IoFilter.java

/*
 *  Licensed to the Apache Software Foundation (ASF) under one
 *  or more contributor license agreements.  See the NOTICE file
 *  distributed with this work for additional information
 *  regarding copyright ownership.  The ASF licenses this file
 *  to you under the Apache License, Version 2.0 (the
 *  "License"); you may not use this file except in compliance
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 *
 *    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
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package org.apache.mina.api;

import org.apache.mina.filterchain.ReadFilterChainController;
import org.apache.mina.filterchain.WriteFilterChainController;

/**
 * Filter are interceptors/processors for incoming data received/sent.
 *
 * @author <a href="http://mina.apache.org">Apache MINA Project</a>
 */
public interface IoFilter {

    /**
     * Invoked from an I/O processor thread when a new connection has been created. Because this method is supposed to
     * be called from the same thread that handles I/O of multiple sessions, please implement this method to perform
     * tasks that consumes minimal amount of time such as socket parameter and user-defined session attribute
     * initialization.
     *
     * @param session {@link IoSession} associated with the invocation
     *
     */
    void sessionCreated(IoSession session);

    /**
     * Invoked when a connection has been opened.
     *
     * @param session {@link IoSession} associated with the invocation
     */
    void sessionOpened(IoSession session);

    /**
     * Invoked when a connection is closed.
     *
     * @param session {@link IoSession} associated with the invocation
     */
    void sessionClosed(IoSession session);

    /**
     * Invoked with the related {@link IdleStatus} when a connection becomes idle.
     *
     * @param session {@link IoSession} associated with the invocation
     */
    void sessionIdle(IoSession session, IdleStatus status);

    /**
     * Invoked when a message is received.
     *
     * @param session {@link IoSession} associated with the invocation
     * @param message the incoming message to process
     */
    void messageReceived(IoSession session, Object message, ReadFilterChainController controller);

    /**
     * Invoked when a message is under writing. The filter is supposed to apply the needed transformation.
     *
     * @param session {@link IoSession} associated with the invocation
     * @param message the message to process before writing
     */
    void messageWriting(IoSession session, Object message, WriteFilterChainController controller);
}