Zookeeper节点类型

来源：互联网发布：如何培养英语思维知乎编辑：程序博客网时间：2024/06/14 20:30
http://blog.csdn.net/desilting/article/details/41043837 原文
public enum CreateMode {       /**     * 持久节点：节点创建后，会一直存在，不会因客户端会话失效而删除；     */    PERSISTENT (0, false, false),    /**     * 持久顺序节点：基本特性与持久节点一致，创建节点的过程中，zookeeper会在其名字后自动追加一个单调增长的数字后缀，作为新的节点名；      */    PERSISTENT_SEQUENTIAL (2, false, true),    /**     * 临时节点：客户端会话失效或连接关闭后，该节点会被自动删除，且不能再临时节点下面创建子节点，否则报如下错（org.apache.zookeeper.KeeperException$NoChildrenForEphemeralsException: KeeperErrorCode = NoChildrenForEphemerals for /node/child）；     */    EPHEMERAL (1, true, false),    /**     * 临时顺序节点：基本特性与临时节点一致，创建节点的过程中，zookeeper会在其名字后自动追加一个单调增长的数字后缀，作为新的节点名；      */    EPHEMERAL_SEQUENTIAL (3, true, true);    private static final Logger LOG = LoggerFactory.getLogger(CreateMode.class);    private boolean ephemeral;    private boolean sequential;    private int flag;    CreateMode(int flag, boolean ephemeral, boolean sequential) {        this.flag = flag;        this.ephemeral = ephemeral;        this.sequential = sequential;    }    public boolean isEphemeral() {        return ephemeral;    }    public boolean isSequential() {        return sequential;    }    public int toFlag() {        return flag;    }    static public CreateMode fromFlag(int flag) throws KeeperException {        switch(flag) {        case 0: return CreateMode.PERSISTENT;        case 1: return CreateMode.EPHEMERAL;        case 2: return CreateMode.PERSISTENT_SEQUENTIAL;        case 3: return CreateMode.EPHEMERAL_SEQUENTIAL ;        default:            LOG.error("Received an invalid flag value to convert to a CreateMode");            throw new KeeperException.BadArgumentsException();        }    }}
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