/**
 * Copyright 2007-2016, Kaazing Corporation. All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.mina.core.service;

import org.apache.mina.core.session.IoSession;

/**
 * An internal interface to represent an 'I/O processor' that performs
 * actual I/O operations for {@link IoSession}s.  It abstracts existing
 * reactor frameworks such as Java NIO once again to simplify transport
 * implementations.
 *
 * @author <a href="http://mina.apache.org">Apache MINA Project</a>
 * 
 * @param <T> the type of the {@link IoSession} this processor can handle
 */
public interface IoProcessor<T extends IoSession> {

    /**
     * Returns <tt>true</tt> if and if only {@link #dispose()} method has
     * been called.  Please note that this method will return <tt>true</tt>
     * even after all the related resources are released.
     */
    boolean isDisposing();
    
    /**
     * Returns <tt>true</tt> if and if only all resources of this processor
     * have been disposed.
     */
    boolean isDisposed();
    
    /**
     * Releases any resources allocated by this processor.  Please note that 
     * the resources might not be released as long as there are any sessions
     * managed by this processor.  Most implementations will close all sessions
     * immediately and release the related resources.
     */
    void dispose();
    
    /**
     * Adds the specified {@code session} to the I/O processor so that
     * the I/O processor starts to perform any I/O operations related
     * with the {@code session}.
     */
    void add(T session);

    /**
     * Flushes the internal write request queue of the specified
     * {@code session}.
     */
    void flush(T session);

    /**
     * Controls the traffic of the specified {@code session} depending of the
     * {@link IoSession#isReadSuspended()} and {@link IoSession#isWriteSuspended()}
     * flags
     */
    void updateTrafficControl(T session);

    /**
     * Removes and closes the specified {@code session} from the I/O
     * processor so that the I/O processor closes the connection
     * associated with the {@code session} and releases any other related
     * resources.
     */
    void remove(T session);
}
