposes
int	getIntrinsicDependencies() Determine the intrinsic dependencies of an expression, that is, those which are not derived from the dependencies of its subexpressions.
Mode	getMode() Get the Mode
Expression	getNumberOfThreadsExpression() Get the number of threads requested
RuleManager	getRuleManager()
Expression	getSelectExpression() Get the select expression
ApplyTemplatesAdjunct	getStreamingAdjunct() Get a class that supports streamed evaluation of this expression
WithParam[]	getTunnelParams() Get the tunnel parameters passed to the called template
protected void	init(Expression select, boolean useCurrentMode, boolean useTailRecursion, Mode mode)
boolean	isImplicitSelect() Ask if the select expression was implicit
Iterable<Operand>	operands() Get the immediate sub-expressions of this expression, with information about the relationship of each expression to its parent expression.
Expression	optimize(ExpressionVisitor visitor, ContextItemStaticInfo contextItemType) Perform optimisation of an expression and its subexpressions.
void	process(XPathContext context) Process the instruction, without returning any tail calls
TailCall	processLeavingTail(XPathContext context) ProcessLeavingTail: called to do the real work of this instruction.
protected void	promoteInst(PromotionOffer offer) Handle promotion offers, that is, non-local tree rewrites.
boolean	replaceOperand(Expression original, Expression replacement) Replace one subexpression by a replacement subexpression
void	setActualParameters(WithParam[] actualParams, WithParam[] tunnelParams) Set the actual parameters on the call
Expression	simplify(ExpressionVisitor visitor) Simplify an expression.
Expression	typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) Perform type checking of an expression and its subexpressions.
boolean	usesCurrentMode() Ask if mode="#current" was specified
boolean	useTailRecursion() Ask if tail recursion is to be used

Methods inherited from class net.sf.saxon.expr.instruct.Instruction

assembleParams, assembleTunnelParams, computeCardinality, computeSpecialProperties, dynamicError, evaluateAsString, evaluateItem, getConstructType, getExpressionName, getInstructionName, getItemType, getIteratorFromProcessMethod, getSourceLocator, isXSLT, iterate, promote, toStreamingPattern

Methods inherited from class net.sf.saxon.expr.Expression

adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, clearStreamabilityData, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluatePendingUpdates, explain, getCardinality, getColumnNumber, getConfiguration, getContainer, getDependencies, getEvaluationMethod, getHostLanguage, getIntegerBounds, getLineNumber, getLocationId, getObjectName, getPosture, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getStreamability, getSweep, getSystemId, hasVariableBinding, identityHashCode, implementsStaticTypeCheck, isIdentical, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterateEvents, makeStreamingAdjunct, markTailFunctionCalls, operandList, resetLocalStaticProperties, setContainer, setEvaluationMethod, setFiltered, setFlattened, setLocationId, setPostureAndSweep, staticTypeCheck, suppressValidation, toPattern, toShortString, toString, typeError, unordered

Methods inherited from class java.lang.Object

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

Methods inherited from interface javax.xml.transform.SourceLocator

getColumnNumber, getLineNumber, getPublicId, getSystemId

Field Detail

select

protected Expression select

actualParams

protected WithParam[] actualParams

tunnelParams

protected WithParam[] tunnelParams

useCurrentMode

protected boolean useCurrentMode

useTailRecursion

protected boolean useTailRecursion

mode

protected Mode mode

implicitSelect

protected boolean implicitSelect

threads

protected Expression threads

ruleManager

protected RuleManager ruleManager

Constructor Detail

ApplyTemplates

protected ApplyTemplates()

ApplyTemplates

public ApplyTemplates(Expression select,
              boolean useCurrentMode,
              boolean useTailRecursion,
              boolean implicitSelect,
              Mode mode,
              RuleManager ruleManager,
              Expression threads)

Construct an apply-templates instructino

Parameters:

select - the select expression

useCurrentMode - true if mode="#current" was specified

useTailRecursion - true if this instruction is the last in its template

implicitSelect - true if the select expression is implicit, that is, if there was no explicit select expression in the call. This information is used only to make error messages more meaningful.

mode - the mode specified on apply-templates

threads - expression whose value indicates how many threads to use when multithreading

Method Detail

init

protected void init(Expression select,
        boolean useCurrentMode,
        boolean useTailRecursion,
        Mode mode)

setActualParameters

public void setActualParameters(WithParam[] actualParams,
                       WithParam[] tunnelParams)

Set the actual parameters on the call

Parameters:

actualParams - represents the contained xsl:with-param elements having tunnel="no" (the default)

tunnelParams - represents the contained xsl:with-param elements having tunnel="yes"

getInstructionNameCode

public int getInstructionNameCode()

Get the name of this instruction for diagnostic and tracing purposes

Overrides:

getInstructionNameCode in class Instruction

Returns:

a code identifying the instruction: typically but not always the fingerprint of a name in the XSLT namespace

getImplementationMethod

public int getImplementationMethod()

An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process(). This method indicates which of these methods is prefered. For instructions this is the process() method.

