net.sf.saxon.expr
Class ForExpression

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

All Implemented Interfaces:

Binding, Expression, Instr, Locatable, java.io.Serializable

public class ForExpression

extends Assignation

implements Instr

A ForExpression maps an expression over a sequence. This version works with range variables, it doesn't change the context information

See Also:

Serialized Form

Field Summary

 

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

action, declaration, sequence, slotNumber, variableName

 

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

lineNumber, NO_ARGUMENTS, staticProperties

 

Constructor Summary

ForExpression()

 

Method Summary
Expression	analyze(StaticContext env)           Type-check the expression
int	computeCardinality()           Determine the static cardinality of the expression
void	display(int level, NamePool pool)           Diagnostic print of expression structure
ItemType	getItemType()           Determine the data type of the items returned by the expression, if possible
SequenceIterator	iterate(XPathContext context)           Iterate over the sequence of values
void	process(XPathContext context)           Process this expression as an instruction, writing results to the current outputter
TailCall	processLeavingTail(XPathContext context)           Process the instruction, optionally returning an uncompleted tail call to be invoked by the caller
void	setAction(Expression action)           Add the "return" or "satisfies" expression, and fix up all references to the range variable that occur within that expression
void	setPositionVariable(RangeVariableDeclaration decl)           Set the reference to the position variable (XQuery only)

 

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

evaluateVariable, getRequiredType, getSubExpressions, getVariableName, promote, setSequence, setSlotNumber, setVariableDeclaration, simplify

 

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

computeDependencies, computeSpecialProperties, computeStaticProperties, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, getCardinality, getDependencies, getIntrinsicDependencies, getLineNumber, getSourceLocator, getSpecialProperties, markTailFunctionCalls, setLineNumber, typeError

 

Methods inherited from class java.lang.Object

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

 

Methods inherited from interface net.sf.saxon.instruct.Locatable

getSourceLocator

 

Constructor Detail

ForExpression

public ForExpression()

setPositionVariable

public void setPositionVariable(RangeVariableDeclaration decl)

Set the reference to the position variable (XQuery only)

setAction

public void setAction(Expression action)

Description copied from class: Assignation

Add the "return" or "satisfies" expression, and fix up all references to the range variable that occur within that expression

Overrides:

setAction in class Assignation

Parameters:

action - the expression that occurs after the "return" keyword of a "for" expression, the "satisfies" keyword of "some/every", or the ":=" operator of a "let" expression.

This method must be called after calling setVariableDeclaration()

analyze

public Expression analyze(StaticContext env)
                   throws XPathException

Type-check the expression

Specified by:

analyze in interface 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

iterate

public SequenceIterator iterate(XPathContext context)
                         throws XPathException

Iterate over the sequence of values

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

process

public void process(XPathContext context)
             throws javax.xml.transform.TransformerException

Process this expression as an instruction, writing results to the current outputter

Specified by:

process in interface Instr

Parameters:

context - The dynamic context, giving access to the current node, the current variables, etc.

javax.xml.transform.TransformerException

processLeavingTail

public TailCall processLeavingTail(XPathContext context)
                            throws javax.xml.transform.TransformerException

Process the instruction, optionally returning an uncompleted tail call to be invoked by the caller

Specified by:

processLeavingTail in interface Instr

Parameters:

context - The dynamic context, giving access to the current node, the current variables, etc.

javax.xml.transform.TransformerException

getItemType

public ItemType getItemType()

Determine the data type of the items returned by the expression, if possible

Specified by:

getItemType in interface Expression

Returns:

one of the values Type.STRING, Type.BOOLEAN, Type.NUMBER, Type.NODE, or Type.ITEM (meaning not known in advance)

computeCardinality

public int computeCardinality()

Determine the static cardinality of the expression

Specified by:

computeCardinality in class ComputedExpression

display

public void display(int level,
                    NamePool pool)

Diagnostic print of expression structure

Specified by:

display in interface Expression

Parameters:

level - indentation level for this expression