Updating sample application

sample/src/main/AndroidManifest.xml

@@ -3,6 +3,7 @@
           xmlns:android="http://schemas.android.com/apk/res/android">
 
     <application
+        android:name=".SampleApplication"
         android:allowBackup="true"
         android:icon="@mipmap/ic_launcher"
         android:label="@string/app_name"

sample/src/main/java/com/techyourchance/threadposters/SampleDataRetriever.java → sample/src/main/java/com/techyourchance/threadposters/FakeDataRetriever.java

@@ -2,7 +2,7 @@
 
 import android.support.annotation.WorkerThread;
 
-public class SampleDataRetriever {
+public class FakeDataRetriever {
 
     @WorkerThread
     public String getData() {

sample/src/main/java/com/techyourchance/threadposters/FetchDataUseCase.java

@@ -0,0 +1,71 @@
+package com.techyourchance.threadposters;
+
+import android.support.annotation.UiThread;
+import android.support.annotation.WorkerThread;
+
+import com.techyourchance.threadposter.UiThreadPoster;
+import com.techyourchance.threadposter.BackgroundThreadPoster;
+
+import java.util.Collections;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+
+public class FetchDataUseCase {
+
+    public interface Listener {
+        void onDataFetched(String data);
+    }
+
+    private final FakeDataRetriever mFakeDataRetriever;
+    private final BackgroundThreadPoster mBackgroundThreadPoster;
+    private final UiThreadPoster mUiThreadPoster;
+
+    private final Set<Listener> mListeners = Collections.newSetFromMap(
+            new ConcurrentHashMap<Listener, Boolean>());
+
+    public FetchDataUseCase(FakeDataRetriever fakeDataRetriever,
+                            BackgroundThreadPoster backgroundThreadPoster,
+                            UiThreadPoster uiThreadPoster) {
+        mFakeDataRetriever = fakeDataRetriever;
+        mBackgroundThreadPoster = backgroundThreadPoster;
+        mUiThreadPoster = uiThreadPoster;
+    }
+
+    public void registerListener(Listener listener) {
+        mListeners.add(listener);
+    }
+
+    public void unregisterListener(Listener listener) {
+        mListeners.remove(listener);
+    }
+
+    public void fetchData() {
+        // offload work to background thread
+        mBackgroundThreadPoster.post(new Runnable() {
+            @Override
+            public void run() {
+                fetchDataSync();
+            }
+        });
+    }
+
+    @WorkerThread
+    private void fetchDataSync() {
+        final String data = mFakeDataRetriever.getData();
+        // notify listeners on UI thread
+        mUiThreadPoster.post(new Runnable() {
+            @Override
+            public void run() {
+                notifySuccess(data);
+            }
+        });
+    }
+
+    @UiThread
+    private void notifySuccess(String data) {
+        for (Listener listener : mListeners) {
+            listener.onDataFetched(data);
+        }
+    }
+
+}

sample/src/main/java/com/techyourchance/threadposters/SampleActivity.java

@@ -7,68 +7,68 @@
 import android.widget.ProgressBar;
 import android.widget.TextView;
 
-import com.techyourchance.threadposter.UiThreadPoster;
-import com.techyourchance.threadposter.BackgroundThreadPoster;
+public class SampleActivity extends AppCompatActivity implements FetchDataUseCase.Listener {
 
-public class SampleActivity extends AppCompatActivity implements SampleWorker.SampleWorkerListener {
-
-    private Button mBtnStart;
+    private Button mBtnFetchData;
     private ProgressBar mProgressWorking;
-    private TextView mTxtDone;
-
-    /*
-    IMPORTANT:
-    Both BackgroundThreadPoster and UiThreadPoster should be global objects. Can be easily
-    achieved using dependency injection framework that supports global objects ("singletons")
-     */
-    private final BackgroundThreadPoster mBackgroundThreadPoster = new BackgroundThreadPoster();
-    private final UiThreadPoster mUiThreadPoster = new UiThreadPoster();
-
-    private final SampleDataRetriever mSampleDataRetriever = new SampleDataRetriever();
-
+    private TextView mTxtData;
 
-    private SampleWorker mSampleWorker;
+    private FetchDataUseCase mFetchDataUseCase;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_sample);
 
-        mBtnStart = (Button) findViewById(R.id.btn_start);
+        mFetchDataUseCase = ((SampleApplication)getApplication()).getFetchDataUseCase();
+
+        mBtnFetchData = (Button) findViewById(R.id.btn_fetch_data);
         mProgressWorking = (ProgressBar) findViewById(R.id.progress_working);
-        mTxtDone = (TextView) findViewById(R.id.txt_done);
+        mTxtData = (TextView) findViewById(R.id.txt_data);
 
-        mBtnStart.setOnClickListener(new View.OnClickListener() {
+        mBtnFetchData.setOnClickListener(new View.OnClickListener() {
             @Override
             public void onClick(View v) {
-                doWork();
+                fetchData();
             }
         });
 
-        mSampleWorker = new SampleWorker(mSampleDataRetriever, mBackgroundThreadPoster, mUiThreadPoster);
     }
 
     @Override
     protected void onStart() {
         super.onStart();
-        mSampleWorker.registerListener(this);
+        mFetchDataUseCase.registerListener(this);
     }
 
     @Override
     protected void onStop() {
         super.onStop();
-        mSampleWorker.unregisterListener(this);
+        mFetchDataUseCase.unregisterListener(this);
     }
 
-    private void doWork() {
-        mBtnStart.setVisibility(View.GONE);
-        mProgressWorking.setVisibility(View.VISIBLE);
-        mSampleWorker.doWork();
+    private void fetchData() {
+        mBtnFetchData.setVisibility(View.GONE);
+        showProgressIndication();
+        mFetchDataUseCase.fetchData();
     }
 
