Package com.saxonica.config
Class JavaExtensionLibrary
java.lang.Object
com.saxonica.config.JavaExtensionLibrary
- All Implemented Interfaces:
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.
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Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionclass
Inner class representing an unresolved extension function call. -
Constructor Summary
ConstructorsConstructorDescriptionConstruct 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
(SymbolicName.F symbolicName, Expression[] staticArgs, Map<StructuredQName, Integer> keywords, StaticContext env, List<String> reasons) 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 classGet the ExtensionFunctionFactory used by this extension library.protected Class
getExternalJavaClass
(String uri, String localName, boolean debug) Get an external Java class corresponding to a given namespace URI, if there is one.getFunctionItem
(SymbolicName.F functionName, StaticContext staticContext) Test whether a function with a given name and arity is available; if so, return a function item that can be dynamically called.protected String
getMethodNameFromLocalName
(String uri, String localName, boolean debug) Get the Java method/field name from the local name used in the function call.boolean
isAvailable
(SymbolicName.F functionName, int languageLevel) Test whether a function with a given name and arity is availableboolean
Ask whether only the strict "java:" URI format is to be recognized.void
Set the ExtensionFunctionFactory to be used by this extension library.void
setStrictJavaUriFormat
(boolean strict) Say that only the strict "java:" URI format is to be recognized.Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Methods inherited from interface net.sf.saxon.functions.FunctionLibrary
setConfiguration
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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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setExtensionFunctionFactory
Set the ExtensionFunctionFactory to be used by this extension library.- Parameters:
factory
- This must be an instanceof JavaExtensionFunctionFactory
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getExtensionFunctionFactory
Get the ExtensionFunctionFactory used by this extension library.- Returns:
- the factory, which will always be an instanceof JavaExtensionFunctionFactory
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isStrictJavaUriFormat
public boolean isStrictJavaUriFormat()Ask whether only the strict "java:" URI format is to be recognized. The default is "true": the value false can be set for backwards compatibility with releases before Saxon 9.2- Returns:
- true if only the strict format is recognized
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setStrictJavaUriFormat
public void setStrictJavaUriFormat(boolean strict) Say that only the strict "java:" URI format is to be recognized. The default is "true": the value false can be set for backwards compatibility with releases before Saxon 9.2- 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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getFunctionItem
public FunctionItem getFunctionItem(SymbolicName.F functionName, StaticContext staticContext) throws XPathException Test whether a function with a given name and arity is available; if so, return a function item that can be dynamically called.This supports the function-lookup() function in XPath 3.0.
- Specified by:
getFunctionItem
in interfaceFunctionLibrary
- Parameters:
functionName
- the qualified name of the function being calledstaticContext
- the static context to be used by the function, in the event that it is a system function with dependencies on the static context- Returns:
- if a function of this name and arity is available for calling, then a corresponding function item; or null if the function does not exist
- Throws:
XPathException
- in the event of certain errors, for example attempting to get a function that is private
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isAvailable
Test whether a function with a given name and arity is availableThis supports the function-available() function in XSLT.
- Specified by:
isAvailable
in interfaceFunctionLibrary
- Parameters:
functionName
- the qualified name of the function being calledlanguageLevel
- the XPath language level times 10 (31=XPath 3.1)- Returns:
- true if a function of this name and arity is available for calling
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bind
public Expression bind(SymbolicName.F symbolicName, Expression[] staticArgs, Map<StructuredQName, Integer> keywords, StaticContext env, List<String> reasons) 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:
symbolicName
- the qualified name and arity 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.keywords
- May be null if no keywords are used in the function call. Otherwise, a map identifying the keywords appearing in the function call, and the 0-based position at which they appeared.env
- the static contextreasons
- If no matching function is found by the function library, it may add a diagnostic explanation to this list explaining why none of the available functions could be used.- 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.
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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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getExternalJavaClass
Get an external Java class corresponding to a given namespace URI, if there is one. The method is protected so it can be overridden in a user-defined subclass.- Parameters:
uri
- The namespace URI corresponding to the prefix used in the function call.localName
- The local name of the function, in case this contributes to determining the classdebug
- true if tracing information should be output- Returns:
- the Java class name if a suitable class exists, otherwise return null.
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getMethodNameFromLocalName
Get the Java method/field name from the local name used in the function call. This may be overridden in a subclass. The default implementation is as follows: if the URI is NamespaceConstant.JAVA_TYPE, the method name is that part of the local name appearing after the last dot/period. Otherwise, it is the local-name, converted to camel-case by removing hyphens and converting any character immediately following a hyphen to upper case.- Parameters:
uri
- the namespace URI used in the function calllocalName
- the local name used in the function calldebug
- true if tracing is requested- Returns:
- the local name of the method or field
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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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