| /** |
| * Copyright 2010 Newcastle University |
| * |
| * http://research.ncl.ac.uk/smart/ |
| * |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (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.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package org.apache.oltu.oauth2.rsfilter; |
| |
| import javax.servlet.FilterConfig; |
| import javax.servlet.ServletContext; |
| import javax.servlet.ServletException; |
| |
| /** |
| * |
| * |
| * |
| */ |
| public class OAuthUtils { |
| |
| public static <T> T initiateServletContext(FilterConfig config, String key, Class<T> expectedClass) |
| throws ServletException { |
| |
| T provider = (T) config.getServletContext().getAttribute(key); |
| |
| if (provider != null) { |
| return provider; |
| } |
| |
| provider = (T) loadObject(config, key, expectedClass); |
| |
| // set the provider and validator |
| config.getServletContext().setAttribute(key, provider); |
| |
| return provider; |
| } |
| |
| public static <T> T loadObject(FilterConfig config, String classParamName, Class<T> expectedClass) |
| throws ServletException { |
| |
| T ob = null; |
| |
| String providerClassName = config.getInitParameter(classParamName); |
| if (isEmpty(providerClassName)) { |
| throw new ServletException(classParamName + " context param required"); |
| } |
| try { |
| Class<T> clazz = (Class<T>) Class.forName(providerClassName); |
| if (!expectedClass.isAssignableFrom(clazz)) { |
| throw new ServletException(classParamName + " class: " + providerClassName |
| + " must be an instance of: " + expectedClass.getName()); |
| } |
| ob = createObjectFromClassName(clazz); |
| } catch (ClassNotFoundException e) { |
| throw new ServletException(classParamName + " class " + providerClassName + " not found"); |
| } catch (Exception e) { |
| throw new ServletException("Cannot instantiate: " + providerClassName); |
| } |
| return ob; |
| } |
| |
| public static <T> T createObjectFromClassName(Class<T> clazz) throws IllegalAccessException, InstantiationException { |
| return clazz.newInstance(); |
| } |
| |
| public static boolean isEmpty(String value) { |
| return value == null || value.isEmpty(); |
| } |
| } |