/*
 * Copyright 1999-2011 Alibaba Group.
 *  
 * 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 com.alibaba.dubbo.remoting;

import java.net.InetSocketAddress;

/**
 * Channel. (API/SPI, Prototype, ThreadSafe)
 * 
 * @see com.alibaba.dubbo.remoting.Client
 * @see com.alibaba.dubbo.remoting.Server#getChannels()
 * @see com.alibaba.dubbo.remoting.Server#getChannel(InetSocketAddress)
 * @author qian.lei
 * @author william.liangf
 */
public interface Channel extends Endpoint {

    /**
     * get remote address.
     * 
     * @return remote address.
     */
    InetSocketAddress getRemoteAddress();

    /**
     * is connected.
     * 
     * @return connected
     */
    boolean isConnected();

    /**
     * has attribute.
     * 
     * @param key key.
     * @return has or has not.
     */
    boolean hasAttribute(String key);

    /**
     * get attribute.
     * 
     * @param key key.
     * @return value.
     */
    Object getAttribute(String key);

    /**
     * set attribute.
     * 
     * @param key key.
     * @param value value.
     */
    void setAttribute(String key,Object value);
    
    /**
     * remove attribute.
     * 
     * @param key key.
     */
    void removeAttribute(String key);

}