/*
* JBoss, Home of Professional Open Source
* Copyright 2011, Red Hat, Inc., and individual contributors
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* 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 org.jboss.weld.environment.servlet.util;
import org.jboss.weld.environment.servlet.logging.WeldServletLogger;
import org.jboss.weld.bootstrap.spi.Metadata;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;
/**
* Abstract away service loader usage.
*
* @author <a href="mailto:ales.justin@jboss.org">Ales Justin</a>
*/
public class ServiceLoader {
private static final String JDK_SERVICE_LOADER = "java.util.ServiceLoader";
private static final String WELD_SERVICE_LOADER = "org.jboss.weld.util.ServiceLoader";
private static final Method loadMethod;
private static boolean weldSL = false;
private ServiceLoader() {
}
static {
ClassLoader cl = ServiceLoader.class.getClassLoader();
Class<?> clazz = null;
try {
clazz = cl.loadClass(JDK_SERVICE_LOADER);
} catch (Throwable ignored) {
}
if (clazz == null) {
try {
clazz = cl.loadClass(WELD_SERVICE_LOADER);
weldSL = true;
} catch (Throwable ignored) {
}
}
if (clazz == null) {
throw WeldServletLogger.LOG.noServiceLoaderClassAvailable();
}
try {
loadMethod = clazz.getDeclaredMethod("load", Class.class, ClassLoader.class);
} catch (Exception e) {
throw WeldServletLogger.LOG.noLoadMethodAvailableOnServiceLoader(clazz, e);
}
}
private static Iterable adapt(Iterable iterable) {
if (weldSL) {
List<Object> list = new ArrayList<Object>();
for (Object o : iterable) {
Metadata md = (Metadata) o;
list.add(md.getValue());
}
return list;
} else {
return iterable;
}
}
public static <S> Iterable<S> load(Class<S> service) {
return load(service, Thread.currentThread().getContextClassLoader());
}
public static <S> Iterable<S> load(Class<S> service, ClassLoader loader) {
if (loader == null) {
loader = service.getClassLoader();
}
try {
//noinspection unchecked
return adapt((Iterable) loadMethod.invoke(null, service, loader));
} catch (Exception e) {
throw new RuntimeException(e);
}
}
}