JeffreyZhao.java

public class BigLockCalculator extends CalculatorBase {

    private interface Status {
        int NotStarted =1;
        int Starting =2;
        int Started =3;
        int Disposed =4;
    }

    private AtomicInteger _status = new AtomicInteger(Status.NotStarted);
    private AtomicInteger _disposingFlag = new AtomicInteger(0);
    private AtomicInteger _startingFlag = new AtomicInteger(0);

    public override void Start() {
        if(_status.get() != Status.NotStarted ) {
            return;
        } 

        if( _startingFlag.compareAndSwap(0,1)) {

            try {
                if(_status.compareAndSwap(Status.NotStarted, Status.Starting)) {

                    StartCore();

                    if(!_status.compareAndSwap(Status.Starting, Status.Started)) { 
                        if(_status.get() == Status.Disposed ) { 
                            DisposeCore();
                            return;
                        } 
                    }
                }

            }finally {
                _startingFlag.compareAndSwap(1,0);
            }
        }
    }

    public override void Dispose() {

        if(_status.get() == Status.Disposed) {
            return;
        } 

        if( _disposingFlag.compareAndSwap(0,1)) {

            try {

                while(true) {

                    int currentStatus =_status.get();

                    if(currentStatus == Status.Disposed) {
                        return;
                    }

                    if(currentStatus == Status.NotStarted && _status.compareAndSwap(currentStatus, Status.Disposed )) {
                        return;
                    }else if(currentStatus == Status.Starting && _status.compareAndSwap(currentStatus, Status.Disposed )){
                        return;
                    }else if(currentStatus == Status.Started && _status.compareAndSwap(currentStatus, Status.Disposed )){
                        DisposeCore();
                    }

                }

            }finally {
                _disposingFlag.compareAndSwap(1,0);
            }
        }
    }
}