Logback: the reliable, generic, fast and flexible logging framework.
Copyright (C) 1999-2015, QOS.ch. All rights reserved.
This program and the accompanying materials are dual-licensed under
either the terms of the Eclipse Public License v1.0 as published by
the Eclipse Foundation
  or (per the licensee's choosing)
under the terms of the GNU Lesser General Public License version 2.1
as published by the Free Software Foundation.
/**
 * Logback: the reliable, generic, fast and flexible logging framework.
 * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
 *
 * This program and the accompanying materials are dual-licensed under
 * either the terms of the Eclipse Public License v1.0 as published by
 * the Eclipse Foundation
 *
 *   or (per the licensee's choosing)
 *
 * under the terms of the GNU Lesser General Public License version 2.1
 * as published by the Free Software Foundation.
 */
package ch.qos.logback.classic.util;

import java.util.Iterator;
import java.util.ServiceLoader;

import ch.qos.logback.core.util.Loader;

Author:
Ceki Gülcü/**
 * @author Ceki Gülcü
 */
public class EnvUtil {

    /*
     * Used to replace the ClassLoader that the ServiceLoader uses for unit testing. We need this to mock the resources
     * the ServiceLoader attempts to load from /META-INF/services thus keeping the projects src/test/resources clean
     * (see src/test/resources/README.txt).
     */
    static ClassLoader testServiceLoaderClassLoader = null;

    static public boolean isGroovyAvailable() {
        ClassLoader classLoader = Loader.getClassLoaderOfClass(EnvUtil.class);
        try {
            Class<?> bindingClass = classLoader.loadClass("groovy.lang.Binding");
            return (bindingClass != null);
        } catch (ClassNotFoundException e) {
            return false;
        }
    }

    private static ClassLoader getServiceLoaderClassLoader() {
        return testServiceLoaderClassLoader == null ? Loader.getClassLoaderOfClass(EnvUtil.class) : testServiceLoaderClassLoader;
    }

    public static <T> T loadFromServiceLoader(Class<T> c) {
        ServiceLoader<T> loader = ServiceLoader.load(c, getServiceLoaderClassLoader());
        Iterator<T> it = loader.iterator();
        if (it.hasNext())
            return it.next();
        return null;
    }

}