rspec/rules/S4064/java/rule.adoc

== Why is this an issue?

No matter whether the optional value is present or not, ``++Optional::orElse++``'s argument will always be executed. This is usually not what the developer intended when the content of the ``++orElse()++`` call has side effects. Even when no side effect is involved, the unnecessary computation of the ``++orElse()++`` clause might be a waste of resources.


Calls to https://docs.oracle.com/javase/8/docs/api/java/util/Optional.html#orElse-T-[``++Optional::orElse++``] should be replaced with https://docs.oracle.com/javase/8/docs/api/java/util/Optional.html#orElseGet-java.util.function.Supplier-[``++Optional::orElseGet++``] whenever the alternative value is not a constant.


This rule raises an issue when ``++Optional::orElse++`` is called with an argument that doesn't evaluate to a constant value.


=== Noncompliant code example

[source,java]
----
Optional<MyObj> opt = getOptMyObj();
MyObj myObj = opt.orElse(new MyObj());  // Noncompliant
----


=== Compliant solution

[source,java]
----
Optional<MyObj> opt = getOptMyObj();
MyObj myObj = opt.orElseGet(MyObj::new); 
Optional<String> optString = getOptString();
String str = opt.orElse("hello");
----


ifdef::env-github,rspecator-view[]

'''
== Implementation Specification
(visible only on this page)

=== Message

Use "orElseGet" here instead of "orElse".


=== Highlighting

``++orElse++``


'''
== Comments And Links
(visible only on this page)

=== on 27 Jun 2017, 17:33:18 Ann Campbell wrote:
https://groups.google.com/forum/?pli=1#!topic/sonarqube/b_DFJ2ual6E

endif::env-github,rspecator-view[]