/*
 * 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.giraph.conf;

import org.apache.giraph.aggregators.AggregatorWriter;
import org.apache.giraph.aggregators.TextAggregatorWriter;
import org.apache.giraph.bsp.BspOutputFormat;
import org.apache.giraph.bsp.checkpoints.CheckpointSupportedChecker;
import org.apache.giraph.bsp.checkpoints.DefaultCheckpointSupportedChecker;
import org.apache.giraph.combiner.MessageCombiner;
import org.apache.giraph.comm.messages.InMemoryMessageStoreFactory;
import org.apache.giraph.comm.messages.MessageEncodeAndStoreType;
import org.apache.giraph.comm.messages.MessageStoreFactory;
import org.apache.giraph.edge.ByteArrayEdges;
import org.apache.giraph.edge.EdgeStoreFactory;
import org.apache.giraph.edge.InMemoryEdgeStoreFactory;
import org.apache.giraph.edge.OutEdges;
import org.apache.giraph.factories.ComputationFactory;
import org.apache.giraph.factories.DefaultComputationFactory;
import org.apache.giraph.factories.DefaultEdgeValueFactory;
import org.apache.giraph.factories.DefaultMessageValueFactory;
import org.apache.giraph.factories.DefaultVertexIdFactory;
import org.apache.giraph.factories.DefaultVertexValueFactory;
import org.apache.giraph.factories.EdgeValueFactory;
import org.apache.giraph.factories.MessageValueFactory;
import org.apache.giraph.factories.VertexIdFactory;
import org.apache.giraph.factories.VertexValueFactory;
import org.apache.giraph.graph.Computation;
import org.apache.giraph.graph.DefaultVertex;
import org.apache.giraph.graph.DefaultVertexResolver;
import org.apache.giraph.graph.DefaultVertexValueCombiner;
import org.apache.giraph.graph.Language;
import org.apache.giraph.graph.MapperObserver;
import org.apache.giraph.graph.Vertex;
import org.apache.giraph.graph.VertexResolver;
import org.apache.giraph.graph.VertexValueCombiner;
import org.apache.giraph.io.EdgeInputFormat;
import org.apache.giraph.io.EdgeOutputFormat;
import org.apache.giraph.io.MappingInputFormat;
import org.apache.giraph.io.VertexInputFormat;
import org.apache.giraph.io.VertexOutputFormat;
import org.apache.giraph.io.filters.DefaultEdgeInputFilter;
import org.apache.giraph.io.filters.DefaultVertexInputFilter;
import org.apache.giraph.io.filters.EdgeInputFilter;
import org.apache.giraph.io.filters.VertexInputFilter;
import org.apache.giraph.job.DefaultGiraphJobRetryChecker;
import org.apache.giraph.job.DefaultJobObserver;
import org.apache.giraph.job.DefaultJobProgressTrackerService;
import org.apache.giraph.job.GiraphJobObserver;
import org.apache.giraph.job.GiraphJobRetryChecker;
import org.apache.giraph.job.HaltApplicationUtils;
import org.apache.giraph.job.JobProgressTrackerService;
import org.apache.giraph.mapping.MappingStore;
import org.apache.giraph.mapping.MappingStoreOps;
import org.apache.giraph.mapping.translate.TranslateEdge;
import org.apache.giraph.master.DefaultMasterCompute;
import org.apache.giraph.master.MasterCompute;
import org.apache.giraph.master.MasterObserver;
import org.apache.giraph.ooc.persistence.OutOfCoreDataAccessor;
import org.apache.giraph.ooc.persistence.LocalDiskDataAccessor;
import org.apache.giraph.ooc.policy.OutOfCoreOracle;
import org.apache.giraph.ooc.policy.ThresholdBasedOracle;
import org.apache.giraph.partition.GraphPartitionerFactory;
import org.apache.giraph.partition.HashPartitionerFactory;
import org.apache.giraph.partition.Partition;
import org.apache.giraph.partition.SimplePartition;
import org.apache.giraph.worker.DefaultWorkerContext;
import org.apache.giraph.worker.WorkerContext;
import org.apache.giraph.worker.WorkerObserver;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.mapreduce.OutputFormat;

import static java.util.concurrent.TimeUnit.MINUTES;
import static java.util.concurrent.TimeUnit.SECONDS;

/**
 * Constants used all over Giraph for configuration.
 */
// CHECKSTYLE: stop InterfaceIsTypeCheck
public interface GiraphConstants {
  /** 1KB in bytes */
  int ONE_KB = 1024;
  /** 1MB in bytes */
  int ONE_MB = 1024 * 1024;

  /** Mapping related information */
  ClassConfOption<MappingStore> MAPPING_STORE_CLASS =
      ClassConfOption.create("giraph.mappingStoreClass", null,
          MappingStore.class, "MappingStore Class");

  /** Class to use for performing read operations on mapping store */
  ClassConfOption<MappingStoreOps> MAPPING_STORE_OPS_CLASS =
      ClassConfOption.create("giraph.mappingStoreOpsClass", null,
          MappingStoreOps.class, "MappingStoreOps class");

  /** Upper value of LongByteMappingStore */
  IntConfOption LB_MAPPINGSTORE_UPPER =
      new IntConfOption("giraph.lbMappingStoreUpper", -1,
          "'upper' value used by lbmappingstore");
  /** Lower value of LongByteMappingStore */
  IntConfOption LB_MAPPINGSTORE_LOWER =
      new IntConfOption("giraph.lbMappingStoreLower", -1,
          "'lower' value used by lbMappingstore");
  /** Class used to conduct expensive edge translation during vertex input */
  ClassConfOption EDGE_TRANSLATION_CLASS =
      ClassConfOption.create("giraph.edgeTranslationClass", null,
          TranslateEdge.class, "Class used to conduct expensive edge " +
              "translation during vertex input phase");

  /** Computation class - required */
  ClassConfOption<Computation> COMPUTATION_CLASS =
      ClassConfOption.create("giraph.computationClass", null,
          Computation.class, "Computation class - required");
  /** Computation factory class - optional */
  ClassConfOption<ComputationFactory> COMPUTATION_FACTORY_CLASS =
      ClassConfOption.create("giraph.computation.factory.class",
          DefaultComputationFactory.class, ComputationFactory.class,
          "Computation factory class - optional");

  /** TypesHolder, used if Computation not set - optional */
  ClassConfOption<TypesHolder> TYPES_HOLDER_CLASS =
      ClassConfOption.create("giraph.typesHolder", null,
          TypesHolder.class,
          "TypesHolder, used if Computation not set - optional");

  /** Edge Store Factory */
  ClassConfOption<EdgeStoreFactory> EDGE_STORE_FACTORY_CLASS =
      ClassConfOption.create("giraph.edgeStoreFactoryClass",
          InMemoryEdgeStoreFactory.class,
          EdgeStoreFactory.class,
          "Edge Store Factory class to use for creating edgeStore");

  /** Message Store Factory */
  ClassConfOption<MessageStoreFactory> MESSAGE_STORE_FACTORY_CLASS =
      ClassConfOption.create("giraph.messageStoreFactoryClass",
          InMemoryMessageStoreFactory.class,
          MessageStoreFactory.class,
          "Message Store Factory Class that is to be used");

