title: How shall I use ProtocolBuffer's FieldMasks?
body: <p>We are only recently adopting ProtocolBuffers in out platform, and I've seen the introduction of the FieldMasks in v3, but we can't seem to figure out how to use them.</p>
  
  <p>We have generated our proto classes with v3 compiler, here's an example on how we intend to use them:</p>
  
  <pre><code>FieldMask fieldMask = FieldMask.newBuilder().addPaths("field1").build();
  </code></pre>
  
  <p>Now how do I apply this FieldMask to my proto generated class in order to perform a field search on it?</p>
  
  <p>I've figured out how to perform searches through FieldDescriptors, but I can't seem to find the way to relate the FieldMask with the object I want to search in.</p>
  
  <p>Any help would be appreciated.
  Thanks</p>