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:
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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
(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.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
(StructuredQName functionName, 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).void
setStrictJavaUriFormat
(boolean strict) Indicate that only the strict "java:" URI format is to be recognized
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Constructor Details
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JavaExtensionLibrary
Construct a JavaExtensionLibrary and establish the default uri->class mappings.- Parameters:
config
- The Saxon configuration
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Method Details
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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. -
setStrictJavaUriFormat
public void setStrictJavaUriFormat(boolean strict) Indicate that only the strict "java:" URI format is to be recognized- Parameters:
strict
- true if only the strict format is recognized
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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
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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:
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- Returns:
- true if a function of this name and arity is available for calling.
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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.- Specified by:
bind
in interfaceFunctionLibrary
- Parameters:
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
- the static context- 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.
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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 exampleStandardNames.XS_STRING
orStandardNames.XS_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.
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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.
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