  /** Language user's graph types are implemented in */
  PerGraphTypeEnumConfOption<Language> GRAPH_TYPE_LANGUAGES =
      PerGraphTypeEnumConfOption.create("giraph.types.language",
          Language.class, Language.JAVA,
          "Language user graph types (IVEMM) are implemented in");

  /** Whether user graph types need wrappers */
  PerGraphTypeBooleanConfOption GRAPH_TYPES_NEEDS_WRAPPERS =
      new PerGraphTypeBooleanConfOption("giraph.jython.type.wrappers",
          false, "Whether user graph types (IVEMM) need Jython wrappers");

  /** Vertex id factory class - optional */
  ClassConfOption<VertexIdFactory> VERTEX_ID_FACTORY_CLASS =
      ClassConfOption.create("giraph.vertexIdFactoryClass",
          DefaultVertexIdFactory.class, VertexIdFactory.class,
          "Vertex ID factory class - optional");
  /** Vertex value factory class - optional */
  ClassConfOption<VertexValueFactory> VERTEX_VALUE_FACTORY_CLASS =
      ClassConfOption.create("giraph.vertexValueFactoryClass",
          DefaultVertexValueFactory.class, VertexValueFactory.class,
          "Vertex value factory class - optional");
  /** Edge value factory class - optional */
  ClassConfOption<EdgeValueFactory> EDGE_VALUE_FACTORY_CLASS =
      ClassConfOption.create("giraph.edgeValueFactoryClass",
          DefaultEdgeValueFactory.class, EdgeValueFactory.class,
          "Edge value factory class - optional");
  /** Outgoing message value factory class - optional */
  ClassConfOption<MessageValueFactory>
  OUTGOING_MESSAGE_VALUE_FACTORY_CLASS =
      ClassConfOption.create("giraph.outgoingMessageValueFactoryClass",
          DefaultMessageValueFactory.class, MessageValueFactory.class,
          "Outgoing message value factory class - optional");

  /** Vertex edges class - optional */
  ClassConfOption<OutEdges> VERTEX_EDGES_CLASS =
      ClassConfOption.create("giraph.outEdgesClass", ByteArrayEdges.class,
          OutEdges.class, "Vertex edges class - optional");
  /** Vertex edges class to be used during edge input only - optional */
  ClassConfOption<OutEdges> INPUT_VERTEX_EDGES_CLASS =
      ClassConfOption.create("giraph.inputOutEdgesClass",
          ByteArrayEdges.class, OutEdges.class,
          "Vertex edges class to be used during edge input only - optional");

  /** Class for Master - optional */
  ClassConfOption<MasterCompute> MASTER_COMPUTE_CLASS =
      ClassConfOption.create("giraph.masterComputeClass",
          DefaultMasterCompute.class, MasterCompute.class,
          "Class for Master - optional");
  /** Classes for Master Observer - optional */
  ClassConfOption<MasterObserver> MASTER_OBSERVER_CLASSES =
      ClassConfOption.create("giraph.master.observers",
          null, MasterObserver.class, "Classes for Master Observer - optional");
  /** Classes for Worker Observer - optional */
  ClassConfOption<WorkerObserver> WORKER_OBSERVER_CLASSES =
      ClassConfOption.create("giraph.worker.observers", null,
          WorkerObserver.class, "Classes for Worker Observer - optional");
  /** Classes for Mapper Observer - optional */
  ClassConfOption<MapperObserver> MAPPER_OBSERVER_CLASSES =
      ClassConfOption.create("giraph.mapper.observers", null,
          MapperObserver.class, "Classes for Mapper Observer - optional");
  /** Message combiner class - optional */
  ClassConfOption<MessageCombiner> MESSAGE_COMBINER_CLASS =
      ClassConfOption.create("giraph.messageCombinerClass", null,
          MessageCombiner.class, "Message combiner class - optional");
  /** Vertex resolver class - optional */
  ClassConfOption<VertexResolver> VERTEX_RESOLVER_CLASS =
      ClassConfOption.create("giraph.vertexResolverClass",
          DefaultVertexResolver.class, VertexResolver.class,
          "Vertex resolver class - optional");
  /** Vertex value combiner class - optional */
  ClassConfOption<VertexValueCombiner> VERTEX_VALUE_COMBINER_CLASS =
      ClassConfOption.create("giraph.vertexValueCombinerClass",
          DefaultVertexValueCombiner.class, VertexValueCombiner.class,
          "Vertex value combiner class - optional");

  /** Which language computation is implemented in */
  EnumConfOption<Language> COMPUTATION_LANGUAGE =
      EnumConfOption.create("giraph.computation.language",
          Language.class, Language.JAVA,
          "Which language computation is implemented in");

  /**
   * Option of whether to create vertexes that were not existent before but
   * received messages
   */
  BooleanConfOption RESOLVER_CREATE_VERTEX_ON_MSGS =
      new BooleanConfOption("giraph.vertex.resolver.create.on.msgs", true,
          "Option of whether to create vertexes that were not existent " +
          "before but received messages");
  /** Graph partitioner factory class - optional */
  ClassConfOption<GraphPartitionerFactory> GRAPH_PARTITIONER_FACTORY_CLASS =
      ClassConfOption.create("giraph.graphPartitionerFactoryClass",
          HashPartitionerFactory.class, GraphPartitionerFactory.class,
          "Graph partitioner factory class - optional");

  /** Observer class to watch over job status - optional */
  ClassConfOption<GiraphJobObserver> JOB_OBSERVER_CLASS =
      ClassConfOption.create("giraph.jobObserverClass",
          DefaultJobObserver.class, GiraphJobObserver.class,
          "Observer class to watch over job status - optional");

  /** Observer class to watch over job status - optional */
  ClassConfOption<GiraphJobRetryChecker> JOB_RETRY_CHECKER_CLASS =
      ClassConfOption.create("giraph.jobRetryCheckerClass",
          DefaultGiraphJobRetryChecker.class, GiraphJobRetryChecker.class,
          "Class which decides whether a failed job should be retried - " +
              "optional");

  /**
   * Maximum allowed time for job to run after getting all resources before it
   * will be killed, in milliseconds (-1 if it has no limit)
   */
  LongConfOption MAX_ALLOWED_JOB_TIME_MS =
      new LongConfOption("giraph.maxAllowedJobTimeMilliseconds", -1,
          "Maximum allowed time for job to run after getting all resources " +
              "before it will be killed, in milliseconds " +
              "(-1 if it has no limit)");

  // At least one of the input format classes is required.
  /** VertexInputFormat class */
  ClassConfOption<VertexInputFormat> VERTEX_INPUT_FORMAT_CLASS =
      ClassConfOption.create("giraph.vertexInputFormatClass", null,
          VertexInputFormat.class, "VertexInputFormat class (at least " +
          "one of the input format classes is required)");
  /** EdgeInputFormat class */
  ClassConfOption<EdgeInputFormat> EDGE_INPUT_FORMAT_CLASS =
      ClassConfOption.create("giraph.edgeInputFormatClass", null,
          EdgeInputFormat.class, "EdgeInputFormat class");
  /** MappingInputFormat class */
  ClassConfOption<MappingInputFormat> MAPPING_INPUT_FORMAT_CLASS =
      ClassConfOption.create("giraph.mappingInputFormatClass", null,
          MappingInputFormat.class, "MappingInputFormat class");

