net.sf.saxon.expr
Class QuantifiedExpression

java.lang.Object
  net.sf.saxon.expr.Expression
      net.sf.saxon.expr.Assignation
          net.sf.saxon.expr.QuantifiedExpression

All Implemented Interfaces:

Serializable, SourceLocator, LocationProvider, SaxonLocator, Binding, EvaluableItem, SequenceIterable, InstructionInfo, Locator

public class QuantifiedExpression
extends Assignation

A QuantifiedExpression tests whether some/all items in a sequence satisfy some condition.

See Also:

Serialized Form

Field Summary

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

action, requiredType, sequence, slotNumber, variableName

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

EVALUATE_METHOD, EVENT_FEED_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, locationId, PROCESS_METHOD, PUSH_SELECTION, staticProperties, WATCH_METHOD

Constructor Summary

QuantifiedExpression()

Method Summary

void	checkForUpdatingSubexpressions() Check to ensure that this expression does not contain any updating subexpressions.
int	computeCardinality() Determine the static cardinality
int	computeSpecialProperties() Determine the special properties of this expression
Expression	copy() Copy an expression.
boolean	effectiveBooleanValue(XPathContext context) Get the result as a boolean
Item	evaluateItem(XPathContext context) Evaluate the expression to return a singleton value
void	explain(ExpressionPresenter out) Diagnostic print of expression structure.
String	getExpressionName() Get a name identifying the kind of expression, in terms meaningful to a user.
ItemType	getItemType(TypeHierarchy th) Determine the data type of the items returned by the expression
int	getOperator() Get the operator, either Token.SOME or Token.EVERY
boolean	hasLoopingSubexpression(Expression child) Given an expression that is an immediate child of this expression, test whether the evaluation of the parent expression causes the child expression to be evaluated repeatedly
boolean	isUpdatingExpression() Determine whether this is an updating expression as defined in the XQuery update specification
Expression	optimize(ExpressionVisitor visitor, ItemType contextItemType) Perform optimisation of an expression and its subexpressions.
void	setOperator(int operator) Set the operator, either Token.SOME or Token.EVERY
String	toString() The toString() method for an expression attempts to give a representation of the expression in an XPath-like form, but there is no guarantee that the syntax will actually be true XPath.
Expression	typeCheck(ExpressionVisitor visitor, ItemType contextItemType) Type-check the expression

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

addReference, addToPathMap, evaluateVariable, extendBindingList, getAction, getLocalSlotNumber, getNominalReferenceCount, getObjectName, getRequiredSlots, getRequiredType, getSequence, getVariableName, getVariableQName, isAssignable, isGlobal, isIndexedVariable, iterateSubExpressions, promote, promoteWhereClause, refineTypeInformation, replaceSubExpression, replaceVariable, setAction, setIndexedVariable, setRequiredType, setSequence, setSlotNumber, setVariableQName, simplify, suppressValidation

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

adoptChildExpression, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, dynamicError, evaluateAsString, evaluatePendingUpdates, explain, getCardinality, getColumnNumber, getColumnNumber, getConstructType, getContainer, getDependencies, getEvaluationMethod, getExecutable, getHostLanguage, getImplementationMethod, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, implementsStaticTypeCheck, isSubtreeExpression, isVacuousExpression, iterate, iterateEvents, iterateSameFocusSubExpressions, markTailFunctionCalls, process, resetLocalStaticProperties, setContainer, setEvaluationMethod, setFiltered, setFlattened, setLocationId, staticTypeCheck, typeError

Methods inherited from class java.lang.Object

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

Constructor Detail

QuantifiedExpression

public QuantifiedExpression()

Method Detail

getExpressionName

public String getExpressionName()

Get a name identifying the kind of expression, in terms meaningful to a user.

