net.sf.saxon.expr
public final class AxisExpression extends ComputedExpression
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 Reverser.
Field Summary | |
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int | computedCardinality |
Constructor Summary | |
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AxisExpression(byte axis, NodeTest nodeTest)
Constructor |
Method Summary | |
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int | computeCardinality()
Specify that the expression returns a singleton |
int | computeSpecialProperties()
Get the static properties of this expression (other than its type). |
void | display(int level, NamePool pool, PrintStream out)
Diagnostic print of expression structure |
boolean | equals(Object other)
Is this expression the same as another expression? |
byte | getAxis()
Get the axis |
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 |
SequenceIterator | iterate(XPathContext context)
Evaluate the path-expression in a given context to return a NodeSet |
Expression | optimize(Optimizer opt, StaticContext env, ItemType contextItemType)
Perform optimisation of an expression and its subexpressions.
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Expression | simplify(StaticContext env)
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(StaticContext env, ItemType contextItemType)
Type-check the expression |
Parameters: 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 acceptable
See Also: Axis
Parameters: th
Returns: Type.NODE or a subtype, based on the NodeTest in the axis step, plus information about the content type if this is known from schema analysis
Parameters: context the evaluation context
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.
Parameters: 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 expression contextItemType 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 ITEM_TYPE
Returns: the original expression, rewritten if appropriate to optimize execution
Returns: the simplified expression