package com.ctrip.framework.foundation.internals;
import java.util.Iterator;
import java.util.ServiceLoader;
public class ServiceBootstrap {
public static <S> S loadFirst(Class<S> clazz) {
Iterator<S> iterator = loadAll(clazz);
if (!iterator.hasNext()) {
throw new IllegalStateException(String.format(
"No implementation defined in /META-INF/services/%s, please check whether the file exists and has the right implementation class!",
clazz.getName()));
}
return iterator.next();
}
private static <S> Iterator<S> loadAll(Class<S> clazz) {
ServiceLoader<S> loader = ServiceLoader.load(clazz);
return loader.iterator();
}
}