  /** EdgeInputFilter class */
  ClassConfOption<EdgeInputFilter> EDGE_INPUT_FILTER_CLASS =
      ClassConfOption.create("giraph.edgeInputFilterClass",
          DefaultEdgeInputFilter.class, EdgeInputFilter.class,
          "EdgeInputFilter class");
  /** VertexInputFilter class */
  ClassConfOption<VertexInputFilter> VERTEX_INPUT_FILTER_CLASS =
      ClassConfOption.create("giraph.vertexInputFilterClass",
          DefaultVertexInputFilter.class, VertexInputFilter.class,
          "VertexInputFilter class");
  /** Vertex class */
  ClassConfOption<Vertex> VERTEX_CLASS =
      ClassConfOption.create("giraph.vertexClass",
          DefaultVertex.class, Vertex.class,
          "Vertex class");
  /** VertexOutputFormat class */
  ClassConfOption<VertexOutputFormat> VERTEX_OUTPUT_FORMAT_CLASS =
      ClassConfOption.create("giraph.vertexOutputFormatClass", null,
          VertexOutputFormat.class, "VertexOutputFormat class");
  /** EdgeOutputFormat sub-directory */
  StrConfOption VERTEX_OUTPUT_FORMAT_SUBDIR =
    new StrConfOption("giraph.vertex.output.subdir", "",
                      "VertexOutputFormat sub-directory");
  /** EdgeOutputFormat class */
  ClassConfOption<EdgeOutputFormat> EDGE_OUTPUT_FORMAT_CLASS =
      ClassConfOption.create("giraph.edgeOutputFormatClass", null,
          EdgeOutputFormat.class, "EdgeOutputFormat class");
  /** EdgeOutputFormat sub-directory */
  StrConfOption EDGE_OUTPUT_FORMAT_SUBDIR =
    new StrConfOption("giraph.edge.output.subdir", "",
                      "EdgeOutputFormat sub-directory");

  /** GiraphTextOuputFormat Separator */
  StrConfOption GIRAPH_TEXT_OUTPUT_FORMAT_SEPARATOR =
    new StrConfOption("giraph.textoutputformat.separator", "\t",
                      "GiraphTextOuputFormat Separator");
  /** Reverse values in the output */
  BooleanConfOption GIRAPH_TEXT_OUTPUT_FORMAT_REVERSE =
      new BooleanConfOption("giraph.textoutputformat.reverse", false,
                            "Reverse values in the output");

  /**
   * If you use this option, instead of having saving vertices in the end of
   * application, saveVertex will be called right after each vertex.compute()
   * is called.
   * NOTE: This feature doesn't work well with checkpointing - if you restart
   * from a checkpoint you won't have any output from previous supersteps.
   */
  BooleanConfOption DO_OUTPUT_DURING_COMPUTATION =
      new BooleanConfOption("giraph.doOutputDuringComputation", false,
          "If you use this option, instead of having saving vertices in the " +
          "end of application, saveVertex will be called right after each " +
          "vertex.compute() is called." +
          "NOTE: This feature doesn't work well with checkpointing - if you " +
          "restart from a checkpoint you won't have any ouptut from previous " +
          "supresteps.");
  /**
   * Vertex output format thread-safe - if your VertexOutputFormat allows
   * several vertexWriters to be created and written to in parallel,
   * you should set this to true.
   */
  BooleanConfOption VERTEX_OUTPUT_FORMAT_THREAD_SAFE =
      new BooleanConfOption("giraph.vertexOutputFormatThreadSafe", false,
          "Vertex output format thread-safe - if your VertexOutputFormat " +
          "allows several vertexWriters to be created and written to in " +
          "parallel, you should set this to true.");
  /** Number of threads for writing output in the end of the application */
  IntConfOption NUM_OUTPUT_THREADS =
      new IntConfOption("giraph.numOutputThreads", 1,
          "Number of threads for writing output in the end of the application");

  /** conf key for comma-separated list of jars to export to YARN workers */
  StrConfOption GIRAPH_YARN_LIBJARS =
    new StrConfOption("giraph.yarn.libjars", "",
        "conf key for comma-separated list of jars to export to YARN workers");
  /** Name of the XML file that will export our Configuration to YARN workers */
  String GIRAPH_YARN_CONF_FILE = "giraph-conf.xml";
  /** Giraph default heap size for all tasks when running on YARN profile */
  int GIRAPH_YARN_TASK_HEAP_MB_DEFAULT = 1024;
  /** Name of Giraph property for user-configurable heap memory per worker */
  IntConfOption GIRAPH_YARN_TASK_HEAP_MB = new IntConfOption(
    "giraph.yarn.task.heap.mb", GIRAPH_YARN_TASK_HEAP_MB_DEFAULT,
    "Name of Giraph property for user-configurable heap memory per worker");
  /** Default priority level in YARN for our task containers */
  int GIRAPH_YARN_PRIORITY = 10;
  /** Is this a pure YARN job (i.e. no MapReduce layer managing Giraph tasks) */
  BooleanConfOption IS_PURE_YARN_JOB =
    new BooleanConfOption("giraph.pure.yarn.job", false,
        "Is this a pure YARN job (i.e. no MapReduce layer managing Giraph " +
        "tasks)");

  /** Vertex index class */
  ClassConfOption<WritableComparable> VERTEX_ID_CLASS =
      ClassConfOption.create("giraph.vertexIdClass", null,
          WritableComparable.class, "Vertex index class");
  /** Vertex value class */
  ClassConfOption<Writable> VERTEX_VALUE_CLASS =
      ClassConfOption.create("giraph.vertexValueClass", null, Writable.class,
          "Vertex value class");
  /** Edge value class */
  ClassConfOption<Writable> EDGE_VALUE_CLASS =
      ClassConfOption.create("giraph.edgeValueClass", null, Writable.class,
          "Edge value class");
  /** Outgoing message value class */
  ClassConfOption<Writable> OUTGOING_MESSAGE_VALUE_CLASS =
      ClassConfOption.create("giraph.outgoingMessageValueClass", null,
          Writable.class, "Outgoing message value class");
  /** Worker context class */
  ClassConfOption<WorkerContext> WORKER_CONTEXT_CLASS =
      ClassConfOption.create("giraph.workerContextClass",
          DefaultWorkerContext.class, WorkerContext.class,
          "Worker contextclass");
  /** AggregatorWriter class - optional */
  ClassConfOption<AggregatorWriter> AGGREGATOR_WRITER_CLASS =
      ClassConfOption.create("giraph.aggregatorWriterClass",
          TextAggregatorWriter.class, AggregatorWriter.class,
          "AggregatorWriter class - optional");

