Using Java $-$ A writer prepares his book. He works with two processes; the write and the edit. When he is in the write phase is prevented to go to the edit phase by using a lock mechanism. The same with the edit stage. Prepare a program that provides these possibilities using the executor framework.

With this framework it is needed to prepare the runnable objects and leave the executor to run them.

Two tasks $($classes$)-$writeOn,writeOff$-$ are introduced and are used for the executor. A mutex is used by the basic class $($Book$)$ for mutual exclusion. A condition can be used to suspend a task.

The output will be alternately: Write On now, Write Off now. $($writdeit$.$java$)$