public class SubscriptExpression extends SingleItemFilter
EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, PROCESS_METHOD, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, UPDATE_METHOD, WATCH_METHOD
Constructor and Description |
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SubscriptExpression(Expression base,
Expression subscript)
Construct a SubscriptExpression
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Modifier and Type | Method and Description |
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int |
computeCardinality()
Get the static cardinality: this implementation is appropriate for [1] and [last()] which will always
return something if the input is non-empty
|
int |
computeHashCode()
get HashCode for comparing two expressions.
|
Expression |
copy(RebindingMap rebindings)
Copy an expression.
|
boolean |
equals(java.lang.Object other)
Compare two expressions to see if they are equal
|
Item |
evaluateItem(XPathContext context)
Evaluate an expression as a single item.
|
void |
export(ExpressionPresenter destination)
Diagnostic print of expression structure.
|
java.lang.String |
getExpressionName()
Get a name identifying the kind of expression, in terms meaningful to a user.
|
int |
getImplementationMethod()
An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process().
|
java.lang.String |
getStreamerName()
Get the (partial) name of a class that supports streaming of this kind of expression
|
Expression |
getSubscript() |
Expression |
getSubscriptExpression()
Get the subscript expression
|
java.lang.Iterable<Operand> |
operands()
Get the immediate sub-expressions of this expression, with information about the relationship
of each expression to its parent expression.
|
Expression |
optimize(ExpressionVisitor visitor,
ContextItemStaticInfo contextInfo)
Perform optimisation of an expression and its subexpressions.
|
void |
setSubscript(Expression subscript) |
java.lang.String |
toShortString()
The toString() method for an expression attempts to give a representation of the expression
in an XPath-like form.
|
java.lang.String |
toString()
The toString() method for an expression attempts to give a representation of the expression
in an XPath-like form.
|
Expression |
typeCheck(ExpressionVisitor visitor,
ContextItemStaticInfo contextInfo)
Type-check the expression.
|
getOperandRole
computeSpecialProperties, displayOperator, getBaseExpression, getItemType, getOperand, setBaseExpression
addToPathMap, adoptChildExpression, allowExtractingCommonSubexpressions, checkedOperands, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, dynamicError, effectiveBooleanValue, evaluateAsString, evaluatePendingUpdates, explain, getCardinality, getConfiguration, getConstructType, getCost, getDependencies, getEvaluationMethod, getExtraProperty, getIntegerBounds, getInterpretedExpression, getIntrinsicDependencies, getLocalRetainedStaticContext, getLocation, getNetCost, getObjectName, getPackageData, getParentExpression, getProperties, getProperty, getRetainedStaticContext, getScopingExpression, getSlotsUsed, getSpecialProperties, getStaticBaseURI, getStaticBaseURIString, getStaticType, getStaticUType, hasCompatibleStaticContext, hashCode, hasVariableBinding, identityHashCode, implementsStaticTypeCheck, isCallOn, isCallOnSystemFunction, isIdentical, isInstruction, isLiftable, isMultiThreaded, isSameExpression, isStaticPropertiesKnown, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterate, markTailFunctionCalls, operandList, operandSparseList, optimizeChildren, process, resetLocalStaticProperties, restoreParentPointers, setEvaluationMethod, setExtraProperty, setFiltered, setFlattened, setLocation, setParentExpression, setRetainedStaticContext, setRetainedStaticContextLocally, setRetainedStaticContextThoroughly, setStaticProperty, simplify, simplifyChildren, staticTypeCheck, suppressValidation, toPattern, typeCheckChildren, typeError, unordered, verifyParentPointers, verifyParentPointers
public SubscriptExpression(Expression base, Expression subscript)
base
- the expression to be filteredsubscript
- the positional subscript filterpublic Expression getSubscript()
public void setSubscript(Expression subscript)
public Expression typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) throws XPathException
typeCheck
in class UnaryExpression
visitor
- an expression visitorcontextInfo
- Information available statically about the context item: whether it is (possibly)
absent; its static type; its streaming posture.XPathException
- if an error is discovered during this phase
(typically a type error)public Expression optimize(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) throws XPathException
SingleItemFilter
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.
optimize
in class SingleItemFilter
visitor
- an expresion visitorcontextInfo
- 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
XPathException
- if an error is discovered during this phase
(typically a type error)public Expression copy(RebindingMap rebindings)
copy
in class Expression
rebindings
- public java.lang.Iterable<Operand> operands()
Expression
If the expression is a Callable, then it is required that the order of the operands returned by this function is the same as the order of arguments supplied to the corresponding call() method.
operands
in class UnaryExpression
public Expression getSubscriptExpression()
public int getImplementationMethod()
getImplementationMethod
in class Expression
Expression.ITERATE_METHOD
or Expression.EVALUATE_METHOD
or
Expression.PROCESS_METHOD
public boolean equals(java.lang.Object other)
equals
in class UnaryExpression
other
- the other expressionpublic int computeHashCode()
UnaryExpression
computeHashCode
in class UnaryExpression
public int computeCardinality()
computeCardinality
in class SingleItemFilter
StaticProperty.ALLOWS_ZERO_OR_ONE
,
StaticProperty.EXACTLY_ONE
, StaticProperty.ALLOWS_ONE_OR_MORE
,
StaticProperty.ALLOWS_ZERO_OR_MORE
public java.lang.String getStreamerName()
getStreamerName
in class Expression
public Item evaluateItem(XPathContext context) throws XPathException
Expression
evaluateItem
in class Expression
context
- The context in which the expression is to be evaluatedXPathException
- if any dynamic error occurs evaluating the
expressionpublic java.lang.String getExpressionName()
getExpressionName
in class Expression
public void export(ExpressionPresenter destination) throws XPathException
export
in interface ExportAgent
export
in class UnaryExpression
destination
- the expression presenter used to display the structureXPathException
- if the export fails, for example if an expression is found that won't work
in the target environment.public java.lang.String toString()
The toString() method for an expression attempts to give a representation of the expression in an XPath-like form.
For subclasses of Expression that represent XPath expressions, the result should always be a string that parses as an XPath 3.0 expression.
toString
in class UnaryExpression
public java.lang.String toShortString()
The toString() method for an expression attempts to give a representation of the expression in an XPath-like form.
For subclasses of Expression that represent XPath expressions, the result should always be a string that parses as an XPath 3.0 expression.
toShortString
in class UnaryExpression
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