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
public void doSomething(File file, Lock lock) {
file.delete(); // Noncompliant
// ...
lock.tryLock(); // Noncompliant
}
Compliant solution
public void doSomething(File file, Lock lock) {
if (!lock.tryLock()) {
// lock failed; take appropriate action
}
if (!file.delete()) {
// file delete failed; take appropriate action
}
}
