ZooKeeper源码(2)cli,client,common,jmx,version包

jmx包

从ComonNames文件中知道，org.apache.ZooKeeperService很重要

//CommonNames.javapublic class CommonNames {    public static final String DOMAIN="org.apache.ZooKeeperService";    public static final String DATA_TREE_KEY="DataTree";    public static final String STANDALONE_SERVER_KEY="StandaloneServer";}//ManagedUtil.java//配置log4j//MBeanRegistry.java//不懂JMX,看不懂//ZKMBeabInfo.java//ZooKeeper要监控的bean的接口public interface ZKMBeanInfo {    public String getName();    public boolean isHidden();}

cli包

这个包是解析zk-cli的命令的,所有命令的就是继承自CliCommand类。看到这么命名的，就基本知道是命令模式了。

abstract public class CliCommand {    protected ZooKeeper zk;    //要自己设置    protected PrintStream out; //默认System.out    protected PrintStream err; //默认System.err    private String cmdStr;    //这个是子类传入的,如"create"    private String optionStr; //这个也是子类传入的,如"[-s] [-e] [-c] [-t ttl] path [data] [acl]"    public void addToMap(Map<String, CliCommand> cmdMap) {        //记录下命令        .3        cmdMap.put(cmdStr, this);    }    abstract public CliCommand parse(String cmdArgs[]) throws CliParseException;    abstract public boolean exec() throws CliException;

看一下CreateCommand的实现，结果发现比3.4.10还多了一些选项

public class CreateCommand extends CliCommand {    private static Options options = new Options();    private String[] args;    private CommandLine cl;    static {        options.addOption(new Option("e", false, "ephemeral"));        options.addOption(new Option("s", false, "sequential"));        options.addOption(new Option("c", false, "container"));        options.addOption(new Option("t", true, "ttl"));    }    public CreateCommand() {        super("create", "[-s] [-e] [-c] [-t ttl] path [data] [acl]");    }}    //用于解析输入的命令    public CliCommand parse(String[] cmdArgs){ ... }    //用于执行解析的命令    //委派给父类的ZooKeeper来执行    public boolean exec() throws CliException {    //...    String newPath = hasT ?     zk.create(path, data, acl, flags, new Stat(), ttl) :     zk.create(path, data, acl, flags);    //...    }

来，那就看看全部的命令吧

//e->ephemeral, s->sequential//c->container, t->ttlpublic class CreateCommand extends CliCommand {    public CreateCommand() {        super("create", "[-s] [-e] [-c] [-t ttl] path [data] [acl]");    }}//v->versionpublic class DeleteCommand extends CliCommand {    public DeleteCommand() {        super("delete", "[-v version] path");    }}public class DeleteAllCommand extends CliCommand {    public DeleteAllCommand() {        this("deleteall");    }}//s->stats, w->watchpublic class GetCommand extends CliCommand {    private static Options options = new Options();    public GetCommand() {        super("get", "[-s] [-w] path");    }}//s->stats, v->versionpublic class SetCommand extends CliCommand {    public SetCommand() {        super("set", "[-s] [-v version] path data");    }}public class Ls2Command extends CliCommand {    public Ls2Command() {        super("ls2", "path [watch]");    }}//ls ? ->help//s->stat, w->watch, r->recursepublic class LsCommand extends CliCommand {    public LsCommand() {        super("ls", "[-s] [-w] [-R] path");    }}//b->bytes quota, n->num quotapublic class SetQuotaCommand extends CliCommand {    public SetQuotaCommand() {        super("setquota", "-n|-b val path");   }}public class ListQuotaCommand extends CliCommand {    public ListQuotaCommand() {        super("listquota", "path");    }}//b->bytes quota, n->num quotapublic class DelQuotaCommand extends CliCommand {    public DelQuotaCommand() {        super("delquota", "[-n|-b] path");    }}//s->statspublic class GetAclCommand extends CliCommand {    public GetAclCommand() {        super("getAcl", "[-s] path");    }}//s->stats, v->versionpublic class SetAclCommand extends CliCommand {    public SetAclCommand() {        super("setAcl", "[-s] [-v version] path acl");    }}public class AddAuthCommand extends CliCommand {    public AddAuthCommand() {        super("addauth", "scheme auth");    }}public class CloseCommand extends CliCommand {    public CloseCommand() {        super("close", "");    }}//s->stats, w->watch//c->client connection stringpublic class GetConfigCommand extends CliCommand {    private static Options options = new Options();    public GetConfigCommand() {        super("config", "[-c] [-w] [-s]");    }}//s->stats//v->required current config version//file->path of config file to parse for membership//members->comma-separated list of config strings for non-incremental reconfig//add->comma-separated list of config strings for new servers//remove->comma-separated list of server IDs to removepublic class ReconfigCommand extends CliCommand {    public ReconfigCommand() {        super("reconfig", "[-s] " +                "[-v version] " +                "[[-file path] | " +                "[-members serverID=host:port1:port2;port3[,...]*]] | " +                "[-add serverId=host:port1:port2;port3[,...]]* " +                "[-remove serverId[,...]*]");    }}//c->child watcher type//d->data watcher type//a->any watcher type//l->remove locally when there is no server connectionpublic class RemoveWatchesCommand extends CliCommand {    public RemoveWatchesCommand() {        super("removewatches", "path [-c|-d|-a] [-l]");    }}//w->watchpublic class StatCommand extends CliCommand {    public StatCommand() {        super("stat", "[-w] path");    }}public class SyncCommand extends CliCommand {    public SyncCommand() {        super("sync", "path");    }}

