java.io.Serializable
, javax.xml.transform.SourceLocator
, Container
, ContextMappingFunction
, Expression
, InstructionInfoProvider
public final class PathExpression extends ComputedExpression implements ContextMappingFunction
locationId, staticProperties
EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD
Constructor | Description |
---|---|
PathExpression(Expression start,
Expression step) |
Constructor
|
Modifier and Type | Method | Description |
---|---|---|
int |
computeCardinality() |
Determine the static cardinality of the expression
|
int |
computeDependencies() |
Determine which aspects of the context the expression depends on.
|
int |
computeSpecialProperties() |
Get the static properties of this expression (other than its type).
|
void |
display(int level,
java.io.PrintStream out,
Configuration config) |
Diagnostic print of expression structure
|
boolean |
equals(java.lang.Object other) |
Is this expression the same as another expression?
|
Expression |
getFirstStep() |
Get the first step in this expression.
|
ItemType |
getItemType(TypeHierarchy th) |
Determine the data type of the items returned by this exprssion
|
Expression |
getLastStep() |
Get the last step of the path expression
|
Expression |
getLeadingSteps() |
Get a path expression consisting of all steps except the last
|
Expression |
getRemainingSteps() |
Get all steps after the first.
|
Expression |
getStartExpression() |
Get the start expression (the left-hand operand)
|
Expression |
getStepExpression() |
Get the step expression (the right-hand operand)
|
int |
hashCode() |
get HashCode for comparing two expressions
|
boolean |
isAbsolute(TypeHierarchy th) |
Test whether a path expression is an absolute path - that is, a path whose first step selects a
document node
|
SequenceIterator |
iterate(XPathContext context) |
Iterate the path-expression in a given context
|
java.util.Iterator |
iterateSubExpressions() |
Get the immediate subexpressions of this expression
|
SequenceIterator |
map(XPathContext context) |
Mapping function, from a node returned by the start iteration, to a sequence
returned by the child.
|
Expression |
optimize(Optimizer opt,
StaticContext env,
ItemType contextItemType) |
Optimize the expression and perform type analysis
|
Expression |
promote(PromotionOffer offer) |
Promote this expression if possible
|
boolean |
replaceSubExpression(Expression original,
Expression replacement) |
Replace one subexpression by a replacement subexpression
|
Expression |
simplify(StaticContext env) |
Simplify an expression
|
Expression |
typeCheck(StaticContext env,
ItemType contextItemType) |
Optimize the expression and perform type analysis
|
adoptChildExpression, checkPermittedContents, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, getCardinality, getColumnNumber, getConstructType, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getInstructionInfo, getIntrinsicDependencies, getLineNumber, getLocationId, getLocationProvider, getParentExpression, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasBadParentPointer, markTailFunctionCalls, process, resetStaticProperties, setLocationId, setParentExpression, setParentExpression, suppressValidation, typeError
public PathExpression(Expression start, Expression step)
start
- A node-set expression denoting the absolute or relative set of nodes from which the
navigation path should start.step
- The step to be followed from each node in the start expression to yield a new
node-setpublic Expression getStartExpression()
public Expression getStepExpression()
public final ItemType getItemType(TypeHierarchy th)
getItemType
in interface Expression
th
- public Expression simplify(StaticContext env) throws XPathException
simplify
in interface Expression
simplify
in class ComputedExpression
env
- the static contextXPathException
- if an error is discovered during expression
rewritingpublic Expression typeCheck(StaticContext env, ItemType contextItemType) throws XPathException
typeCheck
in interface Expression
env
- the static context of the expressioncontextItemType
- 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
StaticError
- if an error is discovered during this phase
(typically a type error)XPathException
public Expression optimize(Optimizer opt, StaticContext env, ItemType contextItemType) throws XPathException
optimize
in interface Expression
opt
- the optimizer in use. This provides access to supporting functions; it also allows
different optimization strategies to be used in different circumstances.env
- the static context of the expressioncontextItemType
- 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
StaticError
- if an error is discovered during this phase
(typically a type error)XPathException
public Expression promote(PromotionOffer offer) throws XPathException
promote
in interface Expression
promote
in class ComputedExpression
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 expressionXPathException
- if any error is detectedpublic java.util.Iterator iterateSubExpressions()
iterateSubExpressions
in interface Expression
iterateSubExpressions
in class ComputedExpression
public boolean replaceSubExpression(Expression original, Expression replacement)
replaceSubExpression
in interface Container
replaceSubExpression
in class ComputedExpression
original
- the original subexpressionreplacement
- the replacement subexpressionpublic int computeDependencies()
computeDependencies
in class ComputedExpression
public int computeSpecialProperties()
computeSpecialProperties
in class ComputedExpression
public int computeCardinality()
computeCardinality
in class ComputedExpression
public boolean equals(java.lang.Object other)
equals
in class java.lang.Object
public int hashCode()
hashCode
in class java.lang.Object
public Expression getFirstStep()
public Expression getRemainingSteps()
public Expression getLastStep()
public Expression getLeadingSteps()
public boolean isAbsolute(TypeHierarchy th)
public SequenceIterator iterate(XPathContext context) throws XPathException
iterate
in interface Expression
iterate
in class ComputedExpression
context
- the evaluation contextXPathException
- if any dynamic error occurs evaluating the
expressionpublic SequenceIterator map(XPathContext context) throws XPathException
map
in interface ContextMappingFunction
context
- The processing context. The item to be mapped is the context item identified
from this context: the values of position() and last() also relate to the set of items being mappedXPathException
public void display(int level, java.io.PrintStream out, Configuration config)
display
in interface Expression
level
- indentation level for this expressionout
- Output destination