import org.pentaho.di.core.changed.PDIObserver; //导入依赖的package包/类
@Test
public void testAddDeleteModifyObserver() throws Exception {
  meta.deleteObserver( null );
  PDIObserver observer = mock( PDIObserver.class );
  meta.addObserver( observer );
  Object event = new Object();
  meta.notifyObservers( event );
  // Changed flag isn't set, so this won't be called
  verify( observer, never() ).update( meta, event );
  meta.setChanged( true );
  meta.notifyObservers( event );
  verify( observer, times( 1 ) ).update( any( ChangedFlagInterface.class ), anyObject() );
}
 

import org.pentaho.di.core.changed.PDIObserver; //导入依赖的package包/类
public void addObserver( PDIObserver o ) {
  changedFlag.addObserver( o );
}
 

import org.pentaho.di.core.changed.PDIObserver; //导入依赖的package包/类
public void deleteObserver( PDIObserver o ) {
  changedFlag.deleteObserver( o );
}