Overrides:

getImplementationMethod in class Instruction

Returns:

the implementation method, for example Expression.ITERATE_METHOD or Expression.EVALUATE_METHOD or Expression.PROCESS_METHOD

getNumberOfThreadsExpression

public Expression getNumberOfThreadsExpression()

Get the number of threads requested

Returns:

the value of the saxon:threads attribute

simplify

public Expression simplify(ExpressionVisitor visitor)
                    throws XPathException

Simplify an expression. This performs any static optimization (by rewriting the expression as a different expression).

Overrides:

simplify in class Expression

Parameters:

visitor - the expression visitor

Returns:

the simplified expression

Throws:

XPathException - if an error is discovered during expression rewriting

typeCheck

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

Description copied from class: Expression

Perform type checking of an expression and its subexpressions. This is the second phase of static optimization.

This checks statically that the operands of the expression have the correct type; if necessary it generates code to do run-time type checking or type conversion. A static type error is reported only if execution cannot possibly succeed, that is, if a run-time type error is inevitable. The call may return a modified form of the expression.

This method is called after all references to functions and variables have been resolved to the declaration of the function or variable. However, the types of such functions and variables may not be accurately known if they have not been explicitly declared.

If the implementation returns a value other than "this", then it is required to ensure that the location information in the returned expression have been set up correctly. It should not rely on the caller to do this, although for historical reasons many callers do so.

Overrides:

typeCheck in class Expression

Parameters:

visitor - an expression visitor

contextInfo - Information available statically about the context item: whether it is (possibly) absent; its static type; its streaming posture.

Returns:

the original expression, rewritten to perform necessary run-time type checks, and to perform other type-related optimizations

Throws:

XPathException - if an error is discovered during this phase (typically a type error)

optimize

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

Description copied from class: Expression

Perform optimisation of an expression and its subexpressions. This is the third and final phase of static optimization.

This method is called after all references to functions and variables have been resolved to the declaration of the function or variable, and after all type checking has been done.

Overrides:

optimize in class Expression

Parameters:

visitor - an expression visitor

contextItemType - the static type of "." at the point where this expression is invoked. The parameter is set to null if it is known statically that the context item will be undefined. If the type of the context item is not known statically, the argument is set to Type.ITEM_TYPE

Returns:

the original expression, rewritten if appropriate to optimize execution

Throws:

XPathException - if an error is discovered during this phase (typically a type error)

getIntrinsicDependencies

public int getIntrinsicDependencies()

Description copied from class: Expression

Determine the intrinsic dependencies of an expression, that is, those which are not derived from the dependencies of its subexpressions. For example, position() has an intrinsic dependency on the context position, while (position()+1) does not. The default implementation of the method returns 0, indicating "no dependencies".

Overrides:

getIntrinsicDependencies in class Expression

Returns:

a set of bit-significant flags identifying the "intrinsic" dependencies. The flags are documented in class net.sf.saxon.value.StaticProperty

getRuleManager

public RuleManager getRuleManager()

copy

public Expression copy()

Copy an expression. This makes a deep copy.

Specified by:

copy in class Expression

Returns:

the copy of the original expression

createsNewNodes

public final boolean createsNewNodes()

Determine whether this instruction creates new nodes. This implementation returns true (which is almost invariably the case, so it's not worth doing any further analysis to find out more precisely).

Overrides:

createsNewNodes in class Instruction

Returns:

true if the instruction creates new nodes (or if it can't be proved that it doesn't)

process

public void process(XPathContext context)
             throws XPathException

Description copied from class: Instruction

Process the instruction, without returning any tail calls

Overrides:

process in class Instruction

Parameters:

context - The dynamic context, giving access to the current node, the current variables, etc.

