configserver/src/main/java/com/yahoo/vespa/config/server/zookeeper/SessionCounter.java


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30

// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.vespa.config.server.zookeeper;

import com.yahoo.config.provision.TenantName;
import com.yahoo.vespa.config.server.tenant.TenantRepository;
import com.yahoo.vespa.curator.Curator;

/**
 * A counter keeping track of session ids in an atomic fashion across multiple config servers.
 *
 * @author Ulf Lilleengen
 */
public class SessionCounter extends InitializedCounter {

    public SessionCounter(Curator curator, TenantName tenantName) {
        super(curator,
              TenantRepository.getTenantPath(tenantName).append("sessionCounter"),
              TenantRepository.getSessionsPath(tenantName));
    }

    /**
     * Atomically increment and return next session id.
     *
     * @return a new session id.
     */
    public long nextSessionId() {
        return counter.next();
    }

}