Update Method pattern (#1106)

* Add update method pattern

* Add unit tests

* Add README.md

* Resolve conflict

update-method/src/main/java/com/iluwatar/updatemethod/Entity.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.updatemethod;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Abstract class for all the entity types.
+ */
+public abstract class Entity {
+
+  protected final Logger logger = LoggerFactory.getLogger(this.getClass());
+
+  protected int id;
+
+  protected int position;
+
+  public Entity(int id) {
+    this.id = id;
+    this.position = 0;
+  }
+
+  public abstract void update();
+
+  public int getPosition() {
+    return position;
+  }
+
+  public void setPosition(int position) {
+    this.position = position;
+  }
+}