SelectorProviderImpl.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
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package sun.nio.ch;

import java.io.IOException;
import java.net.ProtocolFamily;
import java.nio.channels.DatagramChannel;
import java.nio.channels.Pipe;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.nio.channels.spi.AbstractSelector;
import java.nio.channels.spi.SelectorProvider;

// 选择器工厂的抽象实现，实现了SelectorProvider的大部分特性（除了生成Selector没有实现）
public abstract class SelectorProviderImpl extends SelectorProvider {
    
    // 生产Selector，由各平台自行实现
    public abstract AbstractSelector openSelector() throws IOException;
    
    // 构造一个未绑定的[客户端Socket]，内部初始化了该Socket的文件描述符
    public SocketChannel openSocketChannel() throws IOException {
        return new SocketChannelImpl(this);
    }
    
    // 构造一个未绑定的ServerSocket，本质是创建了[服务端Socket(监听)]，内部初始化了该Socket的文件描述符
    public ServerSocketChannel openServerSocketChannel() throws IOException {
        return new ServerSocketChannelImpl(this);
    }
    
    // 构造DatagramSocket通道，内部初始化了该Socket的文件描述符
    public DatagramChannel openDatagramChannel() throws IOException {
        return new DatagramChannelImpl(this);
    }
    
    // 构造DatagramSocket通道，内部初始化了该Socket的文件描述符，其支持的协议族由参数family指定
    public DatagramChannel openDatagramChannel(ProtocolFamily family) throws IOException {
        return new DatagramChannelImpl(this, family);
    }
    
    // 生产Pipe
    public Pipe openPipe() throws IOException {
        return new PipeImpl(this);
    }
    
}