public final class AxisExpression extends Expression
An AxisExpression delivers nodes in axis order (not in document order). To get nodes in document order, in the case of a reverse axis, the expression should be wrapped in a call on reverse().
Modifier and Type | Field and Description |
---|---|
(package private) int |
computedCardinality |
EVALUATE_METHOD, EVENT_FEED_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, locationId, PROCESS_METHOD, PUSH_SELECTION, staticProperties, WATCH_METHOD
Constructor and Description |
---|
AxisExpression(byte axis,
NodeTest nodeTest)
Constructor
|
Modifier and Type | Method and Description |
---|---|
PathMap.PathMapNodeSet |
addToPathMap(PathMap pathMap,
PathMap.PathMapNodeSet pathMapNodeSet)
Add a representation of this expression to a PathMap.
|
int |
computeCardinality()
Determine the cardinality of the result of this expression
|
int |
computeSpecialProperties()
Get the static properties of this expression (other than its type).
|
Expression |
copy()
Copy an expression.
|
boolean |
equals(Object other)
Is this expression the same as another expression?
|
void |
explain(ExpressionPresenter destination)
Diagnostic print of expression structure.
|
byte |
getAxis()
Get the axis
|
ItemType |
getContextItemType()
Get the static type of the context item for this AxisExpression.
|
String |
getExpressionName()
Get a name identifying the kind of expression, in terms meaningful to a user.
|
int |
getIntrinsicDependencies()
Determine which aspects of the context the expression depends on.
|
ItemType |
getItemType(TypeHierarchy th)
Determine the data type of the items returned by this expression
|
NodeTest |
getNodeTest()
Get the NodeTest.
|
int |
hashCode()
get HashCode for comparing two expressions
|
boolean |
isSubtreeExpression()
Determine whether the expression can be evaluated without reference to the part of the context
document outside the subtree rooted at the context node.
|
SequenceIterator |
iterate(Item origin)
Iterate the axis from a given starting node, without regard to context
|
SequenceIterator |
iterate(XPathContext context)
Evaluate the path-expression in a given context to return a NodeSet
|
Expression |
optimize(ExpressionVisitor visitor,
ItemType contextItemType)
Perform optimisation of an expression and its subexpressions.
|
Expression |
simplify(ExpressionVisitor visitor)
Simplify an expression
|
String |
toString()
Represent the expression as a string for diagnostics
|
String |
toString(NamePool pool)
Represent the expression as a string for diagnostics
|
Expression |
typeCheck(ExpressionVisitor visitor,
ItemType contextItemType)
Type-check the expression
|
adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, evaluatePendingUpdates, explain, getCardinality, getColumnNumber, getColumnNumber, getConstructType, getContainer, getDependencies, getEvaluationMethod, getExecutable, getHostLanguage, getImplementationMethod, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, isUpdatingExpression, isVacuousExpression, iterateEvents, iterateSameFocusSubExpressions, iterateSubExpressions, markTailFunctionCalls, process, promote, replaceSubExpression, resetLocalStaticProperties, setContainer, setEvaluationMethod, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, typeError
public AxisExpression(byte axis, NodeTest nodeTest)
axis
- The axis to be used in this AxisExpression: relevant constants are defined
in class net.sf.saxon.om.Axis.nodeTest
- The conditions to be satisfied by selected nodes. May be null,
indicating that any node on the axis is acceptableAxis
public String getExpressionName()
getExpressionName
in class Expression
public Expression simplify(ExpressionVisitor visitor)
simplify
in class Expression
visitor
- an expression visitorpublic Expression typeCheck(ExpressionVisitor visitor, ItemType contextItemType) throws XPathException
typeCheck
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 ItemType getContextItemType()
public Expression optimize(ExpressionVisitor visitor, ItemType contextItemType)
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
public boolean equals(Object other)
public int hashCode()
public int getIntrinsicDependencies()
getIntrinsicDependencies
in class Expression
public Expression copy()
copy
in class Expression
public int computeSpecialProperties()
computeSpecialProperties
in class Expression
public final ItemType getItemType(TypeHierarchy th)
getItemType
in class Expression
th
- the type hierarchy cachepublic final int computeCardinality()
computeCardinality
in class Expression
StaticProperty.ALLOWS_ZERO_OR_ONE
,
StaticProperty.EXACTLY_ONE
, StaticProperty.ALLOWS_ONE_OR_MORE
,
StaticProperty.ALLOWS_ZERO_OR_MORE
public boolean isSubtreeExpression()
isSubtreeExpression
in class Expression
public byte getAxis()
Axis.CHILD
public NodeTest getNodeTest()
public PathMap.PathMapNodeSet addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet)
addToPathMap
in class Expression
pathMap
- the PathMap to which the expression should be addedpathMapNodeSet
- public SequenceIterator iterate(XPathContext context) throws XPathException
iterate
in interface SequenceIterable
iterate
in class Expression
context
- the evaluation contextXPathException
- if any dynamic error occurs evaluating the
expressionpublic SequenceIterator iterate(Item origin) throws XPathException
origin
- the starting nodeXPathException
public void explain(ExpressionPresenter destination)
explain
in class Expression
destination
- the expression presenter used to display the structurepublic String toString()
toString
in class Expression