Java tutorial
/* * Copyright 2008 Pavel Syrtsov * * Licensed 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 com.sf.ddao.chain; import org.apache.commons.chain.Context; import org.apache.commons.chain.impl.ContextBase; import java.util.concurrent.Callable; /** * Date: Oct 27, 2009 * Time: 4:29:13 PM */ public class CtxHelper { public static <T> T get(Context ctx, Class<T> clazz) { //noinspection unchecked return (T) ctx.get(clazz.toString()); } public static <T> T get(Context ctx, Class<T> clazz, Callable<T> callback) throws Exception { //noinspection unchecked T res = (T) ctx.get(clazz.toString()); if (res == null) { res = callback.call(); put(ctx, clazz, res); } return res; } public static <T> T put(Context ctx, Class<T> clazz, T value) { //noinspection unchecked return (T) ctx.put(clazz.toString(), value); } public static Context context(Object... argv) { Context res = new ContextBase(); String key = null; for (Object o : argv) { if (key == null) { key = (String) o; } else { //noinspection unchecked res.put(key, o); key = null; } } return res; } public static <T> T remove(Context ctx, Class<T> clazz) { //noinspection unchecked return (T) ctx.remove(clazz.toString()); } }