├── .gitignore ├── CONTRIBUTING ├── LICENSE ├── README.md ├── WORKSPACE ├── java └── reagera │ ├── BUILD │ ├── Listener.java │ ├── Reducer.java │ ├── Store.java │ └── Subscription.java └── javatests └── reagera ├── BUILD └── StoreTest.java /.gitignore: -------------------------------------------------------------------------------- 1 | .DS_Store 2 | bazel-* 3 | 4 | -------------------------------------------------------------------------------- /CONTRIBUTING: -------------------------------------------------------------------------------- 1 | Want to contribute? Great! First, read this page (including the small print at the end). 2 | 3 | ### Before you contribute 4 | Before we can use your code, you must sign the 5 | [Google Individual Contributor License Agreement] 6 | (https://cla.developers.google.com/about/google-individual) 7 | (CLA), which you can do online. 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All Rights Reserved. 3 | * 4 | * Licensed under the Apache License, Version 2.0 (the "License"); 5 | * you may not use this file except in compliance with the License. 6 | * You may obtain a copy of the License at 7 | * 8 | * http://www.apache.org/licenses/LICENSE-2.0 9 | * 10 | * Unless required by applicable law or agreed to in writing, software 11 | * distributed under the License is distributed on an "AS IS" BASIS, 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 | * See the License for the specific language governing permissions and 14 | * limitations under the License. 15 | */ 16 | 17 | package reagera; 18 | 19 | /** 20 | * Gets notified when state changes. 21 | */ 22 | public interface Listener { 23 | /** 24 | * Gets called by the {@link Store} after each state transition. 25 | */ 26 | void stateChanged(); 27 | } 28 | -------------------------------------------------------------------------------- /java/reagera/Reducer.java: -------------------------------------------------------------------------------- 1 | /** 2 | * Copyright 2016 Google Inc. All Rights Reserved. 3 | * 4 | * Licensed under the Apache License, Version 2.0 (the "License"); 5 | * you may not use this file except in compliance with the License. 6 | * You may obtain a copy of the License at 7 | * 8 | * http://www.apache.org/licenses/LICENSE-2.0 9 | * 10 | * Unless required by applicable law or agreed to in writing, software 11 | * distributed under the License is distributed on an "AS IS" BASIS, 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 | * See the License for the specific language governing permissions and 14 | * limitations under the License. 15 | */ 16 | 17 | package reagera; 18 | 19 | /** 20 | * Updates the state by handling actions. 21 | */ 22 | public interface Reducer { 23 | /** 24 | * Takes the current state, an action and returns the changed state. 25 | */ 26 | S reduce(S state, A action); 27 | } 28 | -------------------------------------------------------------------------------- /java/reagera/Store.java: -------------------------------------------------------------------------------- 1 | /** 2 | * Copyright 2016 Google Inc. All Rights Reserved. 3 | * 4 | * Licensed under the Apache License, Version 2.0 (the "License"); 5 | * you may not use this file except in compliance with the License. 6 | * You may obtain a copy of the License at 7 | * 8 | * http://www.apache.org/licenses/LICENSE-2.0 9 | * 10 | * Unless required by applicable law or agreed to in writing, software 11 | * distributed under the License is distributed on an "AS IS" BASIS, 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 | * See the License for the specific language governing permissions and 14 | * limitations under the License. 15 | */ 16 | 17 | package reagera; 18 | 19 | import java.util.Collections; 20 | import java.util.Set; 21 | import java.util.concurrent.ConcurrentHashMap; 22 | import java.util.concurrent.atomic.AtomicReference; 23 | 24 | /** 25 | * The main keeper of all state. An app should have at most one instance 26 | * of this class. {@link S} denotes the type of the state and {@link A} denotes 27 | * the type of the actions. Both {@link S} and {@link A} should be immutable. 28 | * 29 | *

Note: This class is thread safe.

