Hadoop源码分析7: IPC流程(1) 主要类
1.服务器端主要类
public abstractclass Server
{
public static final ByteBuffer HEADER =ByteBuffer.wrap("hrpc".getBytes());
public static final byte CURRENT_VERSION =4;
private static finalThreadLocal＜Server＞ SERVER= new ThreadLocal＜Server＞();
private static finalThreadLocal＜Call＞ CurCall = newThreadLocal＜Call＞();
private String bindAddress;
private int port;
private int handlerCount;
private int readThreads;
private Class＜? extendsWritable＞ paramClass;
private int maxIdleTime;
private int thresholdIdleConnections;
private Configuration conf;
private int maxQueueSize;
private final int maxRespSize;
private int socketSendBufferSize;
volatile private boolean running =true;
privateBlockingQueue＜Call＞ callQueue;
privateList＜Connection＞ connectionList = Collections.synchronizedList(newLinkedList＜Connection＞());
private Listener listener= null;
private Responder responder= null;
private int numConnections = 0;
private Handler[]handlers = null;
//内部类Server.Call，包装请求参数
private static class Call {
private int id; // theclient's call id
private Writable param; // the parameter passed
private Connection connection;
private ByteBuffer response;
}
//内部类Server.Listener ,线程
private class Listener extendsThread {
privateServerSocketChannel acceptChannel =null; //the accept channel
privateSelector selector = null; //theselector that we use for the server
private Reader[]readers = null;
private int currentReader =0;
private InetSocketAddressaddress; //the address we bind at
private Random rand = newRandom();
private longlastCleanupRunTime = 0;
private ExecutorServicereadPool;
//内部类Server.Listener.Reader , 线程
privateclass Reader implementsRunnable {
privatevolatile boolean adding = false;
privateSelector readSelector =null;
}
//内部类Server.Responder , 线程
privateclass Responder extendsThread {
privateSelector writeSelector;
private intpending;
}
//内部类Server.Connection，而Client.Connection是线程
publicclass Connection {
privateboolean rpcHeaderRead = false; // if initial rpc header isread
privateboolean headerRead = false;
privateSocketChannel channel;
privateByteBuffer data;
privateByteBuffer dataLengthBuffer;
privateLinkedList＜Call＞ responseQueue;
privatevolatile int rpcCount = 0; // number of outstanding rpcs
privatelong lastContact;
private intdataLength;
privateSocket socket;
privateString hostAddress;
private intremotePort;
privateInetAddress addr;
ConnectionHeader header = new ConnectionHeader();
Class＜？＞ protocol;
privateAuthMethod authMethod;
}
//内部类Server.Handler，线程
private class Handler extendsThread {
}
}
2.客户端主要类
public classClient {
privateHashtable＜ConnectionId, Connection＞ connections = new Hashtable＜ConnectionId,Connection＞();
privateClass＜？ extendsWritable＞ valueClass;
private intcounter; // counter for call ids
privateAtomicBoolean running = new AtomicBoolean(true); // if clientruns
finalprivate Configuration conf;
privateSocketFactory socketFactory; // how tocreate sockets
private intrefCount = 1;
//内部类Client.Call
private class Call {
int id; // callid
Writable param; //parameter
Writable value; // value,null if error
IOException error; // exception, null ifvalue
boolean done;
}
//内部类Client.Connection ,线程 ，而Server.Connection不是线程
private class Connection extendsThread {
privateInetSocketAddress server; // server ip:port
privateString serverPrincipal; // server's krb5principal name
privateConnectionHeader header; // connection header
privatefinal ConnectionId remoteId; // connection id
privateAuthMethod authMethod; // authentication method
private Socket socket = null; // connected socket
privateDataInputStream in;
privateDataOutputStream out;
private intrpcTimeout;
private intmaxIdleTime;
private intmaxRetries; //the max. no. of retries for socket connections
privateboolean tcpNoDelay; // if T then disable Nagle's Algorithm
private intpingInterval; /
privateHashtable＜Integer, Call＞ calls= new Hashtable＜Integer, Call＞();
privateAtomicLong lastActivity = new AtomicLong();
privateAtomicBoolean shouldCloseConnection = new AtomicBoolean();
private IOException closeException; // closereason
//内部类Client.Connection.PingInputStream
private class PingInputStream extendsFilterInputStream {
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//内部类Client.ParallelCall
privateclass ParallelCall extends Call {
privateParallelResults results;
private intindex;
}
//内部类Client.ParallelResults
private static classParallelResults {
privateWritable[] values;
privateint size;
privateint count;
//
}
//内部类Client.ConnectionId
static class ConnectionId {
InetSocketAddress address;
UserGroupInformationticket;
Class＜？＞protocol;
privatestatic final int PRIME = 16777619;
privateint rpcTimeout;
privateString serverPrincipal;
privateint maxIdleTime;
privateint maxRetries; //the max. no. of retries for socketconnections
privateboolean tcpNoDelay; // if T then disable Nagle's Algorithm
privateint pingInterval; // how often sends ping to the server inmsecs
}
}
3.RPC主要类
public class RPC {
private static ClientCache CLIENTS=newClientCache();
//内部类RPC.ClientCache
static privateclass ClientCache {
private Map＜SocketFactory, Client＞ clients= new HashMap＜SocketFactory, Client＞();
}
//内部类RPC.Invocation ，只是一个包装请求参数的普通类，不执行动态代理方法
private static class Invocationimplements Writable, Configurable {
privateString methodName;
privateClass[] parameterClasses;
privateObject[] parameters;
privateConfiguration conf;
}
//内部类RPC.Invoker ，执行动态代理方法
private static class Invoker implementsInvocationHandler {
privateClient.ConnectionId remoteId;
privateClient client;
privateboolean isClosed = false;
}
//内部类RPC.VersionMismatch
public static classVersionMismatch extends IOException {
privateString interfaceName;
privatelong clientVersion;
privatelong serverVersion;
}
//内部类RPC.Server ，添加了两个成员 instance，verbose
public static class Server extendsorg.apache.hadoop.ipc.Server {
private Object instance;
private boolean verbose;
}
}
4.其他类
//IPC所有类都要实现的接口
publicinterface VersionedProtocol {
publiclong getProtocolVersion(String protocol, longclientVersion) throws IOException;
}
//连接头信息，包括protocol，userGroupInformation ， authMethod三个成员变量
class ConnectionHeader implementsWritable {
private String protocol;
private UserGroupInformation ugi =null;
private AuthMethod authMethod; ......
}
//访问状况，包括SUCCESS、ERROR、FATAL
enum Status{
SUCCESS(0),
ERROR(1),
FATAL(-1);.......
}
//包装IO异常
publicclass RemoteException extendsIOException {
}
