refactored MergerPipeWithTargetPort

src/test/java/teetime/stage/basic/merger/MergerPipeWithTargetPort.java

 package teetime.stage.basic.merger;
 
-import teetime.framework.AbstractPipe;
 import teetime.framework.AbstractInputPort;
+import teetime.framework.AbstractPipe;
 import teetime.framework.signal.ISignal;
 
 final class MergerPipeWithTargetPort<T> extends AbstractPipe {
@@ -28,6 +28,12 @@ final class MergerPipeWithTargetPort<T> extends AbstractPipe {
 		return false;
 	}
 
+	@SuppressWarnings("unchecked")
+	@Override
+	public AbstractInputPort<T> getTargetPort() {
+		return (AbstractInputPort<T>) super.getTargetPort();
+	}
+
 	@Override
 	public int size() {
 		// TODO Auto-generated method stub

src/test/java/teetime/stage/basic/merger/MergerSignalTest.java

@@ -33,17 +33,16 @@ public class MergerSignalTest {
 	private AbstractInputPort<Integer> secondPort;
 	private MergerTestingPipe testPipe;
 
-	@SuppressWarnings("unchecked")
 	public void beforeSignalTesting() {
 		merger = new Merger<Integer>();
 
 		AbstractInputPort<Integer> mergerInputPort = merger.getDynamicInputPort();
 
 		MergerPipeWithTargetPort<Integer> pipe0 = new MergerPipeWithTargetPort<Integer>(mergerInputPort);
-		firstPort = (AbstractInputPort<Integer>) pipe0.getTargetPort();
+		firstPort = pipe0.getTargetPort();
 
 		MergerPipeWithTargetPort<Integer> pipe1 = new MergerPipeWithTargetPort<Integer>(mergerInputPort);
-		secondPort = (AbstractInputPort<Integer>) pipe1.getTargetPort();
+		secondPort = pipe1.getTargetPort();
 
 		testPipe = new MergerTestingPipe(merger.getOutputPort());
 	}