7 files changed, 82 insertions, 0 deletions
diff --git a/entries/nritschel/fib-java/src/CachedFibonacciNumberFactory.java b/entries/nritschel/fib-java/src/CachedFibonacciNumberFactory.java
new file mode 100644
index 0000000..5c404e8
--- /dev/null
+++ b/entries/nritschel/fib-java/src/CachedFibonacciNumberFactory.java
@@ -0,0 +1,13 @@
+import java.util.HashMap;
+
+public class CachedFibonacciNumberFactory implements FibonacciNumberFactory {
+    private final HashMap<Integer, FibonacciNumber> cachedNumbers = new HashMap<>();
+
+    @Override
+    public FibonacciNumber getFibonacciNumber(int num) {
+        if (!cachedNumbers.containsKey(num)) {
+            cachedNumbers.put(num, new FibonacciNumber(num));
+        }
+        return cachedNumbers.get(num);
+    }
+}
diff --git a/entries/nritschel/fib-java/src/FibonacciCalculator.java b/entries/nritschel/fib-java/src/FibonacciCalculator.java
new file mode 100644
index 0000000..8806c20
--- /dev/null
+++ b/entries/nritschel/fib-java/src/FibonacciCalculator.java
@@ -0,0 +1,3 @@
+public interface FibonacciCalculator {
+    public int calculateFibonacci(FibonacciNumber fib);
+}
diff --git a/entries/nritschel/fib-java/src/FibonacciCalculatorImpl.java b/entries/nritschel/fib-java/src/FibonacciCalculatorImpl.java
new file mode 100644
index 0000000..7bb5ee9
--- /dev/null
+++ b/entries/nritschel/fib-java/src/FibonacciCalculatorImpl.java
@@ -0,0 +1,17 @@
+public class FibonacciCalculatorImpl implements FibonacciCalculator {
+    private final FibonacciNumberFactory factory;
+
+    public FibonacciCalculatorImpl(FibonacciNumberFactory factory) {
+        this.factory = factory;
+    }
+
+    @Override
+    public int calculateFibonacci(FibonacciNumber fib) {
+        if (fib.getNumber() <= 2) {
+            return 1;
+        }
+        else {
+            return factory.getFibonacciNumber(fib.getNumber() - 1).calculate(this) + factory.getFibonacciNumber(fib.getNumber() - 2).calculate(this);
+        }
+    }
+}
diff --git a/entries/nritschel/fib-java/src/FibonacciNumber.java b/entries/nritschel/fib-java/src/FibonacciNumber.java
new file mode 100644
index 0000000..fc9381f
--- /dev/null
+++ b/entries/nritschel/fib-java/src/FibonacciNumber.java
@@ -0,0 +1,19 @@
+public class FibonacciNumber {
+    private final int number;
+    private Integer result;
+
+    public FibonacciNumber(int number) {
+        this.number = number;
+    }
+
+    public int getNumber() {
+        return number;
+    }
+
+    public int calculate(FibonacciCalculator calculator) {
+        if (result == null) {
+            result = calculator.calculateFibonacci(this);
+        }
+        return result;
+    }
+}
diff --git a/entries/nritschel/fib-java/src/FibonacciNumberFactory.java b/entries/nritschel/fib-java/src/FibonacciNumberFactory.java
new file mode 100644
index 0000000..42ef6c2
--- /dev/null
+++ b/entries/nritschel/fib-java/src/FibonacciNumberFactory.java
@@ -0,0 +1,3 @@
+public interface FibonacciNumberFactory {
+    public FibonacciNumber getFibonacciNumber(int num);
+}
diff --git a/entries/nritschel/fib-java/src/Main.java b/entries/nritschel/fib-java/src/Main.java
new file mode 100644
index 0000000..8ae46f1
--- /dev/null
+++ b/entries/nritschel/fib-java/src/Main.java
@@ -0,0 +1,21 @@
+public class Main {
+    public static void main(String[] args) {
+        if (args.length < 1) {
+            System.out.println("""
+                    Please provide:
+                    1. fibonacci number to compute, and
+                    2. (optional) the calculation method (naive or cached).""");
+        }
+        else {
+            FibonacciNumberFactory factory;
+            if (args.length >= 2 && args[1].equals("naive")) {
+                factory = new NaiveFibonacciNumberFactory();
+            }
+            else {
+                factory = new CachedFibonacciNumberFactory();
+            }
+            FibonacciCalculator calculator = new FibonacciCalculatorImpl(factory);
+            System.out.println(factory.getFibonacciNumber(Integer.parseInt(args[0])).calculate(calculator));
+        }
+    }
+}
diff --git a/entries/nritschel/fib-java/src/NaiveFibonacciNumberFactory.java b/entries/nritschel/fib-java/src/NaiveFibonacciNumberFactory.java
new file mode 100644
index 0000000..5185a8b
--- /dev/null
+++ b/entries/nritschel/fib-java/src/NaiveFibonacciNumberFactory.java
@@ -0,0 +1,6 @@
+public class NaiveFibonacciNumberFactory implements FibonacciNumberFactory {
+    @Override
+    public FibonacciNumber getFibonacciNumber(int num) {
+        return new FibonacciNumber(num);
+    }
+}