Package com.icl.saxon.expr
Class AxisExpression
java.lang.Object
com.icl.saxon.expr.Expression
com.icl.saxon.expr.NodeSetExpression
com.icl.saxon.expr.AxisExpression
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*".
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Field Summary
Fields inherited from class com.icl.saxon.expr.Expression
staticContext
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionvoid
display
(int level) Diagnostic print of expression structureEvaluate the path-expression in a given context to return a NodeSetEvaluate the expression (typically used if the result is to be stored in a variable)int
Determine which aspects of the context the expression depends on.boolean
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.Perform a partial evaluation of the expression, by eliminating specified dependencies on the context.simplify()
Simplify an expressionMethods inherited from class com.icl.saxon.expr.NodeSetExpression
evaluateAsBoolean, evaluateAsNodeSet, evaluateAsString, getDataType, outputStringValue, selectFirst
Methods inherited from class com.icl.saxon.expr.Expression
containsReferences, evaluateAsNumber, getStaticContext, indent, make, setStaticContext, usesCurrent
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Constructor Details
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AxisExpression
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
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Method Details
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simplify
Simplify an expression- Overrides:
simplify
in classExpression
- Returns:
- the simplified expression
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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- Specified by:
getDependencies
in classExpression
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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.- Overrides:
isContextDocumentNodeSet
in classExpression
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reduce
Perform a partial evaluation of the expression, by eliminating specified dependencies on the context.- Specified by:
reduce
in classExpression
- Parameters:
dep
- The dependencies to be removedcontext
- The context to be used for the partial evaluation- Returns:
- a new expression that does not have any of the specified dependencies
- Throws:
XPathException
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enumerate
Evaluate the path-expression in a given context to return a NodeSet- Specified by:
enumerate
in classNodeSetExpression
- Parameters:
context
- the evaluation contextsort
- true if the returned nodes must be in document order- Throws:
XPathException
- when the expression does not return a nodeset.
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evaluate
Evaluate the expression (typically used if the result is to be stored in a variable)- Overrides:
evaluate
in classNodeSetExpression
- Parameters:
context
- The context in which the expression is to be evaluated- Returns:
- the value of the expression, evaluated in the current context
- Throws:
XPathException
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display
public void display(int level) Diagnostic print of expression structure- Specified by:
display
in classExpression
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