Synchronization of Threads in Java

Question

You have a storage object O.

Assume you have n reader methods and one writer method in a thread. If the writer method is called by a thread, none of the reader methods should be able to access O, but if a reader method accesses O, any other reader may access O but not the writer. Can I somehow implement this behaviour using "synchronized" statements in Java? If not: How else could I achieve this?

Thank you in advance.

Answer 1

You could use a ReadWriteLock . You allocate it somewhere where the reader and writer threads can access it. Maybe pass it into their constructors.

ReadWriteLock readWriteLock = new ReentrantReadWriteLock();

Readers would do:

Lock lock = readWriteLock.readLock();
lock.lock();
try {
  // do read operations here...
} finally {
  lock.unlock();
}

Writers would do:

Lock lock = readWriteLock.writeLock();
lock.lock();
try {
  // do write operations here...
} finally {
  lock.unlock();
}