Java™ How To Program (Early Objects), Tenth Edition

Synchronization and State Dependence

In a multithreaded producer/consumer relationship, a producer thread generates data and places it in a shared object called a buffer. A consumer thread reads data from the buffer. This relationship requires synchronization to ensure that values are produced and consumed properly. All operations on mutable data that’s shared by multiple threads (e.g., the data in the buffer) must be guarded with a lock to prevent corruption, as discussed in Section 23.4. Operations on the buffer data shared by a producer and consumer thread are also state dependent—the operations should proceed only if the buffer is in the correct state. If the buffer is in a not-full state, the producer may produce; if the buffer is in a ...