net.sf.saxon.functions
Class JavaExtensionLibrary
java.lang.Object
net.sf.saxon.functions.JavaExtensionLibrary
- FunctionLibrary, Serializable
public class JavaExtensionLibrary
extends java.lang.Object
The JavaExtensionLibrary is a FunctionLibrary that binds XPath function calls to
calls on Java methods (or constructors, or fields). It performs a mapping from
the namespace URI of the function to the Java class (the mapping is partly table
driven and partly algorithmic), and maps the local name of the function to the
Java method, constructor, or field within the class. If the Java methods are
polymorphic, then it tries to select the appropriate method based on the static types
of the supplied arguments. Binding is done entirely at XPath compilation time.
protected int | atomicConversionPreference(int primitiveType, Class required) - Get the conversion preference from an XPath primitive atomic type to a Java class
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Expression | bind(StructuredQName functionName, Expression[] staticArgs, StaticContext env) - Bind an extension function, given the URI and local parts of the function name,
and the list of expressions supplied as arguments.
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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.
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void | declareJavaClass(String uri, Class theClass) - Declare a mapping from a specific namespace URI to a Java class
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boolean | isAvailable(StructuredQName functionName, int arity) - Test whether an extension function with a given name and arity is available.
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protected void | setDefaultURIMappings() - Define initial mappings of "well known" namespace URIs to Java classes (this covers
the Saxon and EXSLT extensions).
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JavaExtensionLibrary
public JavaExtensionLibrary(Configuration config)
Construct a JavaExtensionLibrary and establish the default uri->class mappings.
config
- The Saxon configuration
atomicConversionPreference
protected int atomicConversionPreference(int primitiveType,
Class required)
Get the conversion preference from an XPath primitive atomic type to a Java class
- an integer indicating the relative preference for converting this primitive type
to this Java class. A high number indicates a low preference. All values are in the range
50 to 100. For example, the conversion of an XPath String to
StringValue
is 50, while
XPath String to java.lang.String
is 51. The value -1 indicates that the conversion is not allowed.
bind
public Expression bind(StructuredQName functionName,
Expression[] staticArgs,
StaticContext env)
throws XPathException
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.
- bind in interface FunctionLibrary
functionName
- the qualified name of the function being calledstaticArgs
- The expressions supplied statically in the function call. The intention is
that the static type of the arguments (obtainable via getItemType() and getCardinality()) may
be used as part of the binding algorithm.env
-
- An object representing the extension function to be called, if one is found;
null if no extension function was found matching the required name, arity, or signature.
copy
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.
- copy in interface FunctionLibrary
- a copy of this function library. This must be an instance of the original class.
declareJavaClass
public void declareJavaClass(String uri,
Class theClass)
Declare a mapping from a specific namespace URI to a Java class
uri
- the namespace URI of the function nametheClass
- the Java class that implements the functions in this namespace
isAvailable
public boolean isAvailable(StructuredQName functionName,
int arity)
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.
- isAvailable in interface FunctionLibrary
functionName
- The qualified name of the extension functionarity
- The number of arguments. This is set to -1 in the case of the single-argument
function-available() function; in this case the method should return true if there is some
setDefaultURIMappings
protected void setDefaultURIMappings()
Define initial mappings of "well known" namespace URIs to Java classes (this covers
the Saxon and EXSLT extensions). The method is protected so it can be overridden in
a subclass.