added iterator sample

iterator/pom.xml

@@ -0,0 +1,23 @@
+<?xml version="1.0"?>
+<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>com.iluwatar</groupId>
+    <artifactId>java-design-patterns</artifactId>
+    <version>1.0-SNAPSHOT</version>
+  </parent>
+  <groupId>com.iluwatar</groupId>
+  <artifactId>iterator</artifactId>
+  <version>1.0-SNAPSHOT</version>
+  <name>iterator</name>
+  <url>http://maven.apache.org</url>
+  <dependencies>
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <version>3.8.1</version>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+</project>

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

@@ -0,0 +1,35 @@
+package com.iluwatar;
+
+public class App 
+{
+    public static void main( String[] args )
+    {
+    	TreasureChest chest = new TreasureChest();
+    	
+    	ItemIterator ringIterator = chest.Iterator(ItemType.RING);
+    	while (ringIterator.hasNext()) {
+    		System.out.println(ringIterator.next());
+    	}
+    	
+    	System.out.println("----------");
+    	
+    	ItemIterator potionIterator = chest.Iterator(ItemType.POTION);
+    	while (potionIterator.hasNext()) {
+    		System.out.println(potionIterator.next());
+    	}
+    	
+    	System.out.println("----------");
+    	
+    	ItemIterator weaponIterator = chest.Iterator(ItemType.WEAPON);
+    	while (weaponIterator.hasNext()) {
+    		System.out.println(weaponIterator.next());
+    	}
+    	
+    	System.out.println("----------");
+    	
+    	ItemIterator it = chest.Iterator(ItemType.ANY);
+    	while (it.hasNext()) {
+    		System.out.println(it.next());
+    	}
+    }
+}

iterator/src/main/java/com/iluwatar/Item.java

@@ -0,0 +1,25 @@
+package com.iluwatar;
+
+public class Item {
+
+	private ItemType type;
+	private String name;
+
+	public Item(ItemType type, String name) {
+		this.setType(type);
+		this.name = name;
+	}
+	
+	@Override
+	public String toString() {
+		return name;
+	}
+
+	public ItemType getType() {
+		return type;
+	}
+
+	public void setType(ItemType type) {
+		this.type = type;
+	}
+}

iterator/src/main/java/com/iluwatar/ItemIterator.java

@@ -0,0 +1,8 @@
+package com.iluwatar;
+
+public interface ItemIterator {
+
+	boolean hasNext();
+	
+	Item next();
+}

iterator/src/main/java/com/iluwatar/ItemType.java

@@ -0,0 +1,10 @@
+package com.iluwatar;
+
+public enum ItemType {
+
+	ANY,
+	WEAPON,
+	RING,
+	POTION
+	
+}

iterator/src/main/java/com/iluwatar/TreasureChest.java

@@ -0,0 +1,34 @@
+package com.iluwatar;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class TreasureChest {
+
+	private List<Item> items;
+	
+	public TreasureChest() {
+		items = new ArrayList<>();
+		items.add(new Item(ItemType.POTION, "Potion of courage"));
+		items.add(new Item(ItemType.RING, "Ring of shadows"));
+		items.add(new Item(ItemType.POTION, "Potion of wisdom"));
+		items.add(new Item(ItemType.POTION, "Potion of blood"));
+		items.add(new Item(ItemType.WEAPON, "Sword of silver +1"));
+		items.add(new Item(ItemType.POTION, "Potion of rust"));
+		items.add(new Item(ItemType.POTION, "Potion of healing"));
+		items.add(new Item(ItemType.RING, "Ring of armor"));
+		items.add(new Item(ItemType.WEAPON, "Steel halberd"));
+		items.add(new Item(ItemType.WEAPON, "Dagger of poison"));
+	}
+	
+	ItemIterator Iterator(ItemType type) {
+		return new TreasureChestItemIterator(this, type);
+	}
+
+	public List<Item> getItems() {
+		ArrayList<Item> list = new ArrayList<>();
+		list.addAll(items);
+		return list;
+	}
+	
+}

iterator/src/main/java/com/iluwatar/TreasureChestItemIterator.java

@@ -0,0 +1,48 @@
+package com.iluwatar;
+
+import java.util.List;
+
+public class TreasureChestItemIterator implements ItemIterator {
+
+	private TreasureChest chest;
+	private int idx;
+	private ItemType type;
+
+	public TreasureChestItemIterator(TreasureChest chest, ItemType type) {
+		this.chest = chest;
+		this.type = type;
+		this.idx = -1;
+	}
+	
+	@Override
+	public boolean hasNext() {
+		return findNextIdx() != -1;
+	}
+
+	@Override
+	public Item next() {
+		idx = findNextIdx();
+		if (idx != -1) {
+			return chest.getItems().get(idx);
+		}
+		return null;
+	}
+	
+	private int findNextIdx() {
+		
+		List<Item> items = chest.getItems();
+		boolean found = false;
+		int tempIdx = idx;
+		while (!found) {
+			tempIdx++;
+			if (tempIdx >= items.size()) {
+				tempIdx = -1;
+				break;
+			}
+			if (type.equals(ItemType.ANY) || items.get(tempIdx).getType().equals(type)) {
+				break;
+			}
+		}
+		return tempIdx;
+	}
+}

pom.xml

@@ -33,6 +33,7 @@
     <module>chain</module>
     <module>command</module>
     <module>interpreter</module>
+    <module>iterator</module>
   </modules>
   
 <build>