Package com.icl.saxon.expr
Class FilterExpression
java.lang.Object
com.icl.saxon.expr.Expression
com.icl.saxon.expr.NodeSetExpression
com.icl.saxon.expr.FilterExpression
A FilterExpression contains a base expression and a filter predicate, which may be an
integer expression (positional filter), or a boolean expression (qualifier)
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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 filter expression in a given context to return a Node Enumerationint
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
evaluate, 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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FilterExpression
Constructor- Parameters:
start
- A node-set expression denoting the absolute or relative set of nodes from which the navigation path should start.filter
- An expression defining the filter predicate
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Method Details
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simplify
Simplify an expression- Overrides:
simplify
in classExpression
- Returns:
- the simplified expression
- Throws:
XPathException
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enumerate
Evaluate the filter expression in a given context to return a Node Enumeration- Specified by:
enumerate
in classNodeSetExpression
- Parameters:
context
- the evaluation contextsort
- true if the result must be in document order- Throws:
XPathException
- when the expression does not return a nodeset.
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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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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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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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display
public void display(int level) Diagnostic print of expression structure- Specified by:
display
in classExpression
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