added Property pattern

property/src/main/java/com/iluwatar/App.java

@@ -0,0 +1,49 @@
+package com.iluwatar;
+
+import com.iluwatar.Character.Type;
+
+/**
+ * Example of Character instantiation using Property pattern (as concept also known like Prototype inheritance).
+ * In prototype inheritance instead of classes, as opposite to Java class inheritance,
+ * objects are used to create another objects and object hierarchies.
+ * Hierarchies are created using prototype chain through delegation: every object has link to parent object.
+ * Any base (parent) object can be amended at runtime (by adding or removal of some property), and all child objects will be affected as result.
+ */
+public class App {
+
+	public static void main(String[] args) {
+		/* set up */
+		Prototype charProto = new Character();
+		charProto.set(Stats.STRENGTH, 10);
+		charProto.set(Stats.AGILITY, 10);
+		charProto.set(Stats.ARMOR, 10);
+		charProto.set(Stats.ATTACK_POWER, 10);
+
+		Character mageProto = new Character(Type.MAGE, charProto);
+		mageProto.set(Stats.INTELLECT, 15);
+		mageProto.set(Stats.SPIRIT, 10);
+
+		Character warProto = new Character(Type.WARRIOR, charProto);
+		warProto.set(Stats.RAGE, 15);
+		warProto.set(Stats.ARMOR, 15); // boost default armor for warrior
+
+		Character rogueProto = new Character(Type.ROGUE, charProto);
+		rogueProto.set(Stats.ENERGY, 15);
+		rogueProto.set(Stats.AGILITY, 15); // boost default agility for rogue
+
+		/* usage */
+		Character mag = new Character("Player_1", mageProto);
+		mag.set(Stats.ARMOR, 8);
+		System.out.println(mag);
+
+		Character warrior = new Character("Player_2", warProto);
+		System.out.println(warrior);
+
+		Character rogue = new Character("Player_3", rogueProto);
+		System.out.println(rogue);
+
+		Character rogueDouble = new Character("Player_4", rogue);
+		rogueDouble.set(Stats.ATTACK_POWER, 12);
+		System.out.println(rogueDouble);
+	}
+}

property/src/main/java/com/iluwatar/Character.java

@@ -0,0 +1,117 @@
+package com.iluwatar;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Represents Character in game and his abilities (base stats).
+ */
+public class Character implements Prototype {
+
+	public enum Type {
+		WARRIOR, MAGE, ROGUE
+	}
+
+	private final Prototype prototype;
+	private final Map<Stats, Integer> properties = new HashMap<>();
+
+	private String name;
+	private Type type;
+
+	public Character() {
+		this.prototype = new Prototype() { // Null-value object
+			@Override
+			public Integer get(Stats stat) {
+				return null;
+			}
+			@Override
+			public boolean has(Stats stat) {
+				return false;
+			}
+			@Override
+			public void set(Stats stat, Integer val) {
+			}
+			@Override
+			public void remove(Stats stat) {
+			}}
+		;
+	}
+
+	public Character(Type type, Prototype prototype) {
+		this.type = type;
+		this.prototype = prototype;
+	}
+
+	public Character(String name, Character prototype) {
+		this.name = name;
+		this.type = prototype.type;
+		this.prototype = prototype;
+	}
+
+	public String name() {
+		return name;
+	}
+
+	public Type type() {
+		return type;
+	}
+
+	@Override
+	public Integer get(Stats stat) {
+		boolean containsValue = properties.containsKey(stat);
+		if (containsValue) {
+			return properties.get(stat);
+		} else {
+			return prototype.get(stat);
+		}
+	}
+
+	@Override
+	public boolean has(Stats stat) {
+		return get(stat) != null;
+	}
+
+	@Override
+	public void set(Stats stat, Integer val) {
+		properties.put(stat, val);
+	}
+
+	@Override
+	public void remove(Stats stat) {
+		properties.put(stat, null);
+	}
+
+	@Override
+	public String toString() {
+		StringBuilder builder = new StringBuilder();
+		if (name != null) {
+			builder
+				.append("Player: ")
+				.append(name)
+				.append("\n");
+		}
+
+		if (type != null) {
+			builder
+				.append("Character type: ")
+				.append(type.name())
+				.append("\n");
+		}
+
+		builder.append("Stats:\n");
+		for (Stats stat : Stats.values()) {
+			Integer value = this.get(stat);
+			if (value == null) {
+				continue;
+			}
+			builder
+				.append(" - ")
+				.append(stat.name())
+				.append(":")
+				.append(value)
+				.append("\n");
+		}
+		return builder.toString();
+	}
+
+}

property/src/main/java/com/iluwatar/Prototype.java

@@ -0,0 +1,12 @@
+package com.iluwatar;
+
+/**
+ * Interface for prototype inheritance
+ */
+public interface Prototype {
+
+	public Integer get(Stats stat);
+	public boolean has(Stats stat);
+	public void set(Stats stat, Integer val);
+	public void remove(Stats stat);
+}

property/src/main/java/com/iluwatar/Stats.java

@@ -0,0 +1,9 @@
+package com.iluwatar;
+
+/**
+ * All possible attributes that Character can have
+ */
+public enum Stats {
+
+	AGILITY, STRENGTH, ATTACK_POWER, ARMOR, INTELLECT, SPIRIT, ENERGY, RAGE
+}

property/src/test/java/com/iluwatar/AppTest.java

@@ -0,0 +1,12 @@
+package com.iluwatar;
+
+import org.junit.Test;
+
+public class AppTest {
+
+	@Test
+	public void test() {
+		String[] args = {};
+		App.main(args);
+	}
+}