  /** Partition class - optional */
  ClassConfOption<Partition> PARTITION_CLASS =
      ClassConfOption.create("giraph.partitionClass", SimplePartition.class,
          Partition.class, "Partition class - optional");

  /**
   * Minimum number of simultaneous workers before this job can run (int)
   */
  String MIN_WORKERS = "giraph.minWorkers";
  /**
   * Maximum number of simultaneous worker tasks started by this job (int).
   */
  String MAX_WORKERS = "giraph.maxWorkers";

  /**
   * Separate the workers and the master tasks.  This is required
   * to support dynamic recovery. (boolean)
   */
  BooleanConfOption SPLIT_MASTER_WORKER =
      new BooleanConfOption("giraph.SplitMasterWorker", true,
          "Separate the workers and the master tasks.  This is required to " +
          "support dynamic recovery. (boolean)");

  /** Indicates whether this job is run in an internal unit test */
  BooleanConfOption LOCAL_TEST_MODE =
      new BooleanConfOption("giraph.localTestMode", false,
          "Indicates whether this job is run in an internal unit test");

  /** Override the Hadoop log level and set the desired log level. */
  StrConfOption LOG_LEVEL = new StrConfOption("giraph.logLevel", "info",
      "Override the Hadoop log level and set the desired log level.");

  /** Use thread level debugging? */
  BooleanConfOption LOG_THREAD_LAYOUT =
      new BooleanConfOption("giraph.logThreadLayout", false,
          "Use thread level debugging?");

  /** Configuration key to enable jmap printing */
  BooleanConfOption JMAP_ENABLE =
      new BooleanConfOption("giraph.jmap.histo.enable", false,
          "Configuration key to enable jmap printing");

  /** Configuration key for msec to sleep between calls */
  IntConfOption JMAP_SLEEP_MILLIS =
      new IntConfOption("giraph.jmap.histo.msec", SECONDS.toMillis(30),
          "Configuration key for msec to sleep between calls");

  /** Configuration key for how many lines to print */
  IntConfOption JMAP_PRINT_LINES =
      new IntConfOption("giraph.jmap.histo.print_lines", 30,
          "Configuration key for how many lines to print");

  /**
   * Configuration key for printing live objects only
   * This option will trigger Full GC for every jmap dump
   * and so can significantly hinder performance.
   */
  BooleanConfOption JMAP_LIVE_ONLY =
      new BooleanConfOption("giraph.jmap.histo.live", false,
          "Only print live objects in jmap?");

  /**
   * Option used by ReactiveJMapHistoDumper to check for an imminent
   * OOM in worker or master process
   */
  IntConfOption MIN_FREE_MBS_ON_HEAP =
      new IntConfOption("giraph.heap.minFreeMb", 128, "Option used by " +
          "worker and master observers to check for imminent OOM exception");
  /**
   * Option can be used to enable reactively dumping jmap histo when
   * OOM is imminent
   */
  BooleanConfOption REACTIVE_JMAP_ENABLE =
      new BooleanConfOption("giraph.heap.enableReactiveJmapDumping", false,
          "Option to enable dumping jmap histogram reactively based on " +
              "free memory on heap");

  /**
   * Minimum percent of the maximum number of workers that have responded
   * in order to continue progressing. (float)
   */
  FloatConfOption MIN_PERCENT_RESPONDED =
      new FloatConfOption("giraph.minPercentResponded", 100.0f,
          "Minimum percent of the maximum number of workers that have " +
          "responded in order to continue progressing. (float)");

  /** Enable the Metrics system */
  BooleanConfOption METRICS_ENABLE =
      new BooleanConfOption("giraph.metrics.enable", false,
          "Enable the Metrics system");

  /** Directory in HDFS to write master metrics to, instead of stderr */
  StrConfOption METRICS_DIRECTORY =
      new StrConfOption("giraph.metrics.directory", "",
          "Directory in HDFS to write master metrics to, instead of stderr");

  /**
   *  ZooKeeper comma-separated list (if not set,
   *  will start up ZooKeeper locally). Consider that after locally-starting
   *  zookeeper, this parameter will updated the configuration with the corrent
   *  configuration value.
   */
  StrConfOption ZOOKEEPER_LIST =
      new StrConfOption("giraph.zkList", "",
          "ZooKeeper comma-separated list (if not set, will start up " +
          "ZooKeeper locally). Consider that after locally-starting " +
          "zookeeper, this parameter will updated the configuration with " +
          "the corrent configuration value.");

  /**
   * Zookeeper List will always hold a value during the computation while
   * this option provides information regarding whether the zookeeper was
   * internally started or externally provided.
   */
  BooleanConfOption ZOOKEEPER_IS_EXTERNAL =
    new BooleanConfOption("giraph.zkIsExternal", true,
                          "Zookeeper List will always hold a value during " +
                          "the computation while this option provides " +
                          "information regarding whether the zookeeper was " +
                          "internally started or externally provided.");

  /** ZooKeeper session millisecond timeout */
  IntConfOption ZOOKEEPER_SESSION_TIMEOUT =
      new IntConfOption("giraph.zkSessionMsecTimeout", MINUTES.toMillis(1),
          "ZooKeeper session millisecond timeout");

  /** Polling interval to check for the ZooKeeper server data */
  IntConfOption ZOOKEEPER_SERVERLIST_POLL_MSECS =
      new IntConfOption("giraph.zkServerlistPollMsecs", SECONDS.toMillis(3),
          "Polling interval to check for the ZooKeeper server data");

  /** ZooKeeper port to use */
  IntConfOption ZOOKEEPER_SERVER_PORT =
      new IntConfOption("giraph.zkServerPort", 22181, "ZooKeeper port to use");

  /** Local ZooKeeper directory to use */
  String ZOOKEEPER_DIR = "giraph.zkDir";

  /** Max attempts for handling ZooKeeper connection loss */
  IntConfOption ZOOKEEPER_OPS_MAX_ATTEMPTS =
      new IntConfOption("giraph.zkOpsMaxAttempts", 3,
          "Max attempts for handling ZooKeeper connection loss");

  /**
   * Msecs to wait before retrying a failed ZooKeeper op due to connection loss.
   */
  IntConfOption ZOOKEEPER_OPS_RETRY_WAIT_MSECS =
      new IntConfOption("giraph.zkOpsRetryWaitMsecs", SECONDS.toMillis(5),
          "Msecs to wait before retrying a failed ZooKeeper op due to " +
          "connection loss.");

  /** TCP backlog (defaults to number of workers) */
  IntConfOption TCP_BACKLOG = new IntConfOption("giraph.tcpBacklog", 1,
      "TCP backlog (defaults to number of workers)");

  /** Use netty pooled memory buffer allocator */
  BooleanConfOption NETTY_USE_POOLED_ALLOCATOR = new BooleanConfOption(
      "giraph.useNettyPooledAllocator", false, "Should netty use pooled " +
      "memory allocator?");

  /** Use direct memory buffers in netty */
  BooleanConfOption NETTY_USE_DIRECT_MEMORY = new BooleanConfOption(
      "giraph.useNettyDirectMemory", false, "Should netty use direct " +
      "memory buffers");

