com.bennavetta.aeneas.zookeeper.Servers.java Source code

Introduction

Here is the source code for com.bennavetta.aeneas.zookeeper.Servers.java

Source

/**
 * Copyright 2015 Benjamin Navetta
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.bennavetta.aeneas.zookeeper;

import com.google.common.base.Joiner;
import com.google.common.base.Preconditions;
import com.google.common.net.HostAndPort;

import java.util.Arrays;
import java.util.Collection;
import java.util.Map;
import java.util.stream.Collectors;

/**
 * Static utility methods related to ZooKeeper servers.
 */
public final class Servers {
    private Servers() {

    }

    /**
     * Generates suitable ZooKeeper configuration from a collection of server instances. The produced map is the parsed
     * equivalent of the {@code server.N} properties in ZooKeeper's dynamic configuration file.
     * @param servers the servers to include
     * @return a configuration chunk as a map
     */
    public static Map<String, String> toServerSpecification(ZkServer... servers) {
        Preconditions.checkNotNull(servers);
        return Arrays.stream(servers)
                .collect(Collectors.toMap(s -> "server." + s.getId(), ZkServer::toConnectionSpec));
    }

    /**
     * Generates suitable ZooKeeper configuration from a collection of server instances. The produced map is the parsed
     * equivalent of the {@code server.N} properties in ZooKeeper's dynamic configuration file.
     * @param servers the servers to include
     * @return a configuration chunk as a map
     */
    public static Map<String, String> toServerSpecification(Collection<ZkServer> servers) {
        Preconditions.checkNotNull(servers);
        return servers.stream().collect(Collectors.toMap(s -> "server." + s.getId(), ZkServer::toConnectionSpec));
    }

    /**
     * Builds a client connection string from several servers. The basic format is comma-separated host:port pairs.
     * The {@code zk://} protocol specifier can also be added, since some non-ZooKeeper applications require it (the
     * ZooKeeper client library does not). In addition, a chroot suffix can be added so that all paths on the client
     * are relative to it.
     * @param addProtocol {@code true} to add the {@code zk://} scheme
     * @param servers the servers the client can connect to
     * @param chroot the client's base path or {@code null}
     * @return a connection string
     */
    public static String toConnectionString(boolean addProtocol, Collection<ZkServer> servers, String chroot) {
        Preconditions.checkNotNull(servers);
        StringBuilder connection = new StringBuilder();

        if (addProtocol) {
            connection.append("zk://");
        }

        connection.append(servers.stream().map(ZkServer::toClientConnection).map(HostAndPort::toString)
                .collect(Collectors.joining(",")));

        if (chroot != null) {
            connection.append('/').append(chroot);
        }

        return connection.toString();
    }

    /**
     * Builds a client connection string from several servers. This is equivalent to
     * {@code toConnectionString(false, servers, null)}.
     * @param servers the servers the client can connect to
     * @return a connection string
     */
    public static String toConnectionString(Collection<ZkServer> servers) {
        return toConnectionString(false, servers, null);
    }
}