net.sf.saxon.expr

Class ContextItemExpression

public final class ContextItemExpression extends ComputedExpression

This class represents the expression "(dot)", which always returns the context item. This may be a AtomicValue or a Node.
Field Summary
ItemTypeitemType
Constructor Summary
ContextItemExpression()
Method Summary
intcomputeCardinality()
Get the static cardinality
intcomputeSpecialProperties()
Determine the special properties of this expression
voiddisplay(int level, NamePool pool, PrintStream out)
Diagnostic print of expression structure
booleanequals(Object other)
Is this expression the same as another expression?
ItemevaluateItem(XPathContext context)
Evaluate the expression
intgetIntrinsicDependencies()
ItemTypegetItemType(TypeHierarchy th)
Determine the item type
inthashCode()
get HashCode for comparing two expressions
SequenceIteratoriterate(XPathContext context)
Iterate over the value of the expression
Expressionoptimize(Optimizer opt, StaticContext env, ItemType contextItemType)
Perform optimisation of an expression and its subexpressions.
ExpressiontypeCheck(StaticContext env, ItemType contextItemType)
Type-check the expression.

Field Detail

itemType

ItemType itemType

Constructor Detail

ContextItemExpression

public ContextItemExpression()

Method Detail

computeCardinality

public int computeCardinality()
Get the static cardinality

computeSpecialProperties

public int computeSpecialProperties()
Determine the special properties of this expression

Returns: NON_CREATIVE

display

public void display(int level, NamePool pool, PrintStream out)
Diagnostic print of expression structure

equals

public boolean equals(Object other)
Is this expression the same as another expression?

evaluateItem

public Item evaluateItem(XPathContext context)
Evaluate the expression

getIntrinsicDependencies

public int getIntrinsicDependencies()

getItemType

public ItemType getItemType(TypeHierarchy th)
Determine the item type

Parameters: th

hashCode

public int hashCode()
get HashCode for comparing two expressions

iterate

public SequenceIterator iterate(XPathContext context)
Iterate over the value of the expression

optimize

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

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 ITEM_TYPE

Returns: the original expression, rewritten if appropriate to optimize execution

Throws: net.sf.saxon.trans.StaticError if an error is discovered during this phase (typically a type error)

typeCheck

public Expression typeCheck(StaticContext env, ItemType contextItemType)
Type-check the expression.