  /** How big to make the encoder buffer? */
  IntConfOption NETTY_REQUEST_ENCODER_BUFFER_SIZE =
      new IntConfOption("giraph.nettyRequestEncoderBufferSize", 32 * ONE_KB,
          "How big to make the encoder buffer?");

  /** Netty client threads */
  IntConfOption NETTY_CLIENT_THREADS =
      new IntConfOption("giraph.nettyClientThreads", 4, "Netty client threads");

  /** Netty server threads */
  IntConfOption NETTY_SERVER_THREADS =
      new IntConfOption("giraph.nettyServerThreads", 16,
          "Netty server threads");

  /** Use the execution handler in netty on the client? */
  BooleanConfOption NETTY_CLIENT_USE_EXECUTION_HANDLER =
      new BooleanConfOption("giraph.nettyClientUseExecutionHandler", true,
          "Use the execution handler in netty on the client?");

  /** Netty client execution threads (execution handler) */
  IntConfOption NETTY_CLIENT_EXECUTION_THREADS =
      new IntConfOption("giraph.nettyClientExecutionThreads", 8,
          "Netty client execution threads (execution handler)");

  /** Where to place the netty client execution handle? */
  StrConfOption NETTY_CLIENT_EXECUTION_AFTER_HANDLER =
      new StrConfOption("giraph.nettyClientExecutionAfterHandler",
          "request-encoder",
          "Where to place the netty client execution handle?");

  /** Use the execution handler in netty on the server? */
  BooleanConfOption NETTY_SERVER_USE_EXECUTION_HANDLER =
      new BooleanConfOption("giraph.nettyServerUseExecutionHandler", true,
          "Use the execution handler in netty on the server?");

  /** Netty server execution threads (execution handler) */
  IntConfOption NETTY_SERVER_EXECUTION_THREADS =
      new IntConfOption("giraph.nettyServerExecutionThreads", 8,
          "Netty server execution threads (execution handler)");

  /** Where to place the netty server execution handle? */
  StrConfOption NETTY_SERVER_EXECUTION_AFTER_HANDLER =
      new StrConfOption("giraph.nettyServerExecutionAfterHandler",
          "requestFrameDecoder",
          "Where to place the netty server execution handle?");

  /** Netty simulate a first request closed */
  BooleanConfOption NETTY_SIMULATE_FIRST_REQUEST_CLOSED =
      new BooleanConfOption("giraph.nettySimulateFirstRequestClosed", false,
          "Netty simulate a first request closed");

  /** Netty simulate a first response failed */
  BooleanConfOption NETTY_SIMULATE_FIRST_RESPONSE_FAILED =
      new BooleanConfOption("giraph.nettySimulateFirstResponseFailed", false,
          "Netty simulate a first response failed");

  /** Netty - set which compression to use */
  StrConfOption NETTY_COMPRESSION_ALGORITHM =
      new StrConfOption("giraph.nettyCompressionAlgorithm", "",
          "Which compression algorithm to use in netty");

  /**
   * Whether netty should pro-actively read requests and feed them to its
   * processing pipeline
   */
  BooleanConfOption NETTY_AUTO_READ =
      new BooleanConfOption("giraph.nettyAutoRead", true,
          "Whether netty should pro-actively read requests and feed them to " +
              "its processing pipeline");

  /** Max resolve address attempts */
  IntConfOption MAX_RESOLVE_ADDRESS_ATTEMPTS =
      new IntConfOption("giraph.maxResolveAddressAttempts", 5,
          "Max resolve address attempts");

  /** Msecs to wait between waiting for all requests to finish */
  IntConfOption WAITING_REQUEST_MSECS =
      new IntConfOption("giraph.waitingRequestMsecs", SECONDS.toMillis(15),
          "Msecs to wait between waiting for all requests to finish");

  /** Millseconds to wait for an event before continuing */
  IntConfOption EVENT_WAIT_MSECS =
      new IntConfOption("giraph.eventWaitMsecs", SECONDS.toMillis(30),
          "Millseconds to wait for an event before continuing");

  /**
   * Maximum milliseconds to wait before giving up trying to get the minimum
   * number of workers before a superstep (int).
   */
  IntConfOption MAX_MASTER_SUPERSTEP_WAIT_MSECS =
      new IntConfOption("giraph.maxMasterSuperstepWaitMsecs",
          MINUTES.toMillis(10),
          "Maximum milliseconds to wait before giving up trying to get the " +
          "minimum number of workers before a superstep (int).");

  /** Milliseconds for a request to complete (or else resend) */
  IntConfOption MAX_REQUEST_MILLISECONDS =
      new IntConfOption("giraph.maxRequestMilliseconds", MINUTES.toMillis(10),
          "Milliseconds for a request to complete (or else resend)");

  /** Netty max connection failures */
  IntConfOption NETTY_MAX_CONNECTION_FAILURES =
      new IntConfOption("giraph.nettyMaxConnectionFailures", 1000,
          "Netty max connection failures");

  /** How long to wait before trying to reconnect failed connections */
  IntConfOption WAIT_TIME_BETWEEN_CONNECTION_RETRIES_MS =
      new IntConfOption("giraph.waitTimeBetweenConnectionRetriesMs", 500,
          "");

  /** Initial port to start using for the IPC communication */
  IntConfOption IPC_INITIAL_PORT =
      new IntConfOption("giraph.ipcInitialPort", 30000,
          "Initial port to start using for the IPC communication");

  /** Maximum bind attempts for different IPC ports */
  IntConfOption MAX_IPC_PORT_BIND_ATTEMPTS =
      new IntConfOption("giraph.maxIpcPortBindAttempts", 20,
          "Maximum bind attempts for different IPC ports");
  /**
   * Fail first IPC port binding attempt, simulate binding failure
   * on real grid testing
   */
  BooleanConfOption FAIL_FIRST_IPC_PORT_BIND_ATTEMPT =
      new BooleanConfOption("giraph.failFirstIpcPortBindAttempt", false,
          "Fail first IPC port binding attempt, simulate binding failure " +
          "on real grid testing");

  /** Client send buffer size */
  IntConfOption CLIENT_SEND_BUFFER_SIZE =
      new IntConfOption("giraph.clientSendBufferSize", 512 * ONE_KB,
          "Client send buffer size");

  /** Client receive buffer size */
  IntConfOption CLIENT_RECEIVE_BUFFER_SIZE =
      new IntConfOption("giraph.clientReceiveBufferSize", 32 * ONE_KB,
          "Client receive buffer size");

  /** Server send buffer size */
  IntConfOption SERVER_SEND_BUFFER_SIZE =
      new IntConfOption("giraph.serverSendBufferSize", 32 * ONE_KB,
          "Server send buffer size");

  /** Server receive buffer size */
  IntConfOption SERVER_RECEIVE_BUFFER_SIZE =
      new IntConfOption("giraph.serverReceiveBufferSize", 512 * ONE_KB,
          "Server receive buffer size");

  /** Maximum size of messages (in bytes) per peer before flush */
  IntConfOption MAX_MSG_REQUEST_SIZE =
      new IntConfOption("giraph.msgRequestSize", 512 * ONE_KB,
          "Maximum size of messages (in bytes) per peer before flush");

