package net.sf.saxon.functions;
import net.sf.saxon.expr.Expression;
import net.sf.saxon.expr.StaticContext;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.query.XQueryFunctionBinder;
import net.sf.saxon.query.XQueryFunction;
import net.sf.saxon.om.StructuredQName;
import net.sf.saxon.value.SequenceType;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
/**
* A FunctionLibraryList is a list of FunctionLibraries. It is also a FunctionLibrary in its own right.
* When required, it searches the list of FunctionLibraries to find the required function.
*/
public class FunctionLibraryList implements FunctionLibrary, XQueryFunctionBinder {
public List libraryList = new ArrayList(8);
public FunctionLibraryList() {}
/**
* Add a new FunctionLibrary to the list of FunctionLibraries in this FunctionLibraryList. Note
* that libraries are searched in the order they are added to the list.
* @param lib A function library to be added to the list of function libraries to be searched.
* @return the position of the library in the list
*/
public int addFunctionLibrary(FunctionLibrary lib) {
libraryList.add(lib);
return libraryList.size() - 1;
}
/**
* Get the n'th function library in the list
*/
public FunctionLibrary get(int n) {
return (FunctionLibrary)libraryList.get(n);
}
/**
* Test whether a system function with a given name and arity is available, and return its signature. This supports
* the function-available() function in XSLT. This method may be called either at compile time
* or at run time.
* @param functionName the name of the function
* @param arity The number of arguments. This is set to -1 in the case of the single-argument
* @return if a function of this name and arity is available for calling, then the type signature of the
* function, as an array of sequence types in which the zeroth entry represents the return type; otherwise null
*/
public SequenceType[] getFunctionSignature(StructuredQName functionName, int arity) {
for (Iterator it=libraryList.iterator(); it.hasNext();) {
FunctionLibrary lib = (FunctionLibrary)it.next();
SequenceType[] sig = lib.getFunctionSignature(functionName, arity);
if (sig != null) {
return sig;
}
}
return null;
}
/**
* 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.
* @param functionName
* @param staticArgs 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.
* @param env
* @return An object representing the extension function to be called, if one is found;
* null if no extension function was found matching the required name and arity.
* @throws net.sf.saxon.trans.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.
*/
public Expression bind(StructuredQName functionName, Expression[] staticArgs, StaticContext env)
throws XPathException {
boolean debug = env.getConfiguration().isTraceExternalFunctions();
if (debug) {
System.err.println("Looking for function " + functionName.getClarkName());
}
for (Iterator it=libraryList.iterator(); it.hasNext();) {
FunctionLibrary lib = (FunctionLibrary)it.next();
if (debug) {
System.err.println("Trying " + lib.getClass().getName());
}
Expression func = lib.bind(functionName, staticArgs, env);
if (func != null) {
return func;
}
}
if (debug) {
System.err.println("Function " + functionName.getClarkName() + " not found!");
}
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, Expression[] staticArgs) {
for (Iterator it=libraryList.iterator(); it.hasNext();) {
FunctionLibrary lib = (FunctionLibrary)it.next();
if (lib instanceof XQueryFunctionBinder) {
XQueryFunction func = ((XQueryFunctionBinder)lib).getDeclaration(functionName, staticArgs);
if (func != null) {
return func;
}
}
}
return null;
}
/**
* Get the list of contained FunctionLibraries. This method allows the caller to modify
* the library list, for example by adding a new FunctionLibrary at a chosen position,
* by removing a library from the list, or by changing the order of libraries in the list.
* Note that such changes may violate rules in the
* language specifications, or assumptions made within the product.
* @return a list whose members are of class FunctionLibrary
*/
public List getLibraryList() {
return libraryList;
}
/**
* 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.
*/
public FunctionLibrary copy() {
FunctionLibraryList fll = new FunctionLibraryList();
fll.libraryList = new ArrayList(libraryList.size());
for (int i=0; i<libraryList.size(); i++) {
fll.libraryList.add(((FunctionLibrary)libraryList.get(i)).copy());
}
return fll;
}
}
//
// The contents of this file are subject to the Mozilla Public License Version 1.0 (the "License");
// you may not use this file except in compliance with the License. You may obtain a copy of the
// License at http://www.mozilla.org/MPL/
//
// Software distributed under the License is distributed on an "AS IS" basis,
// WITHOUT WARRANTY OF ANY KIND, either express or implied.
// See the License for the specific language governing rights and limitations under the License.
//
// The Original Code is: all this file.
//
// The Initial Developer of the Original Code is Michael H. Kay.
//
// Portions created by (your name) are Copyright (C) (your legal entity). All Rights Reserved.
//
// Contributor(s): none.
//