net.sf.saxon.query.XQueryFunctionLibrary Maven / Gradle / Ivy
Show all versions of Saxon-HE Show documentation
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2015 Saxonica Limited.
// This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
// If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
// This Source Code Form is "Incompatible With Secondary Licenses", as defined by the Mozilla Public License, v. 2.0.
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
package net.sf.saxon.query;
import net.sf.saxon.functions.CallableFunction;
import net.sf.saxon.Configuration;
import net.sf.saxon.expr.*;
import net.sf.saxon.expr.instruct.UserFunction;
import net.sf.saxon.expr.parser.ExpressionVisitor;
import net.sf.saxon.functions.FunctionLibrary;
import net.sf.saxon.om.Function;
import net.sf.saxon.om.Sequence;
import net.sf.saxon.om.StandardNames;
import net.sf.saxon.om.StructuredQName;
import net.sf.saxon.trace.ExpressionPresenter;
import net.sf.saxon.trans.SymbolicName;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.type.FunctionItemType;
import net.sf.saxon.type.SpecificFunctionType;
import net.sf.saxon.value.SequenceExtent;
import java.util.HashMap;
import java.util.Iterator;
/**
* 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.
*/
public class XQueryFunctionLibrary implements FunctionLibrary, XQueryFunctionBinder {
private Configuration config;
// The functions in this library are represented using a HashMap
// The key of the hashmap is an object that encodes the QName of the function and its arity
// The value in the hashmap is an XQueryFunction
/*@NotNull*/ private HashMap functions =
new HashMap(20);
/**
* Create an XQueryFunctionLibrary
*
* @param config the Saxon configuration
*/
public XQueryFunctionLibrary(Configuration config) {
this.config = config;
}
/**
* Set the Configuration options
*
* @param config the Saxon configuration
*/
public void setConfiguration(Configuration config) {
this.config = config;
}
/**
* Get the Configuration options
*
* @return the Saxon configuration
*/
public Configuration getConfiguration() {
return config;
}
/**
* Register a user-defined XQuery function
*
* @param function the function to be registered
* @throws XPathException if there is an existing function with the same name and arity
*/
public void declareFunction(/*@NotNull*/ XQueryFunction function) throws XPathException {
SymbolicName keyObj = function.getIdentificationKey();
XQueryFunction existing = functions.get(keyObj);
if (existing == function) {
return;
}
if (existing != null) {
XPathException err = new XPathException("Duplicate definition of function " +
function.getDisplayName() +
" (see line " + existing.getLineNumber() + " in " + existing.getSystemId() + ')');
err.setErrorCode("XQST0034");
err.setIsStaticError(true);
err.setLocator(function);
throw err;
}
functions.put(keyObj, function);
}
/**
* Test whether a function with a given name and arity is available
* This supports the function-available() function in XSLT.
*
* @param functionName the qualified name of the function being called
* @return true if a function of this name and arity is available for calling
*/
public boolean isAvailable(SymbolicName functionName) {
return functions.get(functionName) != null;
}
/**
* Inner class containing information about a reference to a function whose declaration
* has not yet been encountered. The references gets fixed up later, once information
* about all user-declared functions is available.
*/
public static class UnresolvedCallable implements UserFunctionResolvable, Callable {
SymbolicName symbolicName;
UserFunction function;
public UnresolvedCallable(SymbolicName symbolicName) {
this.symbolicName = symbolicName;
}
public StructuredQName getFunctionName() {
return symbolicName.getComponentName();
}
public int getArity() {
return symbolicName.getArity();
}
//public void setFunctionItem(CallableFunctionItem fi) {
// this.functionItem = fi;
//}
/**
* Evaluate the expression
*
* @param context the dynamic evaluation context
* @param arguments the values of the arguments, supplied as Sequences
* @return the result of the evaluation, in the form of a Sequence
* @throws net.sf.saxon.trans.XPathException
* if a dynamic error occurs during the evaluation of the expression
*/
public Sequence call(XPathContext context, Sequence[] arguments) throws XPathException {
if (function == null) {
throw new XPathException("Forwards reference to XQuery function has not been resolved");
}
Sequence[] args = new Sequence[arguments.length];
for (int i = 0; i < arguments.length; i++) {
args[i] = SequenceExtent.makeSequenceExtent(arguments[i].iterate());
}
return function.call(context.newCleanContext(), args);
}
public void setFunction(UserFunction function) {
this.function = function;
//if (functionItem != null) {
// functionItem.setCallable(function.asCallable());
// functionItem.setType(function.getFunctionType());
//}
}
public UserFunction getFunction() {
return function;
}
}
/**
* Identify a (namespace-prefixed) function appearing in the expression. This
* method is called by the XQuery parser to resolve function calls found within
* the query.
