Package com.saxonica.expr

Class ObjectLookupExpression

java.lang.Object

net.sf.saxon.expr.Expression

net.sf.saxon.expr.BinaryExpression

net.sf.saxon.expr.LookupExpression

com.saxonica.expr.ObjectLookupExpression

All Implemented Interfaces:

ExportAgent, Locatable, IdentityComparable, Traceable

public class ObjectLookupExpression
extends LookupExpression

Saxon extension: a lookup expression of the form X?Y where X is a Java external object and Y is a method defined on that object. This class is used only where it is statically known that X is a Java external object, in which case it is often possible to determine the Java method to be called statically.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	ObjectLookupExpression.ObjectLookupElaborator

Nested classes/interfaces inherited from class net.sf.saxon.expr.LookupExpression

LookupExpression.LookupElaborator

Field Summary

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

isArrayLookup, isMapLookup, isSingleContainer, isSingleEntry

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

operator

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

EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, MAX_COST, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, PROCESS_METHOD, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, UPDATE_METHOD, WATCH_METHOD

Constructor Summary

Constructors

Constructor	Description
ObjectLookupExpression(Expression start, Expression step)

Method Summary

Modifier and Type	Method	Description
protected int	computeCardinality()	Determine the static cardinality of the expression
LookupExpression	copy(RebindingMap rebindings)	Copy an expression.
ItemType	getItemType()	Determine the data type of the items returned by this expression
SequenceIterator	iterate(XPathContext context)	Iterate the lookup-expression in a given context
Expression	typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo)	Type-check the expression

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

computeHashCode, equals, export, getCost, getElaborator, getExpressionName, getImplementationMethod, getOperandRole, getStaticUType, mustBeArrayOrMap, optimize, toString

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

computeSpecialProperties, displayOperator, explainExtraAttributes, getLhs, getLhsExpression, getOperator, getRhs, getRhsExpression, isAssociative, isCommutative, isInverse, operands, setFlattened, setLhsExpression, setRhsExpression, tag, toShortString

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

addToPathMap, adoptChildExpression, allowExtractingCommonSubexpressions, checkedOperands, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, dispatchTailCall, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, explain, getCardinality, getConfiguration, getDependencies, getEvaluationMethod, getExtraProperty, getIntegerBounds, getIntrinsicDependencies, getLocalRetainedStaticContext, getLocation, getNetCost, getObjectName, getPackageData, getParentExpression, getProperties, getProperty, getRetainedStaticContext, getScopingExpression, getSlotsUsed, getSpecialProperties, getStaticBaseURI, getStaticBaseURIString, getStaticType, getStreamerName, getTracingTag, hasCompatibleStaticContext, hashCode, hasSpecialProperty, hasVariableBinding, identityHashCode, implementsStaticTypeCheck, isCallOn, isEqual, isIdentical, isInstruction, isLiftable, isMultiThreaded, isStaticPropertiesKnown, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, makeElaborator, markTailFunctionCalls, operandList, operandSparseList, optimizeChildren, prepareForStreaming, process, resetLocalStaticProperties, restoreParentPointers, setEvaluationMethod, setExtraProperty, setFiltered, setLocation, setParentExpression, setRetainedStaticContext, setRetainedStaticContextLocally, setRetainedStaticContextThoroughly, setStaticProperty, simplify, simplifyChildren, staticTypeCheck, supportsLazyEvaluation, suppressValidation, toPattern, typeCheckChildren, typeError, unordered, verifyParentPointers, withLocation

Methods inherited from class java.lang.Object

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

Methods inherited from interface net.sf.saxon.trace.Traceable

gatherProperties

Constructor Detail

ObjectLookupExpression

public ObjectLookupExpression(Expression start,
                              Expression step)

Method Detail

getItemType

public final ItemType getItemType()

Description copied from class: LookupExpression

Determine the data type of the items returned by this expression

Overrides:

getItemType in class LookupExpression

Returns:

the type of the expression, as far as this is known. Prior to type-checking, the method returns AnyItemType

typeCheck

public Expression typeCheck(ExpressionVisitor visitor,
                            ContextItemStaticInfo contextInfo)
                     throws XPathException

Description copied from class: LookupExpression

Type-check the expression

Overrides:

typeCheck in class LookupExpression

Parameters:

visitor - an expression visitor

contextInfo - Information available statically about the context item: whether it is (possibly) absent; its static type; its streaming posture.

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)

copy

public LookupExpression copy(RebindingMap rebindings)

Copy an expression. This makes a deep copy.

Overrides:

copy in class LookupExpression

Parameters:

rebindings - a mutable list of (old binding, new binding) pairs that is used to update the bindings held in any local variable references that are copied.

Returns:

the copy of the original expression

computeCardinality

protected int computeCardinality()

Determine the static cardinality of the expression

Overrides:

computeCardinality in class LookupExpression

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. May also return StaticProperty.ALLOWS_ZERO if the result is known to be an empty sequence, or StaticProperty.ALLOWS_MANY if if is known to return a sequence of length two or more.

iterate

public SequenceIterator iterate(XPathContext context)
                         throws XPathException

Iterate the lookup-expression in a given context

Overrides:

iterate in class LookupExpression

Parameters:

context - the evaluation context

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