org.exist.xquery
Class ForExpr

java.lang.Object
  org.exist.xquery.AbstractExpression
      org.exist.xquery.BindingExpression
          org.exist.xquery.ForExpr

All Implemented Interfaces:

Expression

public class ForExpr
extends BindingExpression

Represents an XQuery "for" expression.

Author:

Wolfgang Meier

Field Summary

Fields inherited from interface org.exist.xquery.Expression

DOT_TEST, EXPRESSION_ID_INVALID, IGNORE_CONTEXT, IN_PREDICATE, IN_UPDATE, IN_WHERE_CLAUSE, NEED_INDEX_INFO, NO_CONTEXT_ID, SINGLE_STEP_EXECUTION

Constructor Summary

ForExpr(XQueryContext context)

Method Summary

void	accept(ExpressionVisitor visitor) Start traversing the expression tree using the specified ExpressionVisitor.
void	analyze(AnalyzeContextInfo contextInfo, OrderSpec[] orderBy)
void	analyze(AnalyzeContextInfo contextInfo, OrderSpec[] orderBy, GroupSpec[] groupBy)
void	dump(ExpressionDumper dumper) Write a diagnostic dump of the expression to the passed ExpressionDumper.
Sequence	eval(Sequence contextSequence, Item contextItem, Sequence resultSequence, GroupedValueSequenceTable groupedSequence) This implementation tries to process the "where" clause in advance, i.e.
void	resetState() Called to inform an expression that it should reset to its initial state.
int	returnsType() The static return type of the expression.
void	setPositionalVariable(String var) A "for" expression may have an optional positional variable whose QName can be set via this method.
String	toString()

Methods inherited from class org.exist.xquery.BindingExpression

analyze, eval, getInputSequence, getReturnExpression, getVariable, getWhereExpression, preselect, setGroupReturnExpr, setGroupSpecs, setGroupVariable, setInputSequence, setOrderSpecs, setReturnExpression, setSequenceType, setToGroupVariable, setVariable, setWhereExpression

Methods inherited from class org.exist.xquery.AbstractExpression

eval, getASTNode, getCardinality, getContextDocSet, getContextId, getDependencies, getExpressionId, setASTNode, setContextDocSet, setPrimaryAxis

Methods inherited from class java.lang.Object

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

Constructor Detail

ForExpr

public ForExpr(XQueryContext context)

Method Detail

setPositionalVariable

public void setPositionalVariable(String var)

A "for" expression may have an optional positional variable whose QName can be set via this method.

Parameters:

var -

analyze

public void analyze(AnalyzeContextInfo contextInfo,
                    OrderSpec[] orderBy)
             throws XPathException

Throws:

XPathException

analyze

public void analyze(AnalyzeContextInfo contextInfo,
                    OrderSpec[] orderBy,
                    GroupSpec[] groupBy)
             throws XPathException

Specified by:

analyze in class BindingExpression

Throws:

XPathException

eval

public Sequence eval(Sequence contextSequence,
                     Item contextItem,
                     Sequence resultSequence,
                     GroupedValueSequenceTable groupedSequence)
              throws XPathException

This implementation tries to process the "where" clause in advance, i.e. in one single step. This is possible if the input sequence is a node set and the where expression has no dependencies on other variables than those declared in this "for" statement.

Specified by:

eval in class BindingExpression

Throws:

XPathException

See Also:

Expression.eval(Sequence, Item)

dump

public void dump(ExpressionDumper dumper)

Description copied from interface: Expression

Write a diagnostic dump of the expression to the passed ExpressionDumper.

Parameters:

dumper - the expression dumper to write to

toString

public String toString()

Overrides:

toString in class Object

returnsType

public int returnsType()

Description copied from interface: Expression

The static return type of the expression. This method should return one of the type constants defined in class Type. If the return type cannot be determined statically, return Type.ITEM.

Specified by:

returnsType in interface Expression

Overrides:

returnsType in class BindingExpression

resetState

public void resetState()

Description copied from interface: Expression

Called to inform an expression that it should reset to its initial state. All cached data in the expression object should be dropped. For example, the document() function calls this method whenever the input document set has changed.

Specified by:

resetState in interface Expression

Overrides:

resetState in class BindingExpression

accept

public void accept(ExpressionVisitor visitor)

Description copied from interface: Expression

Start traversing the expression tree using the specified ExpressionVisitor.

Specified by:

accept in interface Expression

Overrides:

accept in class AbstractExpression