* 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.
*
* @return an Expression representing the function call. This will normally be
* a FunctionCall, but it may be rewritten as some other expression.
* @throws 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.
*/
/*@Nullable*/
public Expression bind(/*@NotNull*/ SymbolicName functionName, /*@NotNull*/ Expression[] arguments, StaticContext env) throws XPathException {
XQueryFunction fd = functions.get(functionName);
if (fd != null) {
if (fd.isPrivate() && fd.getStaticContext() != env) {
throw new XPathException("Cannot call the private function " +
functionName.getComponentName().getDisplayName() + " from outside its module", "XPST0017");
}
UserFunctionCall ufc = new UserFunctionCall();
ufc.setFunctionName(fd.getFunctionName());
ufc.setArguments(arguments);
ufc.setStaticType(fd.getResultType());
UserFunction fn = fd.getUserFunction();
if (fn == null) {
// not yet compiled
fd.registerReference(ufc);
} else {
ufc.setFunction(fn);
ExpressionVisitor visitor = ExpressionVisitor.make(fd.getStaticContext());
ufc.checkFunctionCall(fn, visitor);
}
return ufc;
} else {
return null;
}
}
/**
* Get the function declaration corresponding to a given function name and arity
*
* @return the XQueryFunction if there is one, or null if not.
*/
public XQueryFunction getDeclaration(StructuredQName functionName, int staticArgs) {
SymbolicName functionKey = XQueryFunction.getIdentificationKey(
functionName, staticArgs);
return functions.get(functionKey);
}
/**
* Get the function declaration corresponding to a given function name and arity, supplied
* in the form "{uri}local/arity"
*
* @param functionKey a string in the form "{uri}local/arity" identifying the required function
* @return the XQueryFunction if there is one, or null if not.
*/
public XQueryFunction getDeclarationByKey(SymbolicName functionKey) {
return functions.get(functionKey);
}
/**
* Get an iterator over the Functions defined in this module
*
* @return an Iterator, whose items are {@link XQueryFunction} objects. It returns
* all function known to this module including those imported from elsewhere; they
* can be distinguished by their namespace.
*/
public Iterator getFunctionDefinitions() {
return functions.values().iterator();
}
/**
* Fixup all references to global functions. This method is called
* on completion of query parsing. Each XQueryFunction is required to
* bind all references to that function to the object representing the run-time
* executable code of the function.
*
* This method is for internal use.
*
* @param env the static context for the main query body.
* @throws net.sf.saxon.trans.XPathException
* if an error occurs
*/
protected void fixupGlobalFunctions(/*@NotNull*/ QueryModule env) throws XPathException {
ExpressionVisitor visitor = ExpressionVisitor.make(env);
for (XQueryFunction fn : functions.values()) {
fn.compile();
}
for (XQueryFunction fn : functions.values()) {
fn.checkReferences(visitor);
}
}
/**
* Optimize the body of all global functions. This may involve inlining functions calls
*
* @throws net.sf.saxon.trans.XPathException
* if an error occurs
*/
protected void optimizeGlobalFunctions() throws XPathException {
for (XQueryFunction fn : functions.values()) {
fn.optimize();
}
}
/**
* Output "explain" information about each declared function
*
* @param out the ExpressionPresenter that renders the output
*/
public void explainGlobalFunctions(/*@NotNull*/ ExpressionPresenter out) {
for (XQueryFunction fn : functions.values()) {
fn.explain(out);
}
}
/**
* Get the function with a given name and arity. This method is provided so that XQuery functions
* can be called directly from a Java application. Note that there is no type checking or conversion
* of arguments when this is done: the arguments must be provided in exactly the form that the function
* signature declares them.
*
* @param uri the uri of the function name
* @param localName the local part of the function name
* @param arity the number of arguments.
* @return the function identified by the URI, local name, and arity; or null if there is no such function
*/
/*@Nullable*/
public UserFunction getUserDefinedFunction(/*@NotNull*/ String uri, /*@NotNull*/ String localName, int arity) {
SymbolicName functionKey = new SymbolicName(StandardNames.XSL_FUNCTION, new StructuredQName("", uri, localName), arity);
XQueryFunction fd = functions.get(functionKey);
if (fd == null) {
return null;
}
return fd.getUserFunction();
}
/**
* 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.
*
* @return a copy of this function library. This must be an instance of the original class.
*/
/*@NotNull*/
public FunctionLibrary copy() {
XQueryFunctionLibrary qfl = new XQueryFunctionLibrary(config);
qfl.functions = new HashMap(functions);
return qfl;
}
}