  /**
   * How much bigger than the average per partition size to make initial per
   * partition buffers.
   * If this value is A, message request size is M,
   * and a worker has P partitions, than its initial partition buffer size
   * will be (M / P) * (1 + A).
   */
  FloatConfOption ADDITIONAL_MSG_REQUEST_SIZE =
      new FloatConfOption("giraph.additionalMsgRequestSize", 0.2f,
          "How much bigger than the average per partition size to make " +
          "initial per partition buffers. If this value is A, message " +
          "request size is M, and a worker has P partitions, than its " +
          "initial partition buffer size will be (M / P) * (1 + A).");


  /** Warn if msg request size exceeds default size by this factor */
  FloatConfOption REQUEST_SIZE_WARNING_THRESHOLD = new FloatConfOption(
      "giraph.msgRequestWarningThreshold", 2.0f,
      "If request sizes are bigger than the buffer size by this factor " +
      "warnings are printed to the log and to the command line");

  /** Maximum size of vertices (in bytes) per peer before flush */
  IntConfOption MAX_VERTEX_REQUEST_SIZE =
      new IntConfOption("giraph.vertexRequestSize", 512 * ONE_KB,
          "Maximum size of vertices (in bytes) per peer before flush");

  /**
   * Additional size (expressed as a ratio) of each per-partition buffer on
   * top of the average size for vertices.
   */
  FloatConfOption ADDITIONAL_VERTEX_REQUEST_SIZE =
      new FloatConfOption("giraph.additionalVertexRequestSize", 0.2f,
          "Additional size (expressed as a ratio) of each per-partition " +
              "buffer on top of the average size.");

  /** Maximum size of edges (in bytes) per peer before flush */
  IntConfOption MAX_EDGE_REQUEST_SIZE =
      new IntConfOption("giraph.edgeRequestSize", 512 * ONE_KB,
          "Maximum size of edges (in bytes) per peer before flush");

  /**
   * Additional size (expressed as a ratio) of each per-partition buffer on
   * top of the average size for edges.
   */
  FloatConfOption ADDITIONAL_EDGE_REQUEST_SIZE =
      new FloatConfOption("giraph.additionalEdgeRequestSize", 0.2f,
          "Additional size (expressed as a ratio) of each per-partition " +
          "buffer on top of the average size.");

  /** Maximum number of mutations per partition before flush */
  IntConfOption MAX_MUTATIONS_PER_REQUEST =
      new IntConfOption("giraph.maxMutationsPerRequest", 100,
          "Maximum number of mutations per partition before flush");

  /**
   * Use message size encoding (typically better for complex objects,
   * not meant for primitive wrapped messages)
   */
  BooleanConfOption USE_MESSAGE_SIZE_ENCODING =
      new BooleanConfOption("giraph.useMessageSizeEncoding", false,
          "Use message size encoding (typically better for complex objects, " +
          "not meant for primitive wrapped messages)");

  /** Number of channels used per server */
  IntConfOption CHANNELS_PER_SERVER =
      new IntConfOption("giraph.channelsPerServer", 1,
          "Number of channels used per server");

  /** Number of flush threads per peer */
  String MSG_NUM_FLUSH_THREADS = "giraph.msgNumFlushThreads";

  /** Number of threads for vertex computation */
  IntConfOption NUM_COMPUTE_THREADS =
      new IntConfOption("giraph.numComputeThreads", 1,
          "Number of threads for vertex computation");

  /** Number of threads for input split loading */
  IntConfOption NUM_INPUT_THREADS =
      new IntConfOption("giraph.numInputThreads", 1,
          "Number of threads for input split loading");

  /** Minimum stragglers of the superstep before printing them out */
  IntConfOption PARTITION_LONG_TAIL_MIN_PRINT =
      new IntConfOption("giraph.partitionLongTailMinPrint", 1,
          "Minimum stragglers of the superstep before printing them out");

  /** Use superstep counters? (boolean) */
  BooleanConfOption USE_SUPERSTEP_COUNTERS =
      new BooleanConfOption("giraph.useSuperstepCounters", true,
          "Use superstep counters? (boolean)");

  /**
   * Input split sample percent - Used only for sampling and testing, rather
   * than an actual job.  The idea is that to test, you might only want a
   * fraction of the actual input splits from your VertexInputFormat to
   * load (values should be [0, 100]).
   */
  FloatConfOption INPUT_SPLIT_SAMPLE_PERCENT =
      new FloatConfOption("giraph.inputSplitSamplePercent", 100f,
          "Input split sample percent - Used only for sampling and testing, " +
          "rather than an actual job.  The idea is that to test, you might " +
          "only want a fraction of the actual input splits from your " +
          "VertexInputFormat to load (values should be [0, 100]).");

  /**
   * To limit outlier vertex input splits from producing too many vertices or
   * to help with testing, the number of vertices loaded from an input split
   * can be limited.  By default, everything is loaded.
   */
  LongConfOption INPUT_SPLIT_MAX_VERTICES =
      new LongConfOption("giraph.InputSplitMaxVertices", -1,
          "To limit outlier vertex input splits from producing too many " +
              "vertices or to help with testing, the number of vertices " +
              "loaded from an input split can be limited. By default, " +
              "everything is loaded.");

  /**
   * To limit outlier vertex input splits from producing too many vertices or
   * to help with testing, the number of edges loaded from an input split
   * can be limited.  By default, everything is loaded.
   */
  LongConfOption INPUT_SPLIT_MAX_EDGES =
      new LongConfOption("giraph.InputSplitMaxEdges", -1,
          "To limit outlier vertex input splits from producing too many " +
              "vertices or to help with testing, the number of edges loaded " +
              "from an input split can be limited. By default, everything is " +
              "loaded.");

  /**
   * To minimize network usage when reading input splits,
   * each worker can prioritize splits that reside on its host.
   * This, however, comes at the cost of increased load on ZooKeeper.
   * Hence, users with a lot of splits and input threads (or with
   * configurations that can't exploit locality) may want to disable it.
   */
  BooleanConfOption USE_INPUT_SPLIT_LOCALITY =
      new BooleanConfOption("giraph.useInputSplitLocality", true,
          "To minimize network usage when reading input splits, each worker " +
          "can prioritize splits that reside on its host. " +
          "This, however, comes at the cost of increased load on ZooKeeper. " +
          "Hence, users with a lot of splits and input threads (or with " +
          "configurations that can't exploit locality) may want to disable " +
          "it.");

  /** Multiplier for the current workers squared */
  FloatConfOption PARTITION_COUNT_MULTIPLIER =
      new FloatConfOption("giraph.masterPartitionCountMultiplier", 1.0f,
          "Multiplier for the current workers squared");

  /** Minimum number of partitions to have per compute thread */
  IntConfOption MIN_PARTITIONS_PER_COMPUTE_THREAD =
      new IntConfOption("giraph.minPartitionsPerComputeThread", 1,
          "Minimum number of partitions to have per compute thread");

