LeifW/cheat_sheet.md

## cheat_sheet.md

      
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              cheat_sheet.md
            
          
Optional
Either
CompletableFuture


Create success value
Optional.of
Either.right
CompletableFuture.completedFuture


Create failure value
Optional.empty
Either.left
f = new CompletableFuture(); f.completeExceptionally; return f


Apply function to success case
.map
.map
.thenApply


Apply a function to success case that may also fail
.flatMap
.flatMap
.thenCompose


Handle both failure & sucess cases at once
.map().orElse()
.fold
.handle
	Optional	Either	CompletableFuture
Create success value	Optional.of	Either.right	CompletableFuture.completedFuture
Create failure value	Optional.empty	Either.left	f = new CompletableFuture(); f.completeExceptionally; return f
Apply function to success case	.map	.map	.thenApply
Apply a function to success case that may also fail	.flatMap	.flatMap	.thenCompose
Handle both failure & sucess cases at once	.map().orElse()	.fold	.handle