net.sf.saxon.instruct

Class SimpleNodeConstructor

public abstract class SimpleNodeConstructor extends Instruction

Common superclass for XSLT instructions whose content template produces a text value: xsl:attribute, xsl:comment, xsl:processing-instruction, xsl:namespace, and xsl:text

Field Summary
protected Expression	select

Constructor Summary
	SimpleNodeConstructor()

Method Summary
protected String	checkContent(String data, XPathContext context) Check the content of the node, and adjust it if necessary.
int	computeSpecialProperties() Get the static properties of this expression (other than its type).
boolean	createsNewNodes() Determine whether this instruction creates new nodes.
void	display(int level, NamePool pool, PrintStream out) Display this instruction as an expression, for diagnostics
Item	evaluateItem(XPathContext context) Evaluate as an expression.
protected int	evaluateNameCode(XPathContext context)
CharSequence	expandChildren(XPathContext context) Expand the stylesheet elements subordinate to this one, returning the result as a string.
Expression	getSelect()
SequenceIterator	iterate(XPathContext context)
Iterator	iterateSubExpressions()
abstract void	localTypeCheck(StaticContext env, ItemType contextItemType)
Expression	optimize(Optimizer opt, StaticContext env, ItemType contextItemType)
protected void	promoteInst(PromotionOffer offer) Offer promotion for subexpressions.
void	setSelect(Expression select, Configuration config)
Expression	simplify(StaticContext env)
Expression	typeCheck(StaticContext env, ItemType contextItemType) The typeCheck() method is called in XQuery, where node constructors are implemented as Expressions.

Method Detail

checkContent

protected String checkContent(String data, XPathContext context)

Check the content of the node, and adjust it if necessary. The checks depend on the node kind.

Parameters: data the supplied content context the dynamic context

Returns: the original content, unless adjustments are needed

Throws: DynamicError if the content is invalid

Get the static properties of this expression (other than its type). The result is bit-signficant. These properties are used for optimizations. In general, if property bit is set, it is true, but if it is unset, the value is unknown.

Returns: a set of flags indicating static properties of this expression

createsNewNodes

public final boolean createsNewNodes()

Determine whether this instruction creates new nodes. This implementation returns true.

display

public void display(int level, NamePool pool, PrintStream out)

Display this instruction as an expression, for diagnostics

evaluateItem

public Item evaluateItem(XPathContext context)

Evaluate as an expression. We rely on the fact that when these instructions are generated by XQuery, there will always be a valueExpression to evaluate the content

evaluateNameCode

protected int evaluateNameCode(XPathContext context)

expandChildren

public CharSequence expandChildren(XPathContext context)

Expand the stylesheet elements subordinate to this one, returning the result as a string. The expansion must not generate any element or attribute nodes.

Parameters: context The dynamic context for the transformation

getSelect

public Expression getSelect()

iterate

public SequenceIterator iterate(XPathContext context)

iterateSubExpressions

public Iterator iterateSubExpressions()

localTypeCheck

public abstract void localTypeCheck(StaticContext env, ItemType contextItemType)

optimize

public Expression optimize(Optimizer opt, StaticContext env, ItemType contextItemType)

promoteInst

protected void promoteInst(PromotionOffer offer)

Offer promotion for subexpressions. The offer will be accepted if the subexpression is not dependent on the factors (e.g. the context item) identified in the PromotionOffer. By default the offer is not accepted - this is appropriate in the case of simple expressions such as constant values and variable references where promotion would give no performance advantage. This method is always called at compile time.

Parameters: offer details of the offer, for example the offer to move expressions that don't depend on the context to an outer level in the containing expression

Throws: XPathException if any error is detected

Parameters: env The static context for the query

Returns: the rewritten expression

Throws: XPathException if any static errors are found in this expression or any of its children

Class SimpleNodeConstructor

Field Detail

select

Constructor Detail

SimpleNodeConstructor