12.BlockingQueue

What ArrayBlockingQueue is, how to use it, and source analysis of its array, lock, conditions, put/take/offer/poll/add/remove/element/peek methods.

1. What it is. A thread-safe blocking queue. Characteristics: FIFO; blocking insertion when the queue is full and blocking removal when the queue is empty; bounded or unbounded capacity; thread safety. 2. Use cases. Producer-consumer. 3. How to use it. 4. Detailed comparison of BlockingQueue implementations.

What LinkedBlockingQueue is, usage, and source analysis of its linked-list structure, separate put/take locks, conditions, and queue operations.

What PriorityBlockingQueue is, binary-heap basics, usage, and source analysis of growth, offer/put, take, and heap adjustment.

1. What it is. A blocking queue implemented internally with a singly linked structure that does not store elements. A writer must have a reader at the same time in order to proceed, and vice versa; otherwise the writer or reader remains blocked. 2. Usage. 3. Principles. 3.1. Constructor. 3.1.1. Transfer. 3.1.2. QNode. 3.2. put blocking. 3.2.1. Calls TransferQueue.