首先需要明確的是，Condition只工作在排他鎖，一個排他鎖可以有多個Condition,不過Condition的程式碼其實是在AQS裡的

public class ConditionObject implements Condition, java.io.Serializable {
        private static final long serialVersionUID = 1173984872572414699L;
        /** First node of condition queue. */
        private transient Node firstWaiter;
        
 
/** Last node of condition queue. */
        private transient Node lastWaiter;

　　順便複習一下Node，

    static final class Node {
        /** Marker to indicate a node is waiting in shared mode */
        static final Node SHARED = new Node();
        /** Marker to indicate a node is waiting in exclusive mode 
 
*/
        static final Node EXCLUSIVE = null;

        /** waitStatus value to indicate thread has cancelled */
        static final int CANCELLED =  1;
        /** waitStatus value to indicate successor's thread needs unparking */
        static final int SIGNAL    = -1;
        /** waitStatus value to indicate thread is waiting on condition 
 
*/
        static final int CONDITION = -2;
        /**
         * waitStatus value to indicate the next acquireShared should
         * unconditionally propagate
         */
        static final int PROPAGATE = -3;

        volatile int waitStatus;

        volatile Node prev;

        volatile Node next;

        volatile Thread thread;

        Node nextWaiter;

　　上面需要注意的是在同步佇列中的時候，是有前驅和後繼的prev，next，但是在條件佇列中只有nextWaiter，沒有前驅，因為沒必要