LogJobFactory implements AsynchronousSpanSink.JobFactory { public static LogJobFactory withWriter(final Writer writer) { if (writer == null) throw new NullPointerException("Writer must not be null"); return withWriterProvider(new WriterProvider() { @Override public Writer getWriter() throws IOException { return writer; } }); } private  LogJobFactory(WriterProvider writerProvider); static LogJobFactory withWriter(final Writer writer); static LogJobFactory withFile(final String file); @Override Runnable createJob(SpanData data);  }
@Test public void testCreateWithWriter() throws Exception { LogJobFactory.withWriter(new StringWriter()); }
@Test(expected = NullPointerException.class) public void testCreateWithNullWriter() throws Exception { LogJobFactory.withWriter(null); }