在Java中模拟链式调用的最佳解决方案

Question

I have the following code:

handler = NodeHandler.getINodeHandler(localZone).getITspPlatformHandler().getITspProcessorManagementHandler();

I mocked this out this way:

mockStatic(NodeHandler.class);
INodeHandler iNodeHandler = mock(INodeHandler.class,Mockito.RETURNS_DEEP_STUBS);
when(NodeHandler.getINodeHandler(localZone)).thenReturn(iNodeHandler);
ITspProcessorManagementHandler iTspProcessorManagementHandler =mock(ITspProcessorManagementHandler.class,Mockito.RETURNS_DEEP_STUBS);
when(iNodeHandler.getITspPlatformHandler().getITspProcessorManagementHandler()).thenReturn(iTspProcessorManagementHandler);

After a few row of code an another chained method call comes:

ITspTrafficProcessor processor = NodeHandler.getINodeHandler(localZone, localUI).getITspPlatformHandler().getITspProcessorManagementHandler()
                .getITspProcessorHandler(procs[i]).getITspTrafficProcessorHandler(0).getAttributes();

And i mocked this out this way:

when(NodeHandler.getINodeHandler(localZone,UI.CORBA)).thenReturn(iNodeHandler);
when(iNodeHandler.getITspPlatformHandler().getITspProcessorManagementHandler()(+1+).getITspProcessorHandler(anyString())
            .getITspTrafficProcessorHandler(anyInt()).getAttributes()).thenReturn(null);

So my question is that, i can not find a better solution than this, because the problem is if i tell the mockito to return null to the handler instead of iTspProcessorManagementHandler then i get a nullpointer exception at (+1+), but if i do the following changes to my code:

INodeHandler iNodeHandler = mock(INodeHandler.class,Mockito.RETURNS_MOCKS);

Than mockito mocks out every method call, and my when-thenReturn statements does not returns what i want for example null. So any advice to do a better solution????

Answer 1

Messy mocking like that is an indication that you could improve abstraction. I'd consider encapsulating that particular logic in a helper interface/class, or to inject the expected type returned by the "trainwreck" to the method/class.