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A common base library for Apache Accumulo servers.
There is a newer version: 3.0.0
/*
 * 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.accumulo.server.replication;

import static java.util.Objects.requireNonNull;

import java.util.Map.Entry;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.common.collect.Maps;

/**
 *
 */
public class ReplicaSystemFactory {
  private static final Logger log = LoggerFactory.getLogger(ReplicaSystemFactory.class);

  /**
   * @param value
   *          {@link ReplicaSystem} implementation class name
   * @return A {@link ReplicaSystem} object from the given name
   */
  public ReplicaSystem get(String value) {
    final Entry entry = parseReplicaSystemConfiguration(value);

    try {
      Class clz = Class.forName(entry.getKey());

      if (ReplicaSystem.class.isAssignableFrom(clz)) {
        Object o = clz.newInstance();
        ReplicaSystem rs = (ReplicaSystem) o;
        rs.configure(entry.getValue());
        return rs;
      }

      throw new IllegalArgumentException("Class is not assignable to ReplicaSystem: " + entry.getKey());
    } catch (ClassNotFoundException | InstantiationException | IllegalAccessException e) {
      log.error("Error creating ReplicaSystem object", e);
      throw new IllegalArgumentException(e);
    }
  }

  /**
   * Parse the configuration value for a peer into its components: {@link ReplicaSystem} class name and configuration string.
   *
   * @param value
   *          The configuration value for a replication peer.
   * @return An entry where the set is the replica system name and the value is the configuration string.
   */
  public Entry parseReplicaSystemConfiguration(String value) {
    requireNonNull(value);

    int index = value.indexOf(',');
    if (-1 == index) {
      throw new IllegalArgumentException("Expected comma separator between replication system name and configuration");
    }

    String name = value.substring(0, index);
    String configuration = value.substring(index + 1);
    return Maps.immutableEntry(name, configuration);
  }

  /**
   * Generate the configuration value for a {@link ReplicaSystem} in the instance properties
   *
   * @param system
   *          The desired ReplicaSystem to use
   * @param configuration
   *          Configuration string for the desired ReplicaSystem
   * @return Value to set for peer configuration in the instance
   */
  public static String getPeerConfigurationValue(Class system, String configuration) {
    String systemName = system.getName() + ",";
    if (null == configuration) {
      return systemName;
    }

    return systemName + configuration;
  }
}