Package net.sf.saxon.functions
Class JavaExtensionLibrary
java.lang.Object
net.sf.saxon.functions.JavaExtensionLibrary
- All Implemented Interfaces:
Serializable
,FunctionLibrary
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.
- See Also:
-
Constructor Summary
ConstructorsConstructorDescriptionJavaExtensionLibrary
(Configuration config) Construct a JavaExtensionLibrary and establish the default uri->class mappings. -
Method Summary
Modifier and TypeMethodDescriptionprotected int
atomicConversionPreference
(int primitiveType, Class required) Get the conversion preference from an XPath primitive atomic type to a Java classbind
(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.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.void
declareJavaClass
(String uri, Class theClass) Declare a mapping from a specific namespace URI to a Java classboolean
isAvailable
(int fingerprint, String uri, String local, int arity) Test whether an extension function with a given name and arity is available.protected void
Define initial mappings of "well known" namespace URIs to Java classes (this covers the Saxon and EXSLT extensions).static String
toCamelCase
(String name, boolean debug, PrintStream diag) Convert a name to camelCase (by removing hyphens and changing the following letter to capitals)
-
Constructor Details
-
JavaExtensionLibrary
Construct a JavaExtensionLibrary and establish the default uri->class mappings.- Parameters:
config
- The Saxon configuration
-
-
Method Details
-
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. -
declareJavaClass
Declare a mapping from a specific namespace URI to a Java class- Parameters:
uri
- the namespace URI of the function nametheClass
- the Java class that implements the functions in this namespace
-
isAvailable
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.- Specified by:
isAvailable
in interfaceFunctionLibrary
- Parameters:
fingerprint
- The code that identifies the function name in the NamePool. This must match the supplied URI and local name.uri
- The URI of the function namelocal
- The local part of the function namearity
- 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 matching extension function, regardless of its arity.
-
bind
public Expression bind(int nameCode, String uri, String local, Expression[] staticArgs) 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.- Specified by:
bind
in interfaceFunctionLibrary
- Parameters:
nameCode
- The namepool code of the function name. This must match the supplied URI and local name.uri
- The URI of the function namelocal
- The local part of the function namestaticArgs
- 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.- Returns:
- 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.
- Throws:
XPathException
- if a function is found with the required name and arity, but the implementation of the function cannot be loaded or used; or if an error occurs while searching for the function.
-
toCamelCase
Convert a name to camelCase (by removing hyphens and changing the following letter to capitals)- Parameters:
name
- the name to be converted to camelCasedebug
- true if tracing is required- Returns:
- the camelCased name
-
atomicConversionPreference
Get the conversion preference from an XPath primitive atomic type to a Java class- Parameters:
primitiveType
- integer code identifying the XPath primitive type, for exampleType.INTEGER
orType.STRING
required
- The Java Class named in the method signature- Returns:
- 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 toString
is 51. The value -1 indicates that the conversion is not allowed.
-
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.- Specified by:
copy
in interfaceFunctionLibrary
- Returns:
- a copy of this function library. This must be an instance of the original class.
-