feature: resolve #1282 for Lockable Object pattern. (#1702)

* Added Lockable-Object pattern. Closes #1282.

* Refactor method name.

* Refactor sonar lint bugs.

* Added tests and enum Constants.

* Increase coverage.

* Changed @Data to Getters and Setters.

* Iluwatar's comment on pull request #1702.

* Fixed codes mells.

* Incremented wait time to 3 seconds.

* Reduced wait time to 2 seconds.

* Cleaned Code Smells.

* Incremented wait time, removed cool down.

* Refactored README.md file.

Co-authored-by: Subhrodip Mohanta <subhrodipmohanta@gmail.com>

lockable-object/src/main/java/com/iluwatar/lockableobject/Lockable.java

@@ -0,0 +1,43 @@
+package com.iluwatar.lockableobject;
+
+import com.iluwatar.lockableobject.domain.Creature;
+
+/** This interface describes the methods to be supported by a lockable-object. */
+public interface Lockable {
+
+  /**
+   * Checks if the object is locked.
+   *
+   * @return true if it is locked.
+   */
+  boolean isLocked();
+
+  /**
+   * locks the object with the creature as the locker.
+   *
+   * @param creature as the locker.
+   * @return true if the object was locked successfully.
+   */
+  boolean lock(Creature creature);
+
+  /**
+   * Unlocks the object.
+   *
+   * @param creature as the locker.
+   */
+  void unlock(Creature creature);
+
+  /**
+   * Gets the locker.
+   *
+   * @return the Creature that holds the object. Returns null if no one is locking.
+   */
+  Creature getLocker();
+
+  /**
+   * Returns the name of the object.
+   *
+   * @return the name of the object.
+   */
+  String getName();
+}