package client.net.sf.saxon.ce.style;
import client.net.sf.saxon.ce.expr.Container;
import client.net.sf.saxon.ce.expr.Expression;
import client.net.sf.saxon.ce.expr.StaticContext;
import client.net.sf.saxon.ce.expr.UserFunctionCall;
import client.net.sf.saxon.ce.functions.FunctionLibrary;
import client.net.sf.saxon.ce.om.StructuredQName;
import client.net.sf.saxon.ce.trans.XPathException;
/**
* A StylesheetFunctionLibrary contains functions defined by the user in a stylesheet. This library is used at
* compile time only, as it contains references to the actual XSLFunction objects. Binding to a function in this
* library registers the function call on a fix-up list to be notified when the actual compiled function becomes
* available.
*/
public class StylesheetFunctionLibrary implements FunctionLibrary {
private PrincipalStylesheetModule stylesheet;
private boolean overriding;
/**
* Create a FunctionLibrary that provides access to stylesheet functions
* @param sheet The XSLStylesheet element of the principal stylesheet module
* @param overriding set to true if this library is to contain functions specifying override="yes",
* or to false if it is to contain functions specifying override="no". (XSLT uses two instances
* of this class, one for overriding functions and one for non-overriding functions.)
*/
public StylesheetFunctionLibrary(PrincipalStylesheetModule sheet, boolean overriding) {
this.stylesheet = sheet;
this.overriding = overriding;
}
/**
* Ask whether the functions in this library are "overriding" functions, that is, defined with
* xsl:function override="yes".
* @return true if these are overriding functions, false otherwise
*/
public boolean isOverriding() {
return overriding;
}
/**
* Test whether a function with a given name and arity is available; if so, return its signature.
* This supports the function-available() function in XSLT; it is also used to support
* higher-order functions introduced in XQuery 1.1.
*
* <p>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.</p>
* @param functionName the qualified name of the function being called
* @param arity 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.
* @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; or a zero-length
* array if the function exists but the signature is not known; or null if the function does not exist
*/
public boolean hasFunctionSignature(StructuredQName functionName, int arity) {
return stylesheet.getFunction(functionName, arity) != null;
}
/**
* Bind a 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 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.
* @param env
* @param container
* @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 client.net.sf.saxon.ce.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; or if this function library "owns" the namespace containing
* the function call, but no function was found.
*/
public Expression bind(StructuredQName functionName, Expression[] staticArgs, StaticContext env, Container container)
throws XPathException {
XSLFunction fn = stylesheet.getFunction(functionName, staticArgs.length);
if (fn==null) {
return null;
}
if (fn.isOverriding() != overriding) {
return null;
}
UserFunctionCall fc = new UserFunctionCall();
fn.registerReference(fc);
fc.setFunctionName(functionName);
fc.setArguments(staticArgs);
fc.setContainer(container);
return fc;
}
}
// 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.