net.sf.saxon.expr
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().
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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PathMap.PathMapNodeSet | addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet)
Add a representation of this expression to a PathMap. |
int | computeCardinality()
Specify that the expression returns a singleton |
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. |
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(XPathContext context)
Evaluate the path-expression in a given context to return a NodeSet |
SequenceIterator | iterate(Item origin)
Iterate the axis from a given starting node, without regard to context |
Expression | optimize(ExpressionVisitor visitor, ItemType contextItemType)
Perform optimisation of an expression and its subexpressions.
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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 |
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: pathMap the PathMap to which the expression should be added pathMapNodeSet
Returns: the pathMapNode representing the focus established by this expression, in the case where this expression is the first operand of a path expression or filter expression
Returns: the copy of the original expression
Returns: the axis number, for example CHILD
Returns: the statically-inferred type, or null if not known
Parameters: th the type hierarchy cache
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
Returns: the node test, or null if all nodes are returned
Returns: true if the expression has no dependencies on the context node, or if the only dependencies on the context node are downward selections using the self, child, descendant, attribute, and namespace axes.
Parameters: context the evaluation context
Parameters: origin the starting node
Returns: the iterator over the axis
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: visitor an expression visitor 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
Parameters: visitor an expression visitor
Returns: the simplified expression
Parameters: pool the name pool, used for expanding names in the node test
Returns: a string representation of the expression