In the Bukkit API, BookMeta.java allows for books to have their author, titles and page data set and retrieved. However, Minecraft 1.8 introduced book "generation" tracking so that copies of books are marked as such.

I would like to suggest an extension of the Bukkit API and subsequent implementation in CraftBukkit of the following:

• enum BookGeneration - Example implementation (unsure if correct values)

  ORIGINAL(0),
  COPY_OF_ORIGINAL(1),
  COPY_OF_COPY(2),
  TATTERED(3)
  

• int getGeneration() - Would return the generation of a book
• void setGeneration(int generation) - Would set the generation of a book

An example use-case for this would be SignShop; to work around complications with written books, code was recently added to recreate a book to a newer "format". However, as the Bukkit API does not expose methods for setting book generation, this metadata is envitably lost.