public static <T> ResourceAllocator<T> getInstance(Class<T> clz){
		
		if(clz.equals(Resource.class)){
			return (ResourceAllocator<T>) RESOURCE_ALLOCATOR;
		}
		if(clz.equals(InputStream.class)){
			return (ResourceAllocator<T>) INPUTSTREAM_ALLOCATOR;
		}
		return null;
	}