30 | */ 31 | public final class Store { 32 | private AtomicReference stateRef; 33 | private final Reducer rootReducer; 34 | private final Set listeners; 35 | 36 | public Store(S initialState, Reducer rootReducer) { 37 | this.stateRef = new AtomicReference<>(initialState); 38 | this.rootReducer = rootReducer; 39 | this.listeners = Collections.newSetFromMap(new ConcurrentHashMap<>()); 40 | } 41 | 42 | /** Dispatches an action to the {@link Store} which may change the state. */ 43 | public void dispatch(A action) { 44 | S state; 45 | do { 46 | state = stateRef.get(); 47 | } while (!stateRef.compareAndSet(state, rootReducer.reduce(state, action))); 48 | listeners.forEach(Listener::stateChanged); 49 | } 50 | 51 | /** Retrieves the current state. */ 52 | public S getState() { 53 | return stateRef.get(); 54 | } 55 | 56 | /** Subscribes the {@link Listener} to state changes. */ 57 | public Subscription subscribe(Listener listener) { 58 | listeners.add(listener); 59 | return () -> listeners.remove(listener); 60 | } 61 | } 62 | -------------------------------------------------------------------------------- /java/reagera/Subscription.java: -------------------------------------------------------------------------------- 1 | /** 2 | * Copyright 2016 Google Inc. All Rights Reserved. 3 | * 4 | * Licensed under the Apache License, Version 2.0 (the "License"); 5 | * you may not use this file except in compliance with the License. 6 | * You may obtain a copy of the License at 7 | * 8 | * http://www.apache.org/licenses/LICENSE-2.0 9 | * 10 | * Unless required by applicable law or agreed to in writing, software 11 | * distributed under the License is distributed on an "AS IS" BASIS, 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 | * See the License for the specific language governing permissions and 14 | * limitations under the License. 15 | */ 16 | 17 | package reagera; 18 | 19 | /** 20 | * A handle to unsubscribe a {@link Listener}. 21 | */ 22 | public interface Subscription { 23 | void unsubscribe(); 24 | } 25 | -------------------------------------------------------------------------------- /javatests/reagera/BUILD: -------------------------------------------------------------------------------- 1 | java_test( 2 | name = 'tests', 3 | srcs = glob([ 4 | '*.java', 5 | ]), 6 | runtime_deps = [ 7 | '//external:hamcrest', 8 | ], 9 | deps = [ 10 | '//external:guava', 11 | '//external:junit', 12 | '//external:truth', 13 | "//java/reagera", 14 | ] 15 | ) 16 | -------------------------------------------------------------------------------- /javatests/reagera/StoreTest.java: -------------------------------------------------------------------------------- 1 | /** 2 | * Copyright 2016 Google Inc. All Rights Reserved. 3 | * 4 | * Licensed under the Apache License, Version 2.0 (the "License"); 5 | * you may not use this file except in compliance with the License. 6 | * You may obtain a copy of the License at 7 | * 8 | * http://www.apache.org/licenses/LICENSE-2.0 9 | * 10 | * Unless required by applicable law or agreed to in writing, software 11 | * distributed under the License is distributed on an "AS IS" BASIS, 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 | * See the License for the specific language governing permissions and 14 | * limitations under the License. 15 | */ 16 | 17 | package reagera; 18 | 19 | import org.junit.Test; 20 | import org.junit.runner.RunWith; 21 | import org.junit.runners.JUnit4; 22 | 23 | import static com.google.common.truth.Truth.assertThat; 24 | import static org.junit.Assert.fail; 25 | 26 | /** 27 | * Tests for {@link Store}. 28 | */ 29 | @RunWith(JUnit4.class) 30 | public final class StoreTest { 31 | private static final Reducer REDUCER = 32 | (state, action) -> action.equals(Action.INCREMENT) ? ++state : state; 33 | 34 | private enum Action { 35 | INCREMENT 36 | } 37 | 38 | private Store store; 39 | 40 | @Test 41 | public void dispatch() { 42 | store = new Store<>(0, REDUCER); 43 | assertThat(store.getState()).isEqualTo(0); 44 | store.dispatch(Action.INCREMENT); 45 | assertThat(store.getState()).isEqualTo(1); 46 | } 47 | 48 | @Test 49 | public void subscribe() { 50 | store = new Store<>(0, REDUCER); 51 | final boolean[] wasNotified = new boolean[1]; 52 | Listener listener = () -> { 53 | wasNotified[0] = true; 54 | }; 55 | store.subscribe(listener); 56 | store.dispatch(Action.INCREMENT); 57 | assertThat(wasNotified[0]).isTrue(); 58 | } 59 | 60 | @Test 61 | public void unsubscribe() { 62 | store = new Store<>(0, REDUCER); 63 | Listener listener = () -> { 64 | fail("was unsubscribed but got notified"); 65 | }; 66 | store.subscribe(listener).unsubscribe(); 67 | store.dispatch(Action.INCREMENT); 68 | } 69 | } 70 | --------------------------------------------------------------------------------