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java.lang.Object net.sf.saxon.query.XQueryFunctionLibrary
public class XQueryFunctionLibrary
An XQueryFunctionLibrary is a function library containing all the user-defined functions available for use within a particular XQuery module: that is, the functions declared in that module, and the functions imported from other modules. It also contains (transiently during compilation) a list of function calls within the module that have not yet been bound to a specific function declaration.
Constructor Summary | |
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XQueryFunctionLibrary(Configuration config)
Create an XQueryFunctionLibrary |
Method Summary | |
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Expression |
bind(StructuredQName functionName,
Expression[] arguments,
StaticContext env,
Container container)
Identify a (namespace-prefixed) function appearing in the expression. |
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 |
declareFunction(XQueryFunction function)
Register a user-defined XQuery function |
void |
explainGlobalFunctions(ExpressionPresenter out)
Output "explain" information about each declared function |
protected void |
fixupGlobalFunctions(QueryModule env)
Fixup all references to global functions. |
Configuration |
getConfiguration()
Get the Configuration options |
XQueryFunction |
getDeclaration(StructuredQName functionName,
Expression[] staticArgs)
Get the function declaration corresponding to a given function name and arity |
XQueryFunction |
getDeclarationByKey(String functionKey)
Get the function declaration corresponding to a given function name and arity, supplied in the form "{uri}local/arity" |
Iterator<XQueryFunction> |
getFunctionDefinitions()
Get an iterator over the Functions defined in this module |
SequenceType[] |
getFunctionSignature(StructuredQName functionName,
int arity)
Test whether a function with a given name and arity is available; if so, return its signature. |
UserFunction |
getUserDefinedFunction(String uri,
String localName,
int arity)
Get the function with a given name and arity. |
protected void |
optimizeGlobalFunctions()
Optimize the body of all global functions. |
void |
setConfiguration(Configuration config)
Set the Configuration options |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
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public XQueryFunctionLibrary(Configuration config)
config
- the Saxon configurationMethod Detail |
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public void setConfiguration(Configuration config)
config
- the Saxon configurationpublic Configuration getConfiguration()
public void declareFunction(XQueryFunction function) throws XPathException
function
- the function to be registered
XPathException
- if there is an existing function with the same name and aritypublic SequenceType[] getFunctionSignature(StructuredQName functionName, int arity)
This method may be called either at compile time or at run time. If the function library is to be used only in an XQuery or free-standing XPath environment, this method may throw an UnsupportedOperationException.
getFunctionSignature
in interface FunctionLibrary
functionName
- the qualified name of the function being calledarity
- 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
function of this name available for calling.
public Expression bind(StructuredQName functionName, Expression[] arguments, StaticContext env, Container container) throws XPathException
Note that a function call may appear earlier in the query than the definition of the function to which it is bound. Unlike XSLT, we cannot search forwards to find the function definition. Binding of function calls is therefore a two-stage process; at the time the function call is parsed, we simply register it as pending; subsequently at the end of query parsing all the pending function calls are resolved. Another consequence of this is that we cannot tell at the time a function call is parsed whether it is a call to an internal (XSLT or XQuery) function or to an extension function written in Java.
bind
in interface FunctionLibrary
functionName
- the QName of the function being calledarguments
- The expressions supplied statically in arguments to the function call.
The length of this array represents the arity of the function. The intention is
that the static type of the arguments (obtainable via getItemType() and getCardinality()) may
be used as part of the binding algorithm. In some cases it may be possible for the function
to be pre-evaluated at compile time, for example if these expressions are all constant values.
The conventions of the XPath language demand that the results of a function depend only on the values of the expressions supplied as arguments, and not on the form of those expressions. For example, the result of f(4) is expected to be the same as f(2+2). The actual expression is supplied here to enable the binding mechanism to select the most efficient possible implementation (including compile-time pre-evaluation where appropriate).
env
- The static context of the function callcontainer
- The container for the newly created Expression
XPathException
- if the function call is invalid, either because it is
an unprefixed call to a non-system function, or because it is calling a system
function that is available in XSLT only. A prefixed function call that cannot
be recognized at this stage is assumed to be a forwards reference, and is bound
later when bindUnboundFunctionCalls() is called.public XQueryFunction getDeclaration(StructuredQName functionName, Expression[] staticArgs)
getDeclaration
in interface XQueryFunctionBinder
functionName
- the name of the function as a QNamestaticArgs
- the expressions supplied as arguments in the function call (typically,
we only need to know the number of arguments)
public XQueryFunction getDeclarationByKey(String functionKey)
functionKey
- a string in the form "{uri}local/arity" identifying the required function
public Iterator<XQueryFunction> getFunctionDefinitions()
XQueryFunction
objects. It returns
all function known to this module including those imported from elsewhere; they
can be distinguished by their namespace.protected void fixupGlobalFunctions(QueryModule env) throws XPathException
This method is for internal use.
env
- the static context for the main query body.
XPathException
protected void optimizeGlobalFunctions() throws XPathException
XPathException
public void explainGlobalFunctions(ExpressionPresenter out)
out
- the ExpressionPresenter that renders the outputpublic UserFunction getUserDefinedFunction(String uri, String localName, int arity)
uri
- the uri of the function namelocalName
- the local part of the function namearity
- the number of arguments.
public FunctionLibrary copy()
copy
in interface FunctionLibrary
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