added iterator sample

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;
+	}
+}