Java tutorial
/** * Copyright 2010-2015 Axel Fontaine * <p/> * 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 * <p/> * http://www.apache.org/licenses/LICENSE-2.0 * <p/> * 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.contrastsecurity.cassandra.migration.utils; public class FeatureDetector { private ClassLoader classLoader; private Boolean slf4jAvailable; private Boolean apacheCommonsLoggingAvailable; public FeatureDetector(ClassLoader classLoader) { this.classLoader = classLoader; } public boolean isApacheCommonsLoggingAvailable() { if (apacheCommonsLoggingAvailable == null) { apacheCommonsLoggingAvailable = isPresent("org.apache.commons.logging.Log", classLoader); } return apacheCommonsLoggingAvailable; } public boolean isSlf4jAvailable() { if (slf4jAvailable == null) { slf4jAvailable = isPresent("org.slf4j.Logger", classLoader); } return slf4jAvailable; } private boolean isPresent(String className, ClassLoader classLoader) { try { classLoader.loadClass(className); return true; } catch (Throwable ex) { // Class or one of its dependencies is not present... return false; } } }