Agera-Repositories

In Hello World By Agera project, we learned about Observable, Updatable, Supplier and Receiver.

The most important concept in Agera is the Repository. Repositories receive, supply, and store data and emit updates. The interfaces Observable, Supplier and Receiver are combined into two types of repositories:

In our hello world code, you could replace

implements Observable, Supplier<String>, Receiver<String>

with

 implements MutableRepository<String>

but Agera provides a Repository factory, so remove the MyDataSupplier class altogether and replace

  MyDataSupplier myDataSupplier = new MyDataSupplier();

with

 MutableRepository<String> mStringRepo = Repositories.mutableRepository("Initial value by Agera with Repository");

mutableRepository() creates a repository similar to our previous implementation, but that is thread-safe and has a more sophisticated update dispatcher, so let's use that from now on.

Also, remove the updatables (with removeUpdatable()) when you know you're done with them. In our example this is not needed but it is a good practice: it avoids potential leaks and prevents updating destroyed views. The class is now much shorter:

 public class JavaMainActivity extends AppCompatActivity {
     //    MyDataSupplier myDataSupplier = new MyDataSupplier();
     //    Updatable updatable;
     private MutableRepository<String> mStringRepo;
     private Updatable mLoggerUpdatable;


     @Override
     protected void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);

        mStringRepo = Repositories.mutableRepository("Initial value by Agera with Repository");

       final TextView textView = findViewById(R.id.textView);

          // Create an Updatable
          //        updatable = new Updatable() {
          //            @Override
          //            public void update() {
          //                Log.d("AGERA", myDataSupplier.get());
          //                textView.setText(myDataSupplier.get());
          //            }
          //        };
          //        myDataSupplier.addUpdatable(updatable);

          //        myDataSupplier.accept("Hello Agera!");


          // Create an Updatable by Respository
      mLoggerUpdatable = () -> {
          Log.d("AGERA", mStringRepo.get());
          textView.setText(mStringRepo.get());
      };
     }

      @Override
      protected void onStart() {
          super.onStart();
          mStringRepo.addUpdatable(mLoggerUpdatable);

          // Change the repository's value
          mStringRepo.accept("Hello World by Agera with Repository");
      }

    @Override
     protected void onStop() {
        mStringRepo.removeUpdatable(mLoggerUpdatable);
       super.onStop();
     }
 }

In summary:

• Agera uses very simple interfaces you should be aware of: Observable, Updatable, Supplier and Receiver. These are combined in the Repository and MutableRepository interfaces.
• Agera provides a factory of implementations of these simple Repositories: Repositories.mutableRepository(T)and Repositories.repository(T) for immutable repositories.

Next Step

Lets Learn Complex Repository Here

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  License

  Copyright 2017 Ankit Kumar
  
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at
  
     http://www.apache.org/licenses/LICENSE-2.0
  
  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.