com.icl.saxon.expr

Class AxisExpression

final class AxisExpression extends NodeSetExpression

An AxisExpression is always obtained by simplifying a PathExpression. It represents a PathExpression that starts at the context node, and uses a simple node-test with no filters. For example "*", "title", "./item", "@*", or "ancestor::chapter*".
Constructor Summary
AxisExpression(byte axis, NodeTest nodeTest)
Constructor
Method Summary
voiddisplay(int level)
Diagnostic print of expression structure
NodeEnumerationenumerate(Context context, boolean sort)
Evaluate the path-expression in a given context to return a NodeSet
Valueevaluate(Context context)
Evaluate the expression (typically used if the result is to be stored in a variable)
intgetDependencies()
Determine which aspects of the context the expression depends on.
booleanisContextDocumentNodeSet()
Determine, in the case of an expression whose data type is Value.NODESET, whether all the nodes in the node-set are guaranteed to come from the same document as the context node.
Expressionreduce(int dep, Context context)
Perform a partial evaluation of the expression, by eliminating specified dependencies on the context.
Expressionsimplify()
Simplify an expression

Constructor Detail

AxisExpression

public AxisExpression(byte axis, NodeTest nodeTest)
Constructor

Parameters: 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-set

Method Detail

display

public void display(int level)
Diagnostic print of expression structure

enumerate

public NodeEnumeration enumerate(Context context, boolean sort)
Evaluate the path-expression in a given context to return a NodeSet

Parameters: context the evaluation context sort true if the returned nodes must be in document order

evaluate

public Value evaluate(Context context)
Evaluate the expression (typically used if the result is to be stored in a variable)

getDependencies

public int getDependencies()
Determine which aspects of the context the expression depends on. The result is a bitwise-or'ed value composed from constants such as Context.VARIABLES and Context.CURRENT_NODE

isContextDocumentNodeSet

public boolean isContextDocumentNodeSet()
Determine, in the case of an expression whose data type is Value.NODESET, whether all the nodes in the node-set are guaranteed to come from the same document as the context node. Used for optimization.

reduce

public Expression reduce(int dep, Context context)
Perform a partial evaluation of the expression, by eliminating specified dependencies on the context.

Parameters: dep The dependencies to be removed context The context to be used for the partial evaluation

Returns: a new expression that does not have any of the specified dependencies

simplify

public Expression simplify()
Simplify an expression

Returns: the simplified expression