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java.lang.Object net.sf.saxon.expr.Expression net.sf.saxon.expr.FunctionCall net.sf.saxon.functions.SystemFunction net.sf.saxon.functions.StringFn
public class StringFn
Implement XPath function string()
Field Summary |
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Fields inherited from class net.sf.saxon.functions.SystemFunction |
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operation |
Fields inherited from class net.sf.saxon.expr.FunctionCall |
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argument |
Fields inherited from class net.sf.saxon.expr.Expression |
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EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, EVENT_FEED_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, locationId, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, PROCESS_METHOD, PUSH_SELECTION, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, WATCH_METHOD |
Constructor Summary | |
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StringFn()
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Method Summary | |
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PathMap.PathMapNodeSet |
addToPathMap(PathMap pathMap,
PathMap.PathMapNodeSet pathMapNodeSet)
Add a representation of this expression to a PathMap. |
Item |
evaluateItem(XPathContext c)
Evaluate the function |
int |
getImplementationMethod()
An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process(). |
Expression |
optimize(ExpressionVisitor visitor,
ExpressionVisitor.ContextItemType contextItemType)
Perform optimisation of an expression and its subexpressions. |
Expression |
simplify(ExpressionVisitor visitor)
Simplify and validate. |
Methods inherited from class net.sf.saxon.functions.SystemFunction |
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addContextDocumentArgument, addDocToPathMap, checkArguments, computeCardinality, computeSpecialProperties, copy, equals, getDetails, getErrorCodeForTypeErrors, getItemType, getOperation, getRequiredType, makeSystemFunction, setDetails, useContextItemAsDefault |
Methods inherited from class net.sf.saxon.expr.FunctionCall |
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addExternalFunctionCallToPathMap, checkArgumentCount, explain, getArguments, getDisplayName, getExpressionName, getFunctionName, getNumberOfArguments, hashCode, iterateSubExpressions, preEvaluate, promote, replaceSubExpression, setArguments, setFunctionName, simplifyArguments, toString, typeCheck |
Methods inherited from class java.lang.Object |
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clone, finalize, getClass, notify, notifyAll, wait, wait, wait |
Constructor Detail |
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public StringFn()
Method Detail |
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public int getImplementationMethod()
getImplementationMethod
in class SystemFunction
Expression.ITERATE_METHOD
or Expression.EVALUATE_METHOD
or
Expression.PROCESS_METHOD
public Expression simplify(ExpressionVisitor visitor) throws XPathException
simplify
in class FunctionCall
visitor
- an expression visitor
XPathException
- if an error is discovered during expression
rewritingpublic Expression optimize(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) throws XPathException
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.
optimize
in class SystemFunction
visitor
- an expression visitorcontextItemType
- 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
Type.ITEM_TYPE
XPathException
- if an error is discovered during this phase
(typically a type error)public PathMap.PathMapNodeSet addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet)
The default implementation of this method assumes that an expression does no navigation other than the navigation done by evaluating its subexpressions, and that the subexpressions are evaluated in the same context as the containing expression. The method must be overridden for any expression where these assumptions do not hold. For example, implementations exist for AxisExpression, ParentExpression, and RootExpression (because they perform navigation), and for the doc(), document(), and collection() functions because they create a new navigation root. Implementations also exist for PathExpression and FilterExpression because they have subexpressions that are evaluated in a different context from the calling expression.
addToPathMap
in class Expression
pathMap
- the PathMap to which the expression should be addedpathMapNodeSet
- the PathMapNodeSet to which the paths embodied in this expression should be added
public Item evaluateItem(XPathContext c) throws XPathException
evaluateItem
in class Expression
c
- The context in which the expression is to be evaluated
XPathException
- if any dynamic error occurs evaluating the
expression
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