Throws:

XPathException - if a dynamic error occurs

processLeavingTail

public TailCall processLeavingTail(XPathContext context)
                            throws XPathException

Description copied from class: Instruction

ProcessLeavingTail: called to do the real work of this instruction. This method must be implemented in each subclass. The results of the instruction are written to the current Receiver, which can be obtained via the Controller.

Specified by:

processLeavingTail in interface TailCallReturner

Specified by:

processLeavingTail in class Instruction

Parameters:

context - The dynamic context of the transformation, giving access to the current node, the current variables, etc.

Returns:

null if the instruction has completed execution; or a TailCall indicating a function call or template call that is delegated to the caller, to be made after the stack has been unwound so as to save stack space.

Throws:

XPathException - if a dynamic error occurs during the evaluation of the instruction

apply

protected TailCall apply(XPathContext context,
             boolean returnTailCall)
                  throws XPathException

Throws:

XPathException

operands

public Iterable<Operand> operands()

Description copied from class: Expression

Get the immediate sub-expressions of this expression, with information about the relationship of each expression to its parent expression. Default implementation works off the results of iterateSubExpressions()

If the expression is a Callable, then it is required that the order of the operands returned by this function is the same as the order of arguments supplied to the corresponding call() method.

Overrides:

operands in class Expression

Returns:

an iterator containing the sub-expressions of this expression

replaceOperand

public boolean replaceOperand(Expression original,
                     Expression replacement)

Replace one subexpression by a replacement subexpression

Overrides:

replaceOperand in class Expression

Parameters:

original - the original subexpression

replacement - the replacement subexpression

Returns:

true if the original subexpression is found

getSelectExpression

public Expression getSelectExpression()

Get the select expression

Returns:

the select expression

isImplicitSelect

public boolean isImplicitSelect()

Ask if the select expression was implicit

Returns:

true if no select attribute was explicitly specified

useTailRecursion

public boolean useTailRecursion()

Ask if tail recursion is to be used

Returns:

true if tail recursion is used

usesCurrentMode

public boolean usesCurrentMode()

Ask if mode="#current" was specified

Returns:

true if mode="#current" was specified

getMode

public Mode getMode()

Get the Mode

Returns:

the mode, or null if mode="#current" was specified

getActualParams

public WithParam[] getActualParams()

Get the actual parameters passed to the called template

Specified by:

getActualParams in interface ITemplateCall

Returns:

the non-tunnel parameters

getTunnelParams

public WithParam[] getTunnelParams()

Get the tunnel parameters passed to the called template

Specified by:

getTunnelParams in interface ITemplateCall

Returns:

the tunnel parameters

promoteInst

protected void promoteInst(PromotionOffer offer)
                    throws XPathException

Handle promotion offers, that is, non-local tree rewrites.

Overrides:

promoteInst in class Instruction

Parameters:

offer - The type of rewrite being offered

Throws:

XPathException

addToPathMap

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

Add a representation of this expression to a PathMap. The PathMap captures a map of the nodes visited by an expression in a source tree.

The default implementation of this method assumes that an expression does no navigation other than the navigation done by evaluating its subexpressions, and that the subexpressions are evaluated in the same context as the containing expression. The method must be overridden for any expression where these assumptions do not hold. For example, implementations exist for AxisExpression, ParentExpression, and RootExpression (because they perform navigation), and for the doc(), document(), and collection() functions because they create a new navigation root. Implementations also exist for PathExpression and FilterExpression because they have subexpressions that are evaluated in a different context from the calling expression.

Overrides:

addToPathMap in class Expression

Parameters:

pathMap - the PathMap to which the expression should be added

pathMapNodeSet - the PathMapNodeSet to which the paths embodied in this expression should be added

Returns:

the pathMapNodeSet representing the points in the source document that are both reachable by this expression, and that represent possible results of this expression. For an expression that does navigation, it represents the end of the arc in the path map that describes the navigation route. For other expressions, it is the same as the input pathMapNode.

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 Expression

Parameters:

out - output destination

explainStreaming

protected void explainStreaming(ExpressionPresenter out)

getExpressionCompiler

public ExpressionCompiler getExpressionCompiler()

Return the compiler of the ApplyTemplates expression

Overrides:

getExpressionCompiler in class Expression

Returns:

the relevant ExpressionCompiler

getStreamingAdjunct

public ApplyTemplatesAdjunct getStreamingAdjunct()

Description copied from class: Expression

Get a class that supports streamed evaluation of this expression

Overrides:

getStreamingAdjunct in class Expression

Returns:

the relevant StreamingAdjunct, or null if none is available