Game Loop Pattern (#1083)

* Add game loop module

* Add game loop module

* Fix merge issue

* Implement game loop module

* Implement game loop module

* Implement time based game loop

* implement VariableStepGameLoop

* Implement FixedStepGameLoop

* Add UT

* Add Unit tests

* Fix checkstyle issues

* Add README.md

* Fix code review issues

* Fix code review issues

* update README.md

game-loop/src/test/java/com/iluwatar/gameloop/AppTest.java

@@ -0,0 +1,39 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.gameloop;
+
+import org.junit.Test;
+
+/**
+ * App unit test class.
+ */
+public class AppTest {
+
+  @Test
+  public void testMain() {
+    String[] args = {};
+    new App().main(args);
+  }
+
+}

game-loop/src/test/java/com/iluwatar/gameloop/FixedStepGameLoopTest.java

@@ -0,0 +1,54 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.gameloop;
+
+import org.junit.After;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * FixedStepGameLoop unit test class.
+ */
+public class FixedStepGameLoopTest {
+
+  private FixedStepGameLoop gameLoop;
+
+  @Before
+  public void setup() {
+    gameLoop = new FixedStepGameLoop();
+  }
+
+  @After
+  public void tearDown() {
+    gameLoop = null;
+  }
+
+  @Test
+  public void testUpdate() {
+    gameLoop.update();
+    Assert.assertEquals(0.01f, gameLoop.controller.getBulletPosition(), 0);
+  }
+
+}

game-loop/src/test/java/com/iluwatar/gameloop/FrameBasedGameLoopTest.java

@@ -0,0 +1,53 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.gameloop;
+
+import org.junit.After;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * FrameBasedGameLoop unit test class.
+ */
+public class FrameBasedGameLoopTest {
+
+  private FrameBasedGameLoop gameLoop;
+
+  @Before
+  public void setup() {
+    gameLoop = new FrameBasedGameLoop();
+  }
+
+  @After
+  public void tearDown() {
+    gameLoop = null;
+  }
+
+  @Test
+  public void testUpdate() {
+    gameLoop.update();
+    Assert.assertEquals(0.5f, gameLoop.controller.getBulletPosition(), 0);
+  }
+}

game-loop/src/test/java/com/iluwatar/gameloop/GameControllerTest.java

@@ -0,0 +1,56 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.gameloop;
+
+import org.junit.After;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+public class GameControllerTest {
+
+  private GameController controller;
+
+  @Before
+  public void setup() {
+    controller = new GameController();
+  }
+
+  @After
+  public void tearDown() {
+    controller = null;
+  }
+
+  @Test
+  public void testMoveBullet() {
+    controller.moveBullet(1.5f);
+    Assert.assertEquals(1.5f, controller.bullet.getPosition(), 0);
+  }
+
+  @Test
+  public void testGetBulletPosition() {
+    Assert.assertEquals(controller.bullet.getPosition(), controller.getBulletPosition(), 0);
+  }
+
+}

game-loop/src/test/java/com/iluwatar/gameloop/GameLoopTest.java

@@ -0,0 +1,71 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.gameloop;
+
+import org.junit.After;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * GameLoop unit test class.
+ */
+public class GameLoopTest {
+
+  private GameLoop gameLoop;
+
+  /**
+   * Create mock implementation of GameLoop.
+   */
+  @Before
+  public void setup() {
+    gameLoop = new GameLoop() {
+      @Override
+      protected void processGameLoop() {}
+    };
+  }
+
+  @After
+  public void tearDown() {
+    gameLoop = null;
+  }
+
+  @Test
+  public void testRun() {
+    gameLoop.run();
+    Assert.assertEquals(GameStatus.RUNNING, gameLoop.status);
+  }
+
+  @Test
+  public void testStop() {
+    gameLoop.stop();
+    Assert.assertEquals(GameStatus.STOPPED, gameLoop.status);
+  }
+
+  @Test
+  public void testIsGameRunning() {
+    Assert.assertEquals(false, gameLoop.isGameRunning());
+  }
+
+}

game-loop/src/test/java/com/iluwatar/gameloop/VariableStepGameLoopTest.java

@@ -0,0 +1,54 @@
+/*
+ * The MIT License
+ * Copyright © 2014-2019 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package com.iluwatar.gameloop;
+
+import java.lang.reflect.InvocationTargetException;
+import org.junit.After;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * VariableStepGameLoop unit test class.
+ */
+public class VariableStepGameLoopTest {
+
+  private VariableStepGameLoop gameLoop;
+
+  @Before
+  public void setup() {
+    gameLoop = new VariableStepGameLoop();
+  }
+
+  @After
+  public void tearDown() {
+    gameLoop = null;
+  }
+
+  @Test
+  public void testUpdate() {
+    gameLoop.update(20L);
+    Assert.assertEquals(0.01f, gameLoop.controller.getBulletPosition(), 0);
+  }
+}