net.sf.saxon.expr
Class ContextItemExpression

java.lang.Object
  |
  +--net.sf.saxon.expr.ComputedExpression
        |
        +--net.sf.saxon.expr.ContextItemExpression

All Implemented Interfaces:

Expression, java.io.Serializable

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.

See Also:

Serialized Form

Field Summary

 

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

lineNumber, NO_ARGUMENTS, staticProperties

 

Constructor Summary

ContextItemExpression()

 

Method Summary
Expression	analyze(StaticContext env)           Type-check the expression.
int	computeCardinality()           Get the static cardinality
void	display(int level, NamePool pool)           Diagnostic print of expression structure
boolean	equals(java.lang.Object other)           Is this expression the same as another expression?
Item	evaluateItem(XPathContext context)           Evaluate the expression
int	getIntrinsicDependencies()           Determine the intrinsic dependencies of an expression, that is, those which are not derived from the dependencies of its subexpressions.
ItemType	getItemType()           Determine the item type
int	hashCode()           get HashCode for comparing two expressions
SequenceIterator	iterate(XPathContext context)           Iterate over the value of the expression

 

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

computeDependencies, computeSpecialProperties, computeStaticProperties, dynamicError, effectiveBooleanValue, evaluateAsString, getCardinality, getDependencies, getLineNumber, getSourceLocator, getSpecialProperties, getSubExpressions, markTailFunctionCalls, promote, setLineNumber, simplify, typeError

 

Methods inherited from class java.lang.Object

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

 

Constructor Detail

ContextItemExpression

public ContextItemExpression()

analyze

public Expression analyze(StaticContext env)
                   throws XPathException

Type-check the expression.

Parameters:

env - the static context of the expression

Returns:

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

XPathException

getItemType

public ItemType getItemType()

Determine the item type

Returns:

a value such as Type.STRING, Type.BOOLEAN, Type.NUMBER, Type.NODE, or Type.ITEM (meaning not known at compile time)

computeCardinality

public int computeCardinality()

Get the static cardinality

Specified by:

computeCardinality in class ComputedExpression

equals

public boolean equals(java.lang.Object other)

Is this expression the same as another expression?

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

get HashCode for comparing two expressions

Overrides:

hashCode in class java.lang.Object

getIntrinsicDependencies

public int getIntrinsicDependencies()

Description copied from class: ComputedExpression

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 ComputedExpression

Returns:

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

iterate

public SequenceIterator iterate(XPathContext context)
                         throws XPathException

Iterate over the value of the expression

Specified by:

iterate in interface Expression

Overrides:

iterate in class ComputedExpression

Parameters:

context - supplies the context for evaluation

Returns:

a SequenceIterator that can be used to iterate over the result of the expression

Throws:

XPathException - if any dynamic error occurs evaluating the expression

evaluateItem

public Item evaluateItem(XPathContext context)
                  throws XPathException

Evaluate the expression

Specified by:

evaluateItem in interface Expression

Overrides:

evaluateItem in class ComputedExpression

Parameters:

context - The context in which the expression is to be evaluated

Returns:

the node or atomic value that results from evaluating the expression; or null to indicate that the result is an empty sequence

Throws:

XPathException - if any dynamic error occurs evaluating the expression

display

public void display(int level,
                    NamePool pool)

Diagnostic print of expression structure

Parameters:

level - indentation level for this expression