client包

//ConnectStringParser//解析localhost:2181,localhost:2182这种//全部加入一个Listpublic final class ConnectStringParser {    private static final int DEFAULT_PORT = 2181;    private final String chrootPath;    private final ArrayList<InetSocketAddress> serverAddresses = new ArrayList<InetSocketAddress>();}//FourLetterWordMain//四字命令的客户端吧//只是为了便于测试，使用了SSLSocket//HostProvider//StaticHostProvider//cli连接时，是可以传入多个地址的，这里的作用就是随机分配一个地址，也算负载均衡吧//没错，还有篇论文，这里用的将服务器打乱随机选一个。https://issues.apache.org/jira/browse/ZOOKEEPER-1355//ZKClientConfig//配置文件//ZooKeeperSaslClient//SASL全称Simple Authentication and Security Layer，是一种用来扩充C/S模式验证能力的机制。在Postfix可以利用SASL来判断用户是否有权使用转发服务，或是辨认谁在使用你的服务器。

common包

AtomicFileOutputStream: 但是没有看出哪里原子了…这个类是从HDFS直接弄过来的

public class AtomicFileOutputStream extends FilterOutputStream {    private static final String TMP_EXTENSION = ".tmp";    private final File origFile;    private final File tmpFile;        public AtomicFileOutputStream(File f) throws FileNotFoundException {        // Code unfortunately must be duplicated below since we can't assign        // anything        // before calling super        super(new FileOutputStream(new File(f.getParentFile(), f.getName()                + TMP_EXTENSION)));        origFile = f.getAbsoluteFile();        tmpFile = new File(f.getParentFile(), f.getName() + TMP_EXTENSION)                .getAbsoluteFile();    }

AtomicFileWritingIdiom：为了提供文件的原子写入，Based on the org.apache.zookeeper.server.quorum.QuorumPeer.writeLongToFile(…) idiom ，using the HDFS AtomicFileOutputStream class.

public class AtomicFileWritingIdiom {    public static interface OutputStreamStatement {        public void write(OutputStream os) throws IOException;    }    public static interface WriterStatement {        public void write(Writer os) throws IOException;    }    public AtomicFileWritingIdiom(File targetFile, OutputStreamStatement osStmt)  throws IOException {        this(targetFile, osStmt, null);    }    public AtomicFileWritingIdiom(File targetFile, WriterStatement wStmt)  throws IOException {        this(targetFile, null, wStmt);    }    private AtomicFileWritingIdiom(File targetFile, OutputStreamStatement osStmt, WriterStatement wStmt)  throws IOException {        AtomicFileOutputStream out = null;        boolean error = true;        try {            out = new AtomicFileOutputStream(targetFile);            if (wStmt == null) {                // execute output stream operation                osStmt.write(out);            } else {                BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(out));                // execute writer operation and flush                wStmt.write(bw);                bw.flush();            }            out.flush();            // everything went ok            error = false;        } finally {            // nothing interesting to do if out == null            if (out != null) {                if (error) {                    // worst case here the tmp file/resources(fd) are not cleaned up                    // and the caller will be notified (IOException)                    out.abort();                } else {                    // if the close operation (rename) fails we'll get notified.                    // worst case the tmp file may still exist                    IOUtils.closeStream(out);                }            }        }    }}

IOUtil

closeStream(Closeable stream)cleanup(Logger log, Closeable... closeables)copyBytes(InputStream in, OutputStream out,int buffSize, boolean close) copyBytes(InputStream in, OutputStream out, int buffSize)

PathTrie:有空好好研究，这东西是一个单词树

PathUtil: 验证路径没有错, 和Window里面的//进行转换

public static void validatePath(String path, boolean isSequential) public static void validatePath(String path)public static String normalizeFileSystemPath(String path)

StringUtil: 分割和拼接字符串，默认是分割成String[]，这里改进为列表

public static List<String> split(String value, String separator)public static String joinStrings(List<String> list, String delim)

Time: 时间，略过

X509Util和ZKConfig大多属性标记废弃了,X.509是一种非常通用的证书格式。所有的证书都符合ITU-T X.509国际标准，因此(理论上)为一种应用创建的证书可以用于任何其他符合X.509标准的应用。

version包

就一个VerGen类，输出当前ZooKeeper版本信息