Add generic methods that allows to get next or previous elements in g…

…iven array.

src/main/java/world/bentobox/challenges/utils/Utils.java

@@ -95,4 +95,60 @@ public static String getGameMode(World world)
 			map(gameModeAddon -> gameModeAddon.getDescription().getName()).
 			orElse(null);
 	}
+
+
+	/**
+	 * This method allows to get next value from array list after given value.
+	 * @param values Array that should be searched for given value.
+	 * @param currentValue Value which next element should be found.
+	 * @param <T> Instance of given object.
+	 * @return Next value after currentValue in values array.
+	 */
+	public static <T extends Object> T getNextValue(T[] values, T currentValue)
+	{
+		for (int i = 0; i < values.length; i++)
+		{
+			if (values[i].equals(currentValue))
+			{
+				if (i + 1 == values.length)
+				{
+					return values[0];
+				}
+				else
+				{
+					return values[i + 1];
+				}
+			}
+		}
+
+		return currentValue;
+	}
+
+
+	/**
+	 * This method allows to get previous value from array list after given value.
+	 * @param values Array that should be searched for given value.
+	 * @param currentValue Value which previous element should be found.
+	 * @param <T> Instance of given object.
+	 * @return Previous value before currentValue in values array.
+	 */
+	public static <T extends Object> T getPreviousValue(T[] values, T currentValue)
+	{
+		for (int i = 0; i < values.length; i++)
+		{
+			if (values[i].equals(currentValue))
+			{
+				if (i > 0)
+				{
+					return values[i - 1];
+				}
+				else
+				{
+					return values[values.length - 1];
+				}
+			}
+		}
+
+		return currentValue;
+	}
 }