org.glassfish.grizzly.http.server.SuspendStatus Maven / Gradle / Ivy

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package org.glassfish.grizzly.http.server;

import org.glassfish.grizzly.ThreadCache;

/**
 * The request/response suspend status bound to a specific thread.
 * 
 * @author Alexey Stashok
 */
public final class SuspendStatus {
    private static final ThreadCache.CachedTypeIndex CACHE_IDX =
            ThreadCache.obtainIndex(SuspendStatus.class, 4);

    public static SuspendStatus create() {
        SuspendStatus status = ThreadCache.takeFromCache(CACHE_IDX);
        if (status == null) {
            status = new SuspendStatus();
        }
        
        assert status.initThread == Thread.currentThread();
        
        status.state = State.NOT_SUSPENDED;

        return status;
    }
    
    private static enum State {
        NOT_SUSPENDED, SUSPENDED, INVALIDATED;
    }
    
    private State state;
    
    private final Thread initThread;

    private SuspendStatus() {
        initThread = Thread.currentThread();
    }
    
    public void suspend() {
        assert Thread.currentThread() == initThread;

        if (state != State.NOT_SUSPENDED) {
            throw new IllegalStateException("Can not suspend. Expected suspend state='" + State.NOT_SUSPENDED + "' but was '" + state +"'");
        }
        
        state = State.SUSPENDED;
    }
    
    boolean getAndInvalidate() {
        assert Thread.currentThread() == initThread;
        
        final boolean wasSuspended = (state == State.SUSPENDED);
        state = State.INVALIDATED;
        
        ThreadCache.putToCache(initThread, CACHE_IDX, this);
        
        return wasSuspended;
    }
    
    public void reset() {
        assert Thread.currentThread() == initThread;
        
        state = State.NOT_SUSPENDED;
    }
}