Package net.sf.saxon.functions
Class JavaExtensionLibrary
- java.lang.Object
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- net.sf.saxon.functions.JavaExtensionLibrary
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- All Implemented Interfaces:
java.io.Serializable
,FunctionLibrary
public class JavaExtensionLibrary extends java.lang.Object implements 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:
- Serialized Form
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Constructor Summary
Constructors Constructor Description JavaExtensionLibrary(Configuration config)
Construct a JavaExtensionLibrary and establish the default uri->class mappings.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description protected int
atomicConversionPreference(int primitiveType, java.lang.Class required)
Get the conversion preference from an XPath primitive atomic type to a Java classExpression
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.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.void
declareJavaClass(java.lang.String uri, java.lang.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
setDefaultURIMappings()
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 Detail
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JavaExtensionLibrary
public JavaExtensionLibrary(Configuration config)
Construct a JavaExtensionLibrary and establish the default uri->class mappings.- Parameters:
config
- The Saxon configuration
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Method Detail
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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.
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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
public void declareJavaClass(java.lang.String uri, java.lang.Class theClass)
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
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.- 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
protected int atomicConversionPreference(int primitiveType, java.lang.Class required)
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
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.- 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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