65 lines
1.5 KiB
Plaintext
65 lines
1.5 KiB
Plaintext
Just as there is little justification for writing your own String class, there is no good reason to re-define one of the existing, standard functional interfaces.
|
|
|
|
|
|
Doing so may seem tempting, since it would allow you to specify a little extra context with the name. But in the long run, it will be a source of confusion, because maintenance programmers will wonder what is different between the custom functional interface and the standard one.
|
|
|
|
|
|
== Noncompliant Code Example
|
|
|
|
----
|
|
@FunctionalInterface
|
|
public interface MyInterface { // Noncompliant
|
|
double toDouble(int a);
|
|
}
|
|
|
|
@FunctionalInterface
|
|
public interface ExtendedBooleanSupplier { // Noncompliant
|
|
boolean get();
|
|
default boolean isFalse() {
|
|
return !get();
|
|
}
|
|
}
|
|
|
|
public class MyClass {
|
|
private int a;
|
|
public double myMethod(MyInterface instance){
|
|
return instance.toDouble(a);
|
|
}
|
|
}
|
|
----
|
|
|
|
|
|
== Compliant Solution
|
|
|
|
----
|
|
@FunctionalInterface
|
|
public interface ExtendedBooleanSupplier extends BooleanSupplier { // Compliant, extends java.util.function.BooleanSupplier
|
|
default boolean isFalse() {
|
|
return !getAsBoolean();
|
|
}
|
|
}
|
|
|
|
public class MyClass {
|
|
private int a;
|
|
public double myMethod(IntToDoubleFunction instance){
|
|
return instance.applyAsDouble(a);
|
|
}
|
|
}
|
|
----
|
|
|
|
|
|
ifdef::env-github,rspecator-view[]
|
|
|
|
'''
|
|
== Implementation Specification
|
|
(visible only on this page)
|
|
|
|
include::message.adoc[]
|
|
|
|
'''
|
|
== Comments And Links
|
|
(visible only on this page)
|
|
|
|
include::comments-and-links.adoc[]
|
|
endif::env-github,rspecator-view[]
|