  /** Overrides default partition count calculation if not -1 */
  IntConfOption USER_PARTITION_COUNT =
      new IntConfOption("giraph.userPartitionCount", -1,
          "Overrides default partition count calculation if not -1");

  /** Vertex key space size for
   * {@link org.apache.giraph.partition.WorkerGraphPartitionerImpl}
   */
  String PARTITION_VERTEX_KEY_SPACE_SIZE = "giraph.vertexKeySpaceSize";

  /**
   *  How often to checkpoint (i.e. 0, means no checkpoint,
   *  1 means every superstep, 2 is every two supersteps, etc.).
   */
  IntConfOption CHECKPOINT_FREQUENCY =
      new IntConfOption("giraph.checkpointFrequency", 0,
          "How often to checkpoint (i.e. 0, means no checkpoint, 1 means " +
          "every superstep, 2 is every two supersteps, etc.).");

  /**
   * Delete checkpoints after a successful job run?
   */
  BooleanConfOption CLEANUP_CHECKPOINTS_AFTER_SUCCESS =
      new BooleanConfOption("giraph.cleanupCheckpointsAfterSuccess", true,
          "Delete checkpoints after a successful job run?");

  /**
   * An application can be restarted manually by selecting a superstep.  The
   * corresponding checkpoint must exist for this to work.  The user should
   * set a long value.  Default is start from scratch.
   */
  String RESTART_SUPERSTEP = "giraph.restartSuperstep";

  /**
   * If application is restarted manually we need to specify job ID
   * to restart from.
   */
  StrConfOption RESTART_JOB_ID = new StrConfOption("giraph.restart.jobId",
      null, "Which job ID should I try to restart?");

  /**
   * Base ZNode for Giraph's state in the ZooKeeper cluster.  Must be a root
   * znode on the cluster beginning with "/"
   */
  String BASE_ZNODE_KEY = "giraph.zkBaseZNode";

  /**
   * If ZOOKEEPER_LIST is not set, then use this directory to manage
   * ZooKeeper
   */
  StrConfOption ZOOKEEPER_MANAGER_DIRECTORY =
      new StrConfOption("giraph.zkManagerDirectory",
          "_bsp/_defaultZkManagerDir",
          "If ZOOKEEPER_LIST is not set, then use this directory to manage " +
          "ZooKeeper");

  /** Number of ZooKeeper client connection attempts before giving up. */
  IntConfOption ZOOKEEPER_CONNECTION_ATTEMPTS =
      new IntConfOption("giraph.zkConnectionAttempts", 10,
          "Number of ZooKeeper client connection attempts before giving up.");

  /** This directory has/stores the available checkpoint files in HDFS. */
  StrConfOption CHECKPOINT_DIRECTORY =
      new StrConfOption("giraph.checkpointDirectory", "_bsp/_checkpoints/",
          "This directory has/stores the available checkpoint files in HDFS.");

  /**
   * Comma-separated list of directories in the local filesystem for
   * out-of-core partitions.
   */
  StrConfOption PARTITIONS_DIRECTORY =
      new StrConfOption("giraph.partitionsDirectory", "_bsp/_partitions",
          "Comma-separated list of directories in the local filesystem for " +
          "out-of-core partitions.");

  /**
   * Number of IO threads used in out-of-core mechanism. If local disk is used
   * for spilling data to and reading data from, this number should be equal to
   * the number of available disks on each machine. In such case, one should
   * use giraph.partitionsDirectory to specify directories mounted on different
   * disks.
   */
  IntConfOption NUM_OUT_OF_CORE_THREADS =
      new IntConfOption("giraph.numOutOfCoreThreads", 1, "Number of IO " +
          "threads used in out-of-core mechanism. If using local disk to " +
          "spill data, this should be equal to the number of available " +
          "disks. In such case, use giraph.partitionsDirectory to specify " +
          "mount points on different disks.");

  /** Enable out-of-core graph. */
  BooleanConfOption USE_OUT_OF_CORE_GRAPH =
      new BooleanConfOption("giraph.useOutOfCoreGraph", false,
          "Enable out-of-core graph.");

  /** Data accessor resource/object */
  ClassConfOption<OutOfCoreDataAccessor> OUT_OF_CORE_DATA_ACCESSOR =
      ClassConfOption.create("giraph.outOfCoreDataAccessor",
          LocalDiskDataAccessor.class, OutOfCoreDataAccessor.class,
          "Data accessor used in out-of-core computation (local-disk, " +
              "in-memory, HDFS, etc.)");

  /**
   * Out-of-core oracle that is to be used for adaptive out-of-core engine. If
   * the `MAX_PARTITIONS_IN_MEMORY` is already set, this will be over-written
   * to be `FixedPartitionsOracle`.
   */
  ClassConfOption<OutOfCoreOracle> OUT_OF_CORE_ORACLE =
      ClassConfOption.create("giraph.outOfCoreOracle",
          ThresholdBasedOracle.class, OutOfCoreOracle.class,
          "Out-of-core oracle that is to be used for adaptive out-of-core " +
              "engine");

  /** Maximum number of partitions to hold in memory for each worker. */
  IntConfOption MAX_PARTITIONS_IN_MEMORY =
      new IntConfOption("giraph.maxPartitionsInMemory", 0,
          "Maximum number of partitions to hold in memory for each worker. By" +
              " default it is set to 0 (for adaptive out-of-core mechanism");

  /** Directory to write YourKit snapshots to */
  String YOURKIT_OUTPUT_DIR = "giraph.yourkit.outputDir";
  /** Default directory to write YourKit snapshots to */
  String YOURKIT_OUTPUT_DIR_DEFAULT = "/tmp/giraph/%JOB_ID%/%TASK_ID%";

  /** Keep the zookeeper output for debugging? Default is to remove it. */
  BooleanConfOption KEEP_ZOOKEEPER_DATA =
      new BooleanConfOption("giraph.keepZooKeeperData", false,
          "Keep the zookeeper output for debugging? Default is to remove it.");
  /** Default ZooKeeper snap count. */
  int DEFAULT_ZOOKEEPER_SNAP_COUNT = 50000;
  /** Default ZooKeeper tick time. */
  int DEFAULT_ZOOKEEPER_TICK_TIME = 6000;
  /** Default ZooKeeper maximum client connections. */
  int DEFAULT_ZOOKEEPER_MAX_CLIENT_CNXNS = 10000;
  /** Number of snapshots to be retained after purge */
  int ZOOKEEPER_SNAP_RETAIN_COUNT = 3;
  /** Zookeeper purge interval in hours */
  int ZOOKEEPER_PURGE_INTERVAL = 1;
  /** ZooKeeper minimum session timeout */
  IntConfOption ZOOKEEPER_MIN_SESSION_TIMEOUT =
      new IntConfOption("giraph.zKMinSessionTimeout", MINUTES.toMillis(10),
          "ZooKeeper minimum session timeout");
  /** ZooKeeper maximum session timeout */
  IntConfOption ZOOKEEPER_MAX_SESSION_TIMEOUT =
      new IntConfOption("giraph.zkMaxSessionTimeout", MINUTES.toMillis(15),
          "ZooKeeper maximum session timeout");

