net.sf.saxon.expr.instruct

Class UseAttributeSet

java.lang.Object

net.sf.saxon.expr.Expression

net.sf.saxon.expr.instruct.Instruction

net.sf.saxon.expr.instruct.UseAttributeSet

All Implemented Interfaces:

ComponentInvocation, ContextOriginator, ExportAgent, TailCallReturner, Locatable, IdentityComparable

public class UseAttributeSet
extends Instruction
implements ComponentInvocation, ContextOriginator

This instruction corresponds to a single QName appearing within a use-attribute-sets attribute on a literal result element, xsl:element, or xsl:copy instruction. Binding to a specific attribute set component is done in the same way as function calls or call-template, allowing attribute sets defined in one package to be overridden in another.

Field Summary

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

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

Constructor Summary

Constructors

Constructor and Description
UseAttributeSet(StructuredQName name, boolean streamable) Create a use-attribute-set expression

Method Summary

Modifier and Type	Method and Description
int	computeHashCode() Compute a hashcode
Expression	copy(RebindingMap rebindings) Copy an expression.
boolean	equals(java.lang.Object obj) Test whether this UseAttributeSets expression is equal to another
void	export(ExpressionPresenter out) Export of expression structure.
int	getBindingSlot() Get the binding slot to be used.
java.lang.String	getExpressionName() Get a name identifying the kind of expression, in terms meaningful to a user.
Component	getFixedTarget() Get the target component if this is known in advance, that is, if the target component is private or final, or in some other cases such as xsl:original.
int	getIntrinsicDependencies() Determine the intrinsic dependencies of an expression, that is, those which are not derived from the dependencies of its subexpressions.
ItemType	getItemType() Get the item type of the items returned by evaluating this instruction
java.lang.String	getStreamerName() Get the (partial) name of a class that supports streaming of this kind of expression
SymbolicName	getSymbolicName() Get the symbolic name of the component that this invocation references
AttributeSet	getTargetAttributeSet() Get the target attribute set to which this instruction is provisionally bound
StructuredQName	getTargetAttributeSetName() Get the target attribute sets of this instruction.
boolean	isDeclaredStreamable()
boolean	isInstruction() Ask whether this expression is an instruction.
static Expression	makeCompositeExpression(java.util.List<UseAttributeSet> targets) Given a list of UseAttributeSet expressions, combine them into a single expression
static java.util.List<UseAttributeSet>	makeUseAttributeSetInstructions(StructuredQName[] targets, StyleElement instruction) Make an list of expressions whose combined effect is to expand the attribute sets named in an [xsl]use-attribute-sets attribute, for example on a literal result element
static Expression	makeUseAttributeSets(StructuredQName[] targets, StyleElement instruction) Make an expression whose effect is to expand the attribute sets named in an [xsl]use-attribute-sets attribute, for example on a literal result element
java.lang.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.
TailCall	processLeavingTail(XPathContext context) ProcessLeavingTail: called to do the real work of this instruction.
void	setBindingSlot(int slot) Set the binding slot to be used.
void	setTarget(AttributeSet target) Set the attribute set to be used.
Expression	typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) Perform type checking of an expression and its subexpressions.

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

alwaysCreatesNewNodes, assembleParams, assembleTunnelParams, computeCardinality, computeSpecialProperties, dynamicError, evaluateAsString, evaluateItem, getConstructType, getImplementationMethod, getInstructionNameCode, getNetCost, getSourceLocator, isXSLT, iterate, mayCreateNewNodes, process, someOperandCreatesNewNodes

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

addToPathMap, adoptChildExpression, allowExtractingCommonSubexpressions, checkedOperands, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, dynamicError, effectiveBooleanValue, evaluatePendingUpdates, explain, getCardinality, getConfiguration, getCost, getDependencies, getEvaluationMethod, getExtraProperty, getIntegerBounds, getInterpretedExpression, getLocalRetainedStaticContext, getLocation, getObjectName, getPackageData, getParentExpression, getProperties, getProperty, getRetainedStaticContext, getScopingExpression, getSlotsUsed, getSpecialProperties, getStaticBaseURI, getStaticBaseURIString, getStaticType, getStaticUType, hasCompatibleStaticContext, hashCode, hasSpecialProperty, hasVariableBinding, identityHashCode, implementsStaticTypeCheck, isCallOn, isEqual, isIdentical, isLiftable, isMultiThreaded, isStaticPropertiesKnown, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, markTailFunctionCalls, operandList, operandSparseList, optimizeChildren, prepareForStreaming, resetLocalStaticProperties, restoreParentPointers, setEvaluationMethod, setExtraProperty, setFiltered, setFlattened, setLocation, setParentExpression, setRetainedStaticContext, setRetainedStaticContextLocally, setRetainedStaticContextThoroughly, setStaticProperty, simplify, simplifyChildren, staticTypeCheck, suppressValidation, toPattern, toShortString, toString, typeCheckChildren, typeError, unordered, verifyParentPointers

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

UseAttributeSet

public UseAttributeSet(StructuredQName name,
                       boolean streamable)

Create a use-attribute-set expression

Parameters:

name - the name of the target attribute set

Method Detail

isInstruction

public boolean isInstruction()

Description copied from class: Expression

Ask whether this expression is an instruction. In XSLT streamability analysis this is used to distinguish constructs corresponding to XSLT instructions from other constructs, typically XPath expressions (but also things like attribute constructors on a literal result element, references to attribute sets, etc. However, an XPath expression within a text value template in a text node of an XSLT stylesheet is treated as an instruction. In a non-XSLT environment (such as XQuery) this property has no meaning and its setting is undefined.