     @Override
-    public void onWorkDone(String data) {
+    public void onDataFetched(String data) {
+        hideProgressIndication();
+        showData(data);
+    }
+
+    private void showData(String data) {
+        mTxtData.setText(data);
+        mTxtData.setVisibility(View.VISIBLE);
+    }
+
+    private void hideProgressIndication() {
         mProgressWorking.setVisibility(View.GONE);
-        mTxtDone.setVisibility(View.VISIBLE);
+    }
+
+    private void showProgressIndication() {
+        mProgressWorking.setVisibility(View.VISIBLE);
     }
 }

sample/src/main/java/com/techyourchance/threadposters/SampleApplication.java

@@ -0,0 +1,24 @@
+package com.techyourchance.threadposters;
+
+import android.app.Application;
+
+import com.techyourchance.threadposter.BackgroundThreadPoster;
+import com.techyourchance.threadposter.UiThreadPoster;
+
+public class SampleApplication extends Application {
+
+    /*
+      IMPORTANT:
+      Both BackgroundThreadPoster and UiThreadPoster should be global objects (single instance).
+     */
+    private final BackgroundThreadPoster mBackgroundThreadPoster = new BackgroundThreadPoster();
+    private final UiThreadPoster mUiThreadPoster = new UiThreadPoster();
+
+    private final FakeDataRetriever mFakeDataRetriever = new FakeDataRetriever();
+    private final FetchDataUseCase mFetchDataUseCase =
+            new FetchDataUseCase(mFakeDataRetriever, mBackgroundThreadPoster, mUiThreadPoster);
+
+    public FetchDataUseCase getFetchDataUseCase() {
+        return mFetchDataUseCase;
+    }
+}

sample/src/main/res/layout/activity_sample.xml

@@ -7,12 +7,11 @@
     android:padding="20dp"
     tools:context="com.techyourchance.threadposters.SampleActivity">
 
-
     <Button
-        android:id="@+id/btn_start"
+        android:id="@+id/btn_fetch_data"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
-        android:text="Start!"
+        android:text="Fetch data!"
         android:layout_centerInParent="true"/>
 
     <ProgressBar
@@ -23,10 +22,9 @@
         android:visibility="gone"/>
 
     <TextView
-        android:id="@+id/txt_done"
+        android:id="@+id/txt_data"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
-        android:text="Done!"
         android:layout_centerInParent="true"
         android:visibility="gone"/>
 

sample/src/test/java/com/techyourchance/threadposters/SampleWorkerTest.java → sample/src/test/java/com/techyourchance/threadposters/FetchDataUseCaseTest.java

@@ -13,38 +13,38 @@
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
-public class SampleWorkerTest {
+public class FetchDataUseCaseTest {
 
     private static final String TEST_DATA = "TEST_DATA";
 
     private ThreadPostersTestController mThreadPostersTestController = new ThreadPostersTestController();
 
-    private SampleDataRetriever mSampleDataRetrieverMock;
-    private SampleWorker.SampleWorkerListener mListener1;
-    private SampleWorker.SampleWorkerListener mListener2;
+    private FakeDataRetriever mFakeDataRetrieverMock;
+    private FetchDataUseCase.Listener mListener1;
+    private FetchDataUseCase.Listener mListener2;
 
-    private SampleWorker SUT;
+    private FetchDataUseCase SUT;
 
     @Before
     public void setup() throws Exception {
-        mSampleDataRetrieverMock = mock(SampleDataRetriever.class);
+        mFakeDataRetrieverMock = mock(FakeDataRetriever.class);
 
-        when(mSampleDataRetrieverMock.getData()).thenReturn(TEST_DATA);
+        when(mFakeDataRetrieverMock.getData()).thenReturn(TEST_DATA);
 
-        SUT = new SampleWorker(
-                mSampleDataRetrieverMock,
+        SUT = new FetchDataUseCase(
+                mFakeDataRetrieverMock,
                 mThreadPostersTestController.getBackgroundThreadPosterTestDouble(),
                 mThreadPostersTestController.getUiThreadPosterTestDouble());
 
-        mListener1 = mock(SampleWorker.SampleWorkerListener.class);
-        mListener2 = mock(SampleWorker.SampleWorkerListener.class);
+        mListener1 = mock(FetchDataUseCase.Listener.class);
+        mListener2 = mock(FetchDataUseCase.Listener.class);
     }
 
     @Test
     public void doWork_noListeners_completesWithoutErrors() throws Exception {
         // Arrange
         // Act
-        SUT.doWork();
+        SUT.fetchData();
         // Assert
         assertThat(true, is(true));
     }
@@ -56,15 +56,15 @@ public void doWork_multipleListeners_notifiedWithCorrectData() throws Exception
         SUT.registerListener(mListener2);
         ArgumentCaptor<String> ac = ArgumentCaptor.forClass(String.class);
         // Act
-        SUT.doWork();
+        SUT.fetchData();
         // Assert
 
         // needs to be called before assertions in order for all threads to complete and
         // all side effects to be present
         mThreadPostersTestController.join();
 
-        verify(mListener1, times(1)).onWorkDone(ac.capture());
-        verify(mListener2, times(1)).onWorkDone(ac.capture());
+        verify(mListener1, times(1)).onDataFetched(ac.capture());
+        verify(mListener2, times(1)).onDataFetched(ac.capture());
         List<String> dataList = ac.getAllValues();
         assertThat(dataList.get(0), is(TEST_DATA));
         assertThat(dataList.get(1), is(TEST_DATA));