public class TailExpression extends Expression
EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, locationId, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, PROCESS_METHOD, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, WATCH_METHOD
Constructor and Description 

TailExpression(Expression base,
int start)
Construct a TailExpression, representing a filter expression of the form
$base[position() >= $start]

Modifier and Type  Method and Description 

int 
computeCardinality()
Compute the static cardinality of this expression

int 
computeSpecialProperties()
Compute the special properties of this expression.

Expression 
copy()
Copy an expression.

boolean 
equals(Object other)
Compare two expressions to see if they are equal

void 
explain(ExpressionPresenter destination)
Diagnostic print of expression structure.

Expression 
getBaseExpression()
Get the base expression (of which this expression returns the tail part of the value)

ExpressionCompiler 
getExpressionCompiler()
Return the compiler of the TailExpression expression

ItemType 
getItemType()
Determine the data type of the expression, if possible.

int 
getStart()
Get the start offset

StreamingAdjunct 
getStreamingAdjunct()
Get a class that supports streamed evaluation of this expression

int 
hashCode() 
SequenceIterator 
iterate(XPathContext context)
Return an Iterator to iterate over the values of a sequence.

Iterable<Operand> 
operands()
Get the immediate subexpressions of this expression, with information about the relationship
of each expression to its parent expression.

Expression 
optimize(ExpressionVisitor visitor,
ContextItemStaticInfo contextItemType)
Perform optimisation of an expression and its subexpressions.

Expression 
promote(PromotionOffer offer,
Expression parent)
Offer promotion for this subexpression.

boolean 
replaceOperand(Expression original,
Expression replacement)
Replace one subexpression by a replacement subexpression

String 
toShortString()
Produce a short string identifying the expression for use in error messages

String 
toString()
The toString() method for an expression attempts to give a representation of the expression
in an XPathlike form.

Expression 
typeCheck(ExpressionVisitor visitor,
ContextItemStaticInfo contextInfo)
Perform type checking of an expression and its subexpressions.

addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, clearStreamabilityData, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, evaluatePendingUpdates, explain, getCardinality, getColumnNumber, getConfiguration, getConstructType, getContainer, getDependencies, getEvaluationMethod, getExpressionName, getHostLanguage, getImplementationMethod, getIntegerBounds, getIntrinsicDependencies, getLineNumber, getLocationId, getObjectName, getPosture, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getStreamability, getSweep, getSystemId, hasVariableBinding, identityHashCode, implementsStaticTypeCheck, isIdentical, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterateEvents, makeStreamingAdjunct, markTailFunctionCalls, operandList, process, resetLocalStaticProperties, setContainer, setEvaluationMethod, setFiltered, setFlattened, setLocationId, setPostureAndSweep, simplify, staticTypeCheck, suppressValidation, toPattern, toStreamingPattern, typeError, unordered
public TailExpression(Expression base, int start)
base
 the expression to be filteredstart
 the position (1based) of the first item to be includedpublic Expression typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) throws XPathException
Expression
This checks statically that the operands of the expression have the correct type; if necessary it generates code to do runtime type checking or type conversion. A static type error is reported only if execution cannot possibly succeed, that is, if a runtime type error is inevitable. The call may return a modified form of the expression.
This method is called after all references to functions and variables have been resolved to the declaration of the function or variable. However, the types of such functions and variables may not be accurately known if they have not been explicitly declared.
If the implementation returns a value other than "this", then it is required to ensure that the location information in the returned expression have been set up correctly. It should not rely on the caller to do this, although for historical reasons many callers do so.
typeCheck
in class Expression
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 contextItemType) throws XPathException
Expression
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 Expression
visitor
 an expression visitorcontextItemType
 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 promote(PromotionOffer offer, Expression parent) throws XPathException
Expression
This method must be overridden for any Expression that has subexpressions.
promote
in class Expression
offer
 details of the offer, for example the offer to move
expressions that don't depend on the context to an outer level in
the containing expressionparent
 the containing expression in the expression treeXPathException
 if any error is detectedpublic int computeSpecialProperties()
Expression
StaticProperty
. The "special" properties are properties
other than cardinality and dependencies, and most of them relate to properties of node sequences, for
example whether the nodes are in document order.computeSpecialProperties
in class Expression
public Expression copy()
copy
in class Expression
public ItemType getItemType()
Expression
This method should always return a result, though it may be the best approximation that is available at the time.
getItemType
in class Expression
public int computeCardinality()
Expression
computeCardinality
in class Expression
StaticProperty.ALLOWS_ZERO_OR_ONE
,
StaticProperty.EXACTLY_ONE
, StaticProperty.ALLOWS_ONE_OR_MORE
,
StaticProperty.ALLOWS_ZERO_OR_MORE
public 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 Expression
public boolean replaceOperand(Expression original, Expression replacement)
replaceOperand
in class Expression
original
 the original subexpressionreplacement
 the replacement subexpressionpublic Expression getBaseExpression()
public int getStart()
public boolean equals(Object other)
public StreamingAdjunct getStreamingAdjunct()
getStreamingAdjunct
in class Expression
public SequenceIterator iterate(XPathContext context) throws XPathException
Expression
iterate
in class Expression
context
 supplies the context for evaluationXPathException
 if any dynamic error occurs evaluating the
expressionpublic ExpressionCompiler getExpressionCompiler()
getExpressionCompiler
in class Expression
public void explain(ExpressionPresenter destination)
explain
in class Expression
destination
 the expression presenter used to display the structurepublic String toString()
The toString() method for an expression attempts to give a representation of the expression in an XPathlike 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 Expression
public String toShortString()
toShortString
in class Expression
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