net.sf.saxon.instruct
Class UseAttributeSets

java.lang.Object
  net.sf.saxon.expr.Expression
      net.sf.saxon.instruct.Instruction
          net.sf.saxon.instruct.UseAttributeSets

All Implemented Interfaces:

Serializable, SourceLocator, Container, EvaluableItem, SequenceIterable, TailCallReturner, InstructionInfoProvider

public class UseAttributeSets
extends Instruction

This instruction corresponds to a use-attribute-sets attribute on a literal result element, xsl:element, or xsl:copy.

See Also:

Serialized Form

Field Summary

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

EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD

Constructor Summary

UseAttributeSets(AttributeSet[] sets)

Method Summary

void	display(int level, PrintStream out, Configuration config) Diagnostic print of expression structure.
ItemType	getItemType(TypeHierarchy th) Get the item type of the items returned by evaluating this instruction
Expression	optimize(Optimizer opt, StaticContext env, ItemType contextItemType) Perform optimisation of an expression and its subexpressions.
TailCall	processLeavingTail(XPathContext context) ProcessLeavingTail: called to do the real work of this instruction.
Expression	simplify(StaticContext env) Simplify an expression.
Expression	typeCheck(StaticContext env, ItemType contextItemType) Perform type checking of an expression and its subexpressions.

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

appendItem, computeCardinality, computeSpecialProperties, createsNewNodes, evaluateAsString, evaluateItem, getImplementationMethod, getInstructionInfo, getInstructionNameCode, getSourceLocator, isXSLT, iterate, process, promote

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

adoptChildExpression, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, effectiveBooleanValue, getCardinality, getColumnNumber, getContainingProcedure, getDependencies, getExecutable, getHostLanguage, getIntrinsicDependencies, getLineNumber, getLocationId, getLocationProvider, getParentExpression, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasBadParentPointer, iterateSubExpressions, markTailFunctionCalls, replaceSubExpression, resetStaticProperties, setLocationId, setParentExpression, setParentExpression, suppressValidation

Methods inherited from class java.lang.Object

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

Methods inherited from interface javax.xml.transform.SourceLocator

getColumnNumber, getLineNumber, getPublicId, getSystemId

Constructor Detail

UseAttributeSets

public UseAttributeSets(AttributeSet[] sets)

Method Detail

simplify

public Expression simplify(StaticContext env)
                    throws XPathException

Simplify an expression. This performs any static optimization (by rewriting the expression as a different expression). The default implementation does nothing.

Specified by:

simplify in class Instruction

Returns:

the simplified expression

Throws:

XPathException - if an error is discovered during expression rewriting

optimize

public Expression optimize(Optimizer opt,
                           StaticContext env,
                           ItemType 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:

opt - the optimizer in use. This provides access to supporting functions; it also allows different optimization strategies to be used in different circumstances.

env - the static context of the expression

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:

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

XPathException

typeCheck

public Expression typeCheck(StaticContext env,
                            ItemType contextItemType)
                     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:

env - the static context of the expression

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 to perform necessary run-time type checks, and to perform other type-related optimizations

Throws:

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

XPathException

getItemType

public ItemType getItemType(TypeHierarchy th)

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

Overrides:

getItemType in class Instruction

Parameters:

th -

Returns:

the static item type of the instruction

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

display

public void display(int level,
                    PrintStream out,
                    Configuration config)

Diagnostic print of expression structure. The expression is written to the System.err output stream

Specified by:

display in class Expression

Parameters:

level - indentation level for this expression

out - Output destination

config -