Overrides:

getExpressionName in class Expression

Returns:

a name identifying the kind of expression, in terms meaningful to a user. The name will always be in the form of a lexical XML QName, and should match the name used in explain() output displaying the expression.

setOperator

public void setOperator(int operator)

Set the operator, either Token.SOME or Token.EVERY

Parameters:

operator - the operator

getOperator

public int getOperator()

Get the operator, either Token.SOME or Token.EVERY

Returns:

the operator

computeCardinality

public int computeCardinality()

Determine the static cardinality

Specified by:

computeCardinality in class Expression

Returns:

the computed cardinality, as one of the values StaticProperty.ALLOWS_ZERO_OR_ONE, StaticProperty.EXACTLY_ONE, StaticProperty.ALLOWS_ONE_OR_MORE, StaticProperty.ALLOWS_ZERO_OR_MORE

typeCheck

public Expression typeCheck(ExpressionVisitor visitor,
                            ItemType contextItemType)
                     throws XPathException

Type-check the expression

Overrides:

typeCheck in class Expression

Parameters:

visitor - an expression visitor

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 Type.ITEM_TYPE

Returns:

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

Throws:

XPathException - if an error is discovered during this phase (typically a type error)

optimize

public Expression optimize(ExpressionVisitor visitor,
                           ItemType contextItemType)
                    throws XPathException

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.

Overrides:

optimize in class Expression

Parameters:

visitor - an expression visitor

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 Type.ITEM_TYPE

Returns:

the original expression, rewritten if appropriate to optimize execution

Throws:

XPathException - if an error is discovered during this phase (typically a type error)

checkForUpdatingSubexpressions

public void checkForUpdatingSubexpressions()
                                    throws XPathException

Check to ensure that this expression does not contain any updating subexpressions. This check is overridden for those expressions that permit updating subexpressions.

Overrides:

checkForUpdatingSubexpressions in class Assignation

Throws:

XPathException - if the expression has a non-permitted updateing subexpression

isUpdatingExpression

public boolean isUpdatingExpression()

Determine whether this is an updating expression as defined in the XQuery update specification

Overrides:

isUpdatingExpression in class Assignation

Returns:

true if this is an updating expression

copy

public Expression copy()

Copy an expression. This makes a deep copy.

Specified by:

copy in class Expression

Returns:

the copy of the original expression

hasLoopingSubexpression

public boolean hasLoopingSubexpression(Expression child)

Given an expression that is an immediate child of this expression, test whether the evaluation of the parent expression causes the child expression to be evaluated repeatedly

Overrides:

hasLoopingSubexpression in class Expression

Parameters:

child - the immediate subexpression

Returns:

true if the child expression is evaluated repeatedly

computeSpecialProperties

public int computeSpecialProperties()

Determine the special properties of this expression

Overrides:

computeSpecialProperties in class Expression

Returns:

StaticProperty.NON_CREATIVE.

evaluateItem

public Item evaluateItem(XPathContext context)
                  throws XPathException

Evaluate the expression to return a singleton value

Specified by:

evaluateItem in interface EvaluableItem

Overrides:

evaluateItem in class Expression

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

effectiveBooleanValue

public boolean effectiveBooleanValue(XPathContext context)
                              throws XPathException

Get the result as a boolean

Overrides:

effectiveBooleanValue in class Expression

Parameters:

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

Returns:

the effective boolean value

Throws:

XPathException - if any dynamic error occurs evaluating the expression

getItemType

public ItemType getItemType(TypeHierarchy th)

Determine the data type of the items returned by the expression

Specified by:

getItemType in class Expression

Parameters:

th - the type hierarchy cache

Returns:

Type.BOOLEAN

toString

public String toString()

The toString() method for an expression attempts to give a representation of the expression in an XPath-like form, but there is no guarantee that the syntax will actually be true XPath. In the case of XSLT instructions, the toString() method gives an abstracted view of the syntax

Overrides:

toString in class Expression

Returns:

a representation of the expression as a string

explain

public void explain(ExpressionPresenter out)

Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.

Specified by:

explain in class Expression

Parameters:

out - the expression presenter used to display the structure