Is your feature request related to a problem? Please describe.

I am using a plugin that is basically an extension of this plugin. Currently there is no way to sell/buy all items to/from a shop even using PreTransationEvent.

Describe the solution you'd like

The dev said that it would be useful if PreTransactionEvent had a .setAmount(int amount, boolean adjustPrice) that basically gets sets the amount of the item being sold and the boolean "adjustPrice" if true would basically update the price to fit the amount of new items.

Thanks a tonne :)

This should already be possible by editing the price and stock in the the PreTransactionEvent similarly to how the PartialTransactionModule does it.