content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you 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 org.apache.distributedlog;
  
  import static com.google.common.base.Preconditions.checkArgument;
  import static com.google.common.base.Preconditions.checkNotNull;
  
  import java.net.URI;
  import org.apache.bookkeeper.stats.NullStatsLogger;
  import org.apache.bookkeeper.stats.StatsLogger;
  import org.apache.bookkeeper.zookeeper.RetryPolicy;
  import org.apache.distributedlog.ZooKeeperClient.Credentials;
  import org.apache.distributedlog.ZooKeeperClient.DigestCredentials;
  import org.apache.distributedlog.impl.BKNamespaceDriver;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  
  /**
   * Builder to build zookeeper client.
   */
  public class ZooKeeperClientBuilder {
  
      static final Logger LOG = LoggerFactory.getLogger(ZooKeeperClientBuilder.class);
  
      /**
       * Create a zookeeper client builder to build zookeeper clients.
       *
       * @return zookeeper client builder.
       */
      public static ZooKeeperClientBuilder newBuilder() {
          return new ZooKeeperClientBuilder();
      }
  
      // name
      private String name = "default";
      // sessionTimeoutMs
      private int sessionTimeoutMs = -1;
      // connectionTimeoutMs
      private int connectionTimeoutMs = -1;
      // zkServers
      private String zkServers = null;
      // retry policy
      private RetryPolicy retryPolicy = null;
      // stats logger
      private StatsLogger statsLogger = NullStatsLogger.INSTANCE;
      // retry executor thread count
      private int retryThreadCount = 1;
      // zookeeper access requestRateLimit limit
      private double requestRateLimit = 0;
      // Did call the zkAclId setter on the builder, used to ensure the setter is set.
      private boolean zkAclIdSet = false;
      private String zkAclId;
  
      // Cached ZooKeeper Client
      private ZooKeeperClient cachedClient = null;
  
      private ZooKeeperClientBuilder() {}
  
      /**
       * Set zookeeper client name.
       *
       * @param name zookeeper client name
       * @return zookeeper client builder
       */
      public synchronized ZooKeeperClientBuilder name(String name) {
          this.name = name;
          return this;
      }
  
      /**
       * Set zookeeper session timeout in milliseconds.
       *
       * @param sessionTimeoutMs
       *          session timeout in milliseconds.
       * @return zookeeper client builder.
       */
      public synchronized ZooKeeperClientBuilder sessionTimeoutMs(int sessionTimeoutMs) {
          this.sessionTimeoutMs = sessionTimeoutMs;
          if (this.connectionTimeoutMs <= 0) {
              this.connectionTimeoutMs = 2 * sessionTimeoutMs;
          }
          return this;
      }
  
      public synchronized ZooKeeperClientBuilder retryThreadCount(int retryThreadCount) {
          this.retryThreadCount = retryThreadCount;
          return this;
      }
  
      public synchronized ZooKeeperClientBuilder requestRateLimit(double requestRateLimit) {
          this.requestRateLimit = requestRateLimit;
          return this;
      }
  
      /**
       * Set zookeeper connection timeout in milliseconds.
       *
       * @param connectionTimeoutMs
       *          connection timeout ms.
       * @return builder
       */
      public synchronized ZooKeeperClientBuilder connectionTimeoutMs(int connectionTimeoutMs) {
          this.connectionTimeoutMs = connectionTimeoutMs;
          return this;
      }
  
      /**
       * Set ZooKeeper Connect String.
       *
       * @param zkServers
       *          zookeeper servers to connect.
       * @return builder
       */
      public synchronized ZooKeeperClientBuilder zkServers(String zkServers) {
          this.zkServers = zkServers;
          return this;
      }
  
      /**
       * Set DistributedLog URI.
       *
       * @param uri
       *          distributedlog uri.
       * @return builder.
       */
      public synchronized ZooKeeperClientBuilder uri(URI uri) {
          this.zkServers = BKNamespaceDriver.getZKServersFromDLUri(uri);
          return this;
      }
  
      /**
       * Build zookeeper client using existing <i>zkc</i> client.
       *
       * @param zkc
       *          zookeeper client.
       * @return builder
       */
      public synchronized ZooKeeperClientBuilder zkc(ZooKeeperClient zkc) {
          this.cachedClient = zkc;
          return this;
      }
  
      /**
       * Build zookeeper client with given retry policy <i>retryPolicy</i>.
       *
       * @param retryPolicy
       *          retry policy
       * @return builder
       */
      public synchronized ZooKeeperClientBuilder retryPolicy(RetryPolicy retryPolicy) {
          this.retryPolicy = retryPolicy;
          return this;
      }
  
      /**
       * Build zookeeper client with given stats logger <i>statsLogger</i>.
       *
       * @param statsLogger
       *          stats logger to expose zookeeper stats
       * @return builder
       */
      public synchronized ZooKeeperClientBuilder statsLogger(StatsLogger statsLogger) {
          this.statsLogger = statsLogger;
          return this;
      }
  
      /**
       * * Build zookeeper client with given zk acl digest id <i>zkAclId</i>.
       */
      public synchronized ZooKeeperClientBuilder zkAclId(String zkAclId) {
          this.zkAclIdSet = true;
          this.zkAclId = zkAclId;
          return this;
      }
  
      private void validateParameters() {
          checkNotNull(zkServers, "No zk servers provided.");
          checkArgument(connectionTimeoutMs > 0,
                  "Invalid connection timeout : %d", connectionTimeoutMs);
          checkArgument(sessionTimeoutMs > 0,
                  "Invalid session timeout : %d", sessionTimeoutMs);
          checkNotNull(statsLogger, "No stats logger provided.");
          checkArgument(zkAclIdSet, "Zookeeper acl id not set.");
      }
  
      /**
       * Build a zookeeper client.
       *
       * @return zookeeper client.
       */
      public synchronized ZooKeeperClient build() {
          if (null == cachedClient) {
              cachedClient = buildClient();
          }
          return cachedClient;
      }
  
      private ZooKeeperClient buildClient() {
          validateParameters();
  
          Credentials credentials = Credentials.NONE;
          if (null != zkAclId) {
              credentials = new DigestCredentials(zkAclId, zkAclId);
          }
  
          return new ZooKeeperClient(
                  name,
                  sessionTimeoutMs,
                  connectionTimeoutMs,
                  zkServers,
                  retryPolicy,
                  statsLogger,
                  retryThreadCount,
                  requestRateLimit,
                  credentials
          );
      }
  }
  