| net.sf.saxon.functions.FunctionLibrary
All known Subclasses: net.sf.saxon.functions.ExecutableFunctionLibrary, net.sf.saxon.functions.SystemFunctionLibrary, net.sf.saxon.functions.ConstructorFunctionLibrary, net.sf.saxon.query.UnboundFunctionLibrary, net.sf.saxon.functions.JavaExtensionLibrary, net.sf.saxon.functions.VendorFunctionLibrary, net.sf.saxon.query.XQueryFunctionLibrary, net.sf.saxon.xpath.XPathFunctionLibrary, net.sf.saxon.style.StylesheetFunctionLibrary, net.sf.saxon.query.ImportedFunctionLibrary, net.sf.saxon.functions.FunctionLibraryList,
| FunctionLibrary | | public interface FunctionLibrary extends Serializable(Code) | | A FunctionLibrary handles the binding of function calls in XPath (or XQuery) expressions.
There are a number of implementations of this
class to handle different kinds of function: system functions, constructor functions, vendor-defined
functions, Java extension functions, stylesheet functions, and so on. There is also an implementation
net.sf.saxon.functions.FunctionLibraryList that allows a FunctionLibrary
to be constructed by combining other FunctionLibrary objects.
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| Method Summary | |
| public Expression | bind(int nameCode, String uri, String local, Expression[] staticArgs)
Bind an extension function, given the URI and local parts of the function name,
and the list of expressions supplied as arguments. | | public FunctionLibrary | copy()
This method creates a copy of a FunctionLibrary: if the original FunctionLibrary allows
new functions to be added, then additions to this copy will not affect the original, or
vice versa.
a copy of this function library. | | public boolean | isAvailable(int fingerprint, String uri, String local, int arity)
Test whether an extension function with a given name and arity is available. |
| bind | | public Expression bind(int nameCode, String uri, String local, Expression[] staticArgs) throws XPathException(Code) | | Bind an extension function, given the URI and local parts of the function name,
and the list of expressions supplied as arguments. This method is called at compile
time.
Parameters:
nameCode - The namepool nameCode of the function name. The uri and local name are alsosupplied (redundantly) to avoid fetching them from the name pool.
Parameters:
uri - The URI of the function name
Parameters:
local - The local part of the function name
Parameters:
staticArgs - The expressions supplied statically in arguments to the function call.The length of this array represents the arity of the function. The intention isthat the static type of the arguments (obtainable via getItemType() and getCardinality()) maybe used as part of the binding algorithm. In some cases it may be possible for the functionto be pre-evaluated at compile time, for example if these expressions are all constant values.The conventions of the XPath language demand that the results of a function depend only on thevalues of the expressions supplied as arguments, and not on the form of those expressions. Forexample, the result of f(4) is expected to be the same as f(2+2). The actual expression is suppliedhere to enable the binding mechanism to select the most efficient possible implementation (includingcompile-time pre-evaluation where appropriate). An object representing the function to be called, if one is found;null if no function was found matching the required name and arity.
throws:
net.sf.saxon.trans.XPathException - if a function is found with the required name and arity, butthe implementation of the function cannot be loaded or used; or if an error occurswhile searching for the function. |
| copy | | public FunctionLibrary copy()(Code) | | This method creates a copy of a FunctionLibrary: if the original FunctionLibrary allows
new functions to be added, then additions to this copy will not affect the original, or
vice versa.
a copy of this function library. This must be an instance of the original class. |
| isAvailable | | public boolean isAvailable(int fingerprint, String uri, String local, int arity)(Code) | | Test whether an extension function with a given name and arity is available. This supports
the function-available() function in XSLT. This method may be called either at compile time
or at run time. If the function library is to be used only in an XQuery or free-standing XPath
environment, this method may throw an UnsupportedOperationException.
Parameters:
fingerprint - The namepool fingerprint of the function name. This must match theuri and localName; the information is provided redundantly to avoid repeated lookups in the name pool.
Parameters:
uri - The URI of the function name
Parameters:
local - The local part of the function name
Parameters:
arity - The number of arguments. This is set to -1 in the case of the single-argumentfunction-available() function; in this case the method should return true if there is somematching extension function, regardless of its arity. |
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