net.sf.saxon.functions
Class StringFn
java.lang.Object
net.sf.saxon.expr.ComputedExpression
net.sf.saxon.expr.FunctionCall
net.sf.saxon.functions.SystemFunction
net.sf.saxon.functions.StringFn
- All Implemented Interfaces:
- Serializable, Expression
public class StringFn
- extends SystemFunction
Implement XPath function string()
- See Also:
- Serialized Form
Methods inherited from class net.sf.saxon.functions.SystemFunction |
addContextDocumentArgument, checkArguments, computeCardinality, display, getDetails, getItemType, getName, getRequiredType, main, makeSystemFunction, useContextItemAsDefault |
Methods inherited from class net.sf.saxon.expr.ComputedExpression |
computeDependencies, computeSpecialProperties, computeStaticProperties, dynamicError, effectiveBooleanValue, evaluateAsString, getCardinality, getDependencies, getIntrinsicDependencies, getLineNumber, getSpecialProperties, iterate, markTailFunctionCalls, setLineNumber, typeError |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
StringFn
public StringFn()
simplify
public Expression simplify()
throws XPathException
- Simplify and validate.
This is a pure function so it can be simplified in advance if the arguments are known
- Specified by:
simplify
in interface Expression
- Overrides:
simplify
in class FunctionCall
- Returns:
- the simplified expression
- Throws:
XPathException
- if an error is discovered during expression
rewriting
analyze
public Expression analyze(StaticContext env)
throws XPathException
- Type check. This refinement of the method removes the function call wrapper if the
argument is already of type single string
- Specified by:
analyze
in interface Expression
- Overrides:
analyze
in class FunctionCall
- Parameters:
env
- the static context of the expression
- Returns:
- the original expression, rewritten to perform necessary
run-time type checks, and to perform other type-related
optimizations
- Throws:
XPathException
- if an error is discovered during this phase
(typically a type error)
evaluateItem
public Item evaluateItem(XPathContext c)
throws XPathException
- Evaluate the function
- Specified by:
evaluateItem
in interface Expression
- Overrides:
evaluateItem
in class ComputedExpression
- Parameters:
c
- The context in which the expression is to be evaluated
- Returns:
- the node or atomic value that results from evaluating the
expression; or null to indicate that the result is an empty
sequence
- Throws:
XPathException
- if any dynamic error occurs evaluating the
expression