Added the CacheArraysFactory class.

Author: suoapvs

src/main/java/com/sorting/demonstration/arrays/CacheArraysFactory.java

@@ -0,0 +1,56 @@
+package com.sorting.demonstration.arrays;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Objects;
+
+public final class CacheArraysFactory implements ArraysFactory {
+
+    private final Map<Key, int[]> cache = new HashMap<>();
+    private final ArraysFactory arraysFactory;
+
+    public CacheArraysFactory(final ArraysFactory arraysFactory) {
+        this.arraysFactory = arraysFactory;
+    }
+
+    @Override
+    public int[] create(final int length) {
+        final Key key = new Key(length);
+        int[] array = this.cache.get(key);
+        if (isEmpty(array)) {
+            array = this.arraysFactory.create(length);
+            this.cache.put(key, array);
+        }
+        return array;
+    }
+
+    private boolean isEmpty(final int[] array) {
+        return (array == null) || (array.length == 0);
+    }
+
+    private final class Key {
+
+        private final int value;
+
+        Key(final int value) {
+            this.value = value;
+        }
+
+        @Override
+        public boolean equals(final Object object) {
+            if (this == object) {
+                return true;
+            }
+            if (object == null || getClass() != object.getClass()) {
+                return false;
+            }
+            final Key other = (Key) object;
+            return (this.value == other.value);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(this.value);
+        }
+    }
+}