impl: cll get before & after

assignment/src/main/java/appointmentplanner/customlist/CustomLinkedListImpl.java

@@ -27,19 +27,57 @@ public class CustomLinkedListImpl<T> implements CustomLinkedList<T> {
     }
   }
 
-  private CustomLinkedListNode<T> traverseFind(CustomLinkedListNode<T> currentNode, T item) {
+  private static enum ItemPosition {
+    AFTER, BEFORE, CURRENT
+  }
+
+  private CustomLinkedListNode<T> traverseFind(CustomLinkedListNode<T> currentNode, T item, ItemPosition position) {
 
     CustomLinkedListNode<T> nextNode = currentNode.getNext();
 
+    switch (position) {
+
+      case CURRENT:
+
+        if (currentNode.getItem().equals(item)) {
+          return currentNode;
+        }
+
+        break;
+
+      case AFTER:
+
+        if (nextNode == null) {
+          return null;
+        }
+
+        if (nextNode.getItem().equals(item)) {
+          return currentNode;
+        }
+
+        break;
+
+      case BEFORE:
+
+        if (nextNode == null) {
+          return null;
+        }
+
+        if (currentNode.getItem().equals(item)) {
+          return nextNode;
+        }
+
+        break;
+
+      default:
+        return null;
+    }
+
     if (nextNode == null) {
       return null;
     }
 
-    if (currentNode.getItem().equals(item)) {
-      return currentNode;
-    }
-
-    return traverseFind(nextNode, item);
+    return traverseFind(nextNode, item, position);
   }
 
   @Override
@@ -62,19 +100,19 @@ public class CustomLinkedListImpl<T> implements CustomLinkedList<T> {
 
   @Override
   public T getAfter(T reference) {
-    // TODO Auto-generated method stub
-    throw new UnsupportedOperationException("Unimplemented method 'getAfter'");
+    CustomLinkedListNode<T> node = traverseFind(head, reference, ItemPosition.AFTER);
+    return node == null ? null : node.getItem();
   }
 
   @Override
   public T getBefore(T reference) {
-    // TODO Auto-generated method stub
-    throw new UnsupportedOperationException("Unimplemented method 'getBefore'");
+    CustomLinkedListNode<T> node = traverseFind(head, reference, ItemPosition.BEFORE);
+    return node == null ? null : node.getItem();
   }
 
   @Override
   public boolean contains(T item) {
-    return traverseFind(head, item) != null ? true : false;
+    return traverseFind(head, item, ItemPosition.CURRENT) != null ? true : false;
   }
 
   private int recursiveSizeCalc(CustomLinkedListNode<T> node, int count) {