[FIXED] How to return object in conditional statement scope in Java?

Issue

I'm learning java spring. I have to get a user then save the Foo into the database. The user object is Optional, so I must put the new Foo in ifPresent then how can I return the result while I can't use let like javascript?

class="lang-java prettyprint-override">  @PostMapping("/foo")
  public ResponseEntity<Foo> createFoo(@Valid @RequestBody Checkout checkout) throws URISyntaxException {
    Optional<User> _user = userRepository.findById(userId);
    _user.ifPresent(
      user-> 
        Foo _foo = checkout.getFoo();
        _foo.setUser(user);
        Foo foo = checkoutService.saveFoo(_foo );
      }
    );

    return ResponseEntity
      .created(new URI("/api/foo/" + foo .getId()))
      .headers(HeaderUtil.createEntityCreationAlert(applicationName, true, ENTITY_NAME, result.getId().toString()))
      .body(foo );```

Solution

You can do something like this:

 @PostMapping("/foo")
  public ResponseEntity<Foo> createFoo(@Valid @RequestBody Checkout checkout) throws URISyntaxException {
    Optional<User> _user = userRepository.findById(userId);
    Foo foo = _user.map(user -> {
        Foo _foo = checkout.getFoo();
        _foo.setUser(user);
        return checkoutService.saveFoo(_foo);
    }).orElse(null);

    return ResponseEntity
      .created(new URI("/api/foo/" + foo .getId()))
      .headers(HeaderUtil.createEntityCreationAlert(applicationName, true, ENTITY_NAME, result.getId().toString()))
      .body(foo );
 }

the map allows to return another type of object in this case we return the value returned by checkoutService.saveFoo(_foo); and we store it in the foo variable, in case userRepository.findById(userId) returns null, you can use .orElse() as comments @QBrute.

    Foo foo = _user.map(user -> {
        Foo _foo = checkout.getFoo();
        _foo.setUser(user);
        return checkoutService.saveFoo(_foo);
    }).orElse(<default value>);

Answered By - fneira
Answer Checked By - Robin (JavaFixing Admin)