Overrides:

isInstruction in class Instruction

Returns:

true if this construct originates as an XSLT instruction

makeUseAttributeSets

public static Expression makeUseAttributeSets(StructuredQName[] targets,
                                              StyleElement instruction)
                                       throws XPathException

Make an expression whose effect is to expand the attribute sets named in an [xsl]use-attribute-sets attribute, for example on a literal result element

Parameters:

targets - the QNames contained in the use-attribute-sets attribute

instruction - the instruction on which the use-attribute-sets attribute appears

Returns:

the required expression

Throws:

XPathException - if an error occurs, for example no attribute set found with the required name

makeUseAttributeSetInstructions

public static java.util.List<UseAttributeSet> makeUseAttributeSetInstructions(StructuredQName[] targets,
                                                                              StyleElement instruction)
                                                                       throws XPathException

Make an list of expressions whose combined effect is to expand the attribute sets named in an [xsl]use-attribute-sets attribute, for example on a literal result element

Parameters:

targets - the QNames contained in the use-attribute-sets attribute

instruction - the instruction on which the use-attribute-sets attribute appears

Returns:

the required expression

Throws:

XPathException - if an error occurs, for example no attribute set found with the required name

makeCompositeExpression

public static Expression makeCompositeExpression(java.util.List<UseAttributeSet> targets)

Given a list of UseAttributeSet expressions, combine them into a single expression

Parameters:

targets - the list of expressions

Returns:

the combined expression

isDeclaredStreamable

public boolean isDeclaredStreamable()

setTarget

public void setTarget(AttributeSet target)

Set the attribute set to be used.

Parameters:

target - the attribute set to be used

setBindingSlot

public void setBindingSlot(int slot)

Set the binding slot to be used. This is the offset within the binding vector of the containing component where the actual target component is to be found. The target template is not held directly in the invocation instruction/expression itself because it can be overridden in a using package.

Specified by:

setBindingSlot in interface ComponentInvocation

Parameters:

slot - the offset in the binding vector of the containing package where the target component can be found.

getBindingSlot

public int getBindingSlot()

Get the binding slot to be used. This is the offset within the binding vector of the containing component where the actual target component is to be found.

Specified by:

getBindingSlot in interface ComponentInvocation

Returns:

the offset in the binding vector of the containing package where the target component can be found.

getSymbolicName

public SymbolicName getSymbolicName()

Get the symbolic name of the component that this invocation references

Specified by:

getSymbolicName in interface ComponentInvocation

Returns:

the symbolic name of the target component

getTargetAttributeSet

public AttributeSet getTargetAttributeSet()

Get the target attribute set to which this instruction is provisionally bound

Returns:

the provisional attribute set (which might be overridden in another package)

getFixedTarget

public Component getFixedTarget()

Description copied from interface: ComponentInvocation

Get the target component if this is known in advance, that is, if the target component is private or final, or in some other cases such as xsl:original. Otherwise, return null.

Specified by:

getFixedTarget in interface ComponentInvocation

Returns:

the bound component if the binding has been fixed

operands

public java.lang.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.

Specified by:

operands in class Instruction

Returns:

an iterator containing the sub-expressions of this expression

optimize

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

Perform optimisation of an expression and its subexpressions.

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)

copy

public Expression copy(RebindingMap rebindings)

Copy an expression. This makes a deep copy.

Specified by:

copy in class Expression

Parameters:

rebindings - a mutable list of (old binding, new binding) pairs that is used to update the bindings held in any local variable references that are copied.

Returns:

the copy of the original expression

typeCheck

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

Perform type checking of an expression and its subexpressions.

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.

Overrides:

typeCheck in class Expression

Parameters:

visitor - an expression visitor

contextInfo - information about the static type of the context item

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)

getItemType

public ItemType getItemType()

Get the item type of the items returned by evaluating this instruction

Overrides:

getItemType in class Instruction

Returns:

the static item type of the instruction

getIntrinsicDependencies

public int getIntrinsicDependencies()

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

getTargetAttributeSetName

public StructuredQName getTargetAttributeSetName()

Get the target attribute sets of this instruction. Called from generated bytecode.

Returns:

the target attribute sets, as an array

processLeavingTail

public TailCall processLeavingTail(XPathContext context)
                            throws XPathException

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

getExpressionName

public java.lang.String getExpressionName()

Get a name identifying the kind of expression, in terms meaningful to a user.

Overrides:

getExpressionName in class Instruction

Returns:

a name identifying the kind of expression, in terms meaningful to a user. The name will always be in the form of a lexical XML QName, and should match the name used in explain() output displaying the expression.

export

public void export(ExpressionPresenter out)
            throws XPathException

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

Specified by:

export in interface ExportAgent

Specified by:

export in class Expression

Parameters:

out - the expression presenter used to display the structure

Throws:

XPathException - if the export fails, for example if an expression is found that won't work in the target environment.

equals

public boolean equals(java.lang.Object obj)

Test whether this UseAttributeSets expression is equal to another

Overrides:

equals in class Expression

Parameters:

obj - the other expression

Returns:

true if the other operand is an expression and if it can be determined that the two expressions are equivalent, in the sense that they will always return the same result.

computeHashCode

public int computeHashCode()

Compute a hashcode

Overrides:

computeHashCode in class Expression

Returns:

a computed hash code

getStreamerName

public java.lang.String getStreamerName()

Get the (partial) name of a class that supports streaming of this kind of expression

Overrides:

getStreamerName in class Expression

Returns:

the partial name of a class that can be instantiated to provide streaming support in Saxon-EE, or null if there is no such class