QueueFactory.java

QueueFactory-modify.java

public final class QueueFactory {
    
    private static final boolean useUnsafe = DetectionUtil.hasUnsafe();
    private static final InternalLogger LOGGER = InternalLoggerFactory.getInstance(QueueFactory.class);
    
    private QueueFactory() {
        // only use static methods!
    }
    
    
    /**
     * Create a new unbound {@link BlockingQueue} 
     * 
     * @param itemClass  the {@link Class} type which will be used as {@link BlockingQueue} items
     * @return queue     the {@link BlockingQueue} implementation
     */
    public static <T> BlockingQueue<T> createQueue(Class<T> itemClass) {
        // if we run in java >=7 its the best to just use the LinkedTransferQueue which
        // comes with java bundled. See #273
        if (DetectionUtil.javaVersion() >= 6)  {
            return new jsr166y.LinkedTransferQueue<T>();
        }
        
        try {
            if (useUnsafe) {
                return new LinkedTransferQueue<T>();
            }
        } catch (Throwable t) {
            // For whatever reason an exception was thrown while loading the LinkedTransferQueue
            //
            // This mostly happens because of a custom classloader or security policy that did not allow us to access the
            // com.sun.Unmisc class. So just log it and fallback to the old LegacyLinkedTransferQueue that works in all cases
            if (LOGGER.isDebugEnabled()) {
                LOGGER.debug("Unable to instance LinkedTransferQueue, fallback to LegacyLinkedTransferQueue", t);
            }
        }
        
        return new LegacyLinkedTransferQueue<T>();
       
    }
    
    /**
     * Create a new unbound {@link BlockingQueue} 
     * 
     * @param collection  the collection which should get copied to the newly created {@link BlockingQueue}
     * @param itemClass   the {@link Class} type which will be used as {@link BlockingQueue} items
     * @return queue      the {@link BlockingQueue} implementation
     */
    public static <T> BlockingQueue<T> createQueue(Collection<? extends T> collection, Class<T> itemClass) {
        // if we run in java >=7 its the best to just use the LinkedTransferQueue which
        // comes with java bundled. See #273
        if (DetectionUtil.javaVersion() >= 6)  {
            return new jsr166y.LinkedTransferQueue<T>();
        }
        
        try {
            if (useUnsafe) {
                return new LinkedTransferQueue<T>(collection);
            }
        } catch (Throwable t) {
            // For whatever reason an exception was thrown while loading the LinkedTransferQueue
            //
            // This mostly happens because of a custom classloader or security policy that did not allow us to access the
            // com.sun.Unmisc class. So just log it and fallback to the old LegacyLinkedTransferQueue that works in all cases
            if (LOGGER.isDebugEnabled()) {
                LOGGER.debug("Unable to instance LinkedTransferQueue, fallback to LegacyLinkedTransferQueue", t);
            } 
        }
         
        return new LegacyLinkedTransferQueue<T>(collection);
        
    }
}