Method defineFunction

java/jakarta/el/ELProcessor.java:150–228

Registers a function in the EL context by looking up the static method in the given class. The method name may include a return type and parameter signature in the format returnType methodName(paramTypes). The function is then callable in EL expressions as prefix:function(args). @pa

(String prefix, String function, String className, String methodName)

     * @throws NoSuchMethodException   if the method cannot be found or is not a public static method
     */
    public void defineFunction(String prefix, String function, String className, String methodName)
            throws ClassNotFoundException, NoSuchMethodException {

        if (prefix == null || function == null || className == null || methodName == null) {
            throw new NullPointerException(Util.message(context, "elProcessor.defineFunctionNullParams"));
        }

        // Check the imports
        Class<?> clazz = context.getImportHandler().resolveClass(className);

        if (clazz == null) {
            clazz = Class.forName(className, true, Thread.currentThread().getContextClassLoader());
        }

        if (!Modifier.isPublic(clazz.getModifiers())) {
            throw new ClassNotFoundException(
                    Util.message(context, "elProcessor.defineFunctionInvalidClass", className));
        }

        MethodSignature sig = new MethodSignature(context, methodName, className);

        if (function.isEmpty()) {
            function = sig.getName();
        }

        // Only returns public methods. Module access is checked below.
        Method[] methods = clazz.getMethods();

        for (Method method : methods) {
            if (!Modifier.isStatic(method.getModifiers())) {
                continue;
            }
            if (!Util.canAccess(null, method)) {
                continue;
            }
            if (method.getName().equals(sig.getName())) {
                if (sig.getParamTypeNames() == null) {
                    // Only a name provided, no signature so map the first
                    // method declared
                    manager.mapFunction(prefix, function, method);
                    return;
                }
                if (sig.getParamTypeNames().length != method.getParameterTypes().length) {
                    continue;
                }
                if (sig.getParamTypeNames().length == 0) {
                    manager.mapFunction(prefix, function, method);
                    return;
                } else {
                    Class<?>[] types = method.getParameterTypes();
                    String[] typeNames = sig.getParamTypeNames();
                    boolean match = true;
                    for (int i = 0; i < types.length; i++) {
                        if (i == types.length - 1 && method.isVarArgs()) {
                            String typeName = typeNames[i];
                            if (typeName.endsWith("...")) {
                                typeName = typeName.substring(0, typeName.length() - 3);
                                if (!typeName.equals(types[i].getName())) {