| // |
| // ======================================================================== |
| // Copyright (c) 1995-2015 Mort Bay Consulting Pty. Ltd. |
| // ------------------------------------------------------------------------ |
| // All rights reserved. This program and the accompanying materials |
| // are made available under the terms of the Eclipse Public License v1.0 |
| // and Apache License v2.0 which accompanies this distribution. |
| // |
| // The Eclipse Public License is available at |
| // http://www.eclipse.org/legal/epl-v10.html |
| // |
| // The Apache License v2.0 is available at |
| // http://www.opensource.org/licenses/apache2.0.php |
| // |
| // You may elect to redistribute this code under either of these licenses. |
| // ======================================================================== |
| // |
| |
| package org.eclipse.jetty.io; |
| |
| import java.io.IOException; |
| import java.nio.channels.ClosedChannelException; |
| import java.nio.channels.ReadPendingException; |
| import java.text.SimpleDateFormat; |
| import java.util.Date; |
| import java.util.concurrent.atomic.AtomicReference; |
| |
| import org.eclipse.jetty.util.Callback; |
| import org.eclipse.jetty.util.log.Log; |
| import org.eclipse.jetty.util.log.Logger; |
| |
| /** |
| * A Utility class to help implement {@link EndPoint#fillInterested(Callback)} |
| * by keeping state and calling the context and callback objects. |
| */ |
| public abstract class FillInterest |
| { |
| private final static Logger LOG = Log.getLogger(FillInterest.class); |
| private final AtomicReference<Callback> _interested = new AtomicReference<>(null); |
| private Throwable _lastSet; |
| |
| protected FillInterest() |
| { |
| } |
| |
| /** |
| * Call to register interest in a callback when a read is possible. |
| * The callback will be called either immediately if {@link #needsFillInterest()} |
| * returns true or eventually once {@link #fillable()} is called. |
| * |
| * @param callback the callback to register |
| * @throws ReadPendingException if unable to read due to pending read op |
| */ |
| public void register(Callback callback) throws ReadPendingException |
| { |
| if (callback == null) |
| throw new IllegalArgumentException(); |
| |
| if (_interested.compareAndSet(null, callback)) |
| { |
| if (LOG.isDebugEnabled()) |
| { |
| LOG.debug("{} register {}",this,callback); |
| _lastSet=new Throwable(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS").format(new Date()) + ":" + Thread.currentThread().getName()); |
| } |
| } |
| else |
| { |
| LOG.warn("Read pending for {} prevented {}", _interested, callback); |
| if (LOG.isDebugEnabled()) |
| LOG.warn("callback set at ",_lastSet); |
| throw new ReadPendingException(); |
| } |
| try |
| { |
| if (LOG.isDebugEnabled()) |
| LOG.debug("{} register {}",this,callback); |
| needsFillInterest(); |
| } |
| catch (Throwable e) |
| { |
| onFail(e); |
| } |
| } |
| |
| /** |
| * Call to signal that a read is now possible. |
| */ |
| public void fillable() |
| { |
| Callback callback = _interested.get(); |
| if (LOG.isDebugEnabled()) |
| LOG.debug("{} fillable {}",this,callback); |
| if (callback != null && _interested.compareAndSet(callback, null)) |
| callback.succeeded(); |
| else if (LOG.isDebugEnabled()) |
| LOG.debug("{} lost race {}",this,callback); |
| } |
| |
| /** |
| * @return True if a read callback has been registered |
| */ |
| public boolean isInterested() |
| { |
| return _interested.get() != null; |
| } |
| |
| public boolean isCallbackNonBlocking() |
| { |
| Callback callback = _interested.get(); |
| return callback!=null && callback.isNonBlocking(); |
| } |
| |
| /** |
| * Call to signal a failure to a registered interest |
| * |
| * @param cause the cause of the failure |
| * @return true if the cause was passed to a {@link Callback} instance |
| */ |
| public boolean onFail(Throwable cause) |
| { |
| Callback callback = _interested.get(); |
| if (callback != null && _interested.compareAndSet(callback, null)) |
| { |
| callback.failed(cause); |
| return true; |
| } |
| return false; |
| } |
| |
| public void onClose() |
| { |
| Callback callback = _interested.get(); |
| if (callback != null && _interested.compareAndSet(callback, null)) |
| callback.failed(new ClosedChannelException()); |
| } |
| |
| @Override |
| public String toString() |
| { |
| return String.format("FillInterest@%x{%b,%s}", hashCode(), _interested.get(), _interested.get()); |
| } |
| |
| /** |
| * Register the read interest |
| * Abstract method to be implemented by the Specific ReadInterest to |
| * schedule a future call to {@link #fillable()} or {@link #onFail(Throwable)} |
| * |
| * @throws IOException if unable to fulfill interest in fill |
| */ |
| abstract protected void needsFillInterest() throws IOException; |
| } |