public Target getTarget(Timer timer) throws InterruptedException {
            TimeUnit unit = TimeUnit.MILLISECONDS;

            targetLock.tryLock(timer.timeLeft(unit) , unit );
            try {
                if (target == null || !target.isValid())
                    connect(timer);
                return target;
            } finally {
                targetLock.unlock();
            }
        }
Retrieves the path to a file or directory on the local file system
that has been transferred with the vespa file distribution
mechanism.

Intended to be the only real implementation of FileAcquirer.

@author Tony Vaagenes
fileacquirer/src/main/java/com/yahoo/filedistribution/fileacquirer/FileAcquirerImpl.java