When the return value of a function call contains the operation status code, this value should be tested to make sure the operation completed
successfully.
This rule raises an issue when the return values of the following are ignored:
-
java.io.File operations that return a status code (except mkdirs)
-
Iterator.hasNext()
-
Enumeration.hasMoreElements()
-
Lock.tryLock()
- non-void
Condition.await* methods
-
CountDownLatch.await(long, TimeUnit)
-
Semaphore.tryAcquire
-
BlockingQueue: offer, remove
Noncompliant code example
fun doSomething(file: File, lock: Lock) {
file.delete() // Noncompliant
// ...
lock.tryLock() // Noncompliant
}
Compliant solution
fun doSomething(file: File, lock: Lock) {
if (!file.delete()) {
// file delete failed; take appropriate action
}
if (!lock.tryLock()) {
// lock failed; take appropriate action
}
}