  /** ZooKeeper force sync */
  BooleanConfOption ZOOKEEPER_FORCE_SYNC =
      new BooleanConfOption("giraph.zKForceSync", false,
          "ZooKeeper force sync");

  /** ZooKeeper skip ACLs */
  BooleanConfOption ZOOKEEPER_SKIP_ACL =
      new BooleanConfOption("giraph.ZkSkipAcl", true, "ZooKeeper skip ACLs");

  /**
   * Whether to use SASL with DIGEST and Hadoop Job Tokens to authenticate
   * and authorize Netty BSP Clients to Servers.
   */
  BooleanConfOption AUTHENTICATE =
      new BooleanConfOption("giraph.authenticate", false,
          "Whether to use SASL with DIGEST and Hadoop Job Tokens to " +
          "authenticate and authorize Netty BSP Clients to Servers.");

  /** Use unsafe serialization? */
  BooleanConfOption USE_UNSAFE_SERIALIZATION =
      new BooleanConfOption("giraph.useUnsafeSerialization", true,
          "Use unsafe serialization?");

  /**
   * Use BigDataIO for messages? If there are super-vertices in the
   * graph which receive a lot of messages (total serialized size of messages
   * goes beyond the maximum size of a byte array), setting this option to true
   * will remove that limit. The maximum memory available for a single vertex
   * will be limited to the maximum heap size available.
   */
  BooleanConfOption USE_BIG_DATA_IO_FOR_MESSAGES =
      new BooleanConfOption("giraph.useBigDataIOForMessages", false,
          "Use BigDataIO for messages?");

  /**
   * Maximum number of attempts a master/worker will retry before killing
   * the job.  This directly maps to the number of map task attempts in
   * Hadoop.
   */
  IntConfOption MAX_TASK_ATTEMPTS =
      new IntConfOption("mapred.map.max.attempts", -1,
          "Maximum number of attempts a master/worker will retry before " +
          "killing the job.  This directly maps to the number of map task " +
          "attempts in Hadoop.");

  /** Interface to use for hostname resolution */
  StrConfOption DNS_INTERFACE =
      new StrConfOption("giraph.dns.interface", "default",
          "Interface to use for hostname resolution");
  /** Server for hostname resolution */
  StrConfOption DNS_NAMESERVER =
      new StrConfOption("giraph.dns.nameserver", "default",
          "Server for hostname resolution");

  /**
   * The application will halt after this many supersteps is completed.  For
   * instance, if it is set to 3, the application will run at most 0, 1,
   * and 2 supersteps and then go into the shutdown superstep.
   */
  IntConfOption MAX_NUMBER_OF_SUPERSTEPS =
      new IntConfOption("giraph.maxNumberOfSupersteps", 1,
          "The application will halt after this many supersteps is " +
          "completed. For instance, if it is set to 3, the application will " +
          "run at most 0, 1, and 2 supersteps and then go into the shutdown " +
          "superstep.");

  /**
   * The application will not mutate the graph topology (the edges). It is used
   * to optimise out-of-core graph, by not writing back edges every time.
   */
  BooleanConfOption STATIC_GRAPH =
      new BooleanConfOption("giraph.isStaticGraph", false,
          "The application will not mutate the graph topology (the edges). " +
          "It is used to optimise out-of-core graph, by not writing back " +
          "edges every time.");

  /**
   * This option will tell which message encode & store enum to use when
   * combining is not enabled
   */
  EnumConfOption<MessageEncodeAndStoreType> MESSAGE_ENCODE_AND_STORE_TYPE =
      EnumConfOption.create("giraph.messageEncodeAndStoreType",
          MessageEncodeAndStoreType.class,
          MessageEncodeAndStoreType.BYTEARRAY_PER_PARTITION,
          "Select the message_encode_and_store_type to use");

  /**
   * This option can be used to specify if a source vertex present in edge
   * input but not in vertex input can be created
   */
  BooleanConfOption CREATE_EDGE_SOURCE_VERTICES =
      new BooleanConfOption("giraph.createEdgeSourceVertices", true,
          "Create a source vertex if present in edge input but not " +
          "necessarily in vertex input");

  /**
   * This counter group will contain one counter whose name is the ZooKeeper
   * server:port which this job is using
   */
  String ZOOKEEPER_SERVER_PORT_COUNTER_GROUP = "Zookeeper server:port";

  /**
   * This counter group will contain one counter whose name is the ZooKeeper
   * node path which should be created to trigger computation halt
   */
  String ZOOKEEPER_HALT_NODE_COUNTER_GROUP = "Zookeeper halt node";

  /**
   * This counter group will contain one counter whose name is the ZooKeeper
   * node path which contains all data about this job
   */
  String ZOOKEEPER_BASE_PATH_COUNTER_GROUP = "Zookeeper base path";

  /**
   * Which class to use to write instructions on how to halt the application
   */
  ClassConfOption<HaltApplicationUtils.HaltInstructionsWriter>
  HALT_INSTRUCTIONS_WRITER_CLASS = ClassConfOption.create(
      "giraph.haltInstructionsWriter",
      HaltApplicationUtils.DefaultHaltInstructionsWriter.class,
      HaltApplicationUtils.HaltInstructionsWriter.class,
      "Class used to write instructions on how to halt the application");

  /**
   * Maximum timeout (in milliseconds) for waiting for all tasks
   * to complete after the job is done.  Defaults to 15 minutes.
   */
  IntConfOption WAIT_TASK_DONE_TIMEOUT_MS =
      new IntConfOption("giraph.waitTaskDoneTimeoutMs", MINUTES.toMillis(15),
          "Maximum timeout (in ms) for waiting for all all tasks to " +
              "complete");

  /** Whether to track job progress on client or not */
  BooleanConfOption TRACK_JOB_PROGRESS_ON_CLIENT =
      new BooleanConfOption("giraph.trackJobProgressOnClient", false,
          "Whether to track job progress on client or not");

  /** Class to use to track job progress on client */
  ClassConfOption<JobProgressTrackerService> JOB_PROGRESS_TRACKER_CLASS =
      ClassConfOption.create("giraph.jobProgressTrackerClass",
          DefaultJobProgressTrackerService.class,
          JobProgressTrackerService.class,
          "Class to use to track job progress on client");

  /** Number of retries for creating the HDFS files */
  IntConfOption HDFS_FILE_CREATION_RETRIES =
      new IntConfOption("giraph.hdfs.file.creation.retries", 10,
          "Retries to create an HDFS file before failing");

  /** Number of milliseconds to wait before retrying HDFS file creation */
  IntConfOption HDFS_FILE_CREATION_RETRY_WAIT_MS =
      new IntConfOption("giraph.hdfs.file.creation.retry.wait.ms", 30_000,
          "Milliseconds to wait prior to retrying creation of an HDFS file");

  /** Number of threads for writing and reading checkpoints */
  IntConfOption NUM_CHECKPOINT_IO_THREADS =
      new IntConfOption("giraph.checkpoint.io.threads", 8,
          "Number of threads for writing and reading checkpoints");

  /**
   * Compression algorithm to be used for checkpointing.
   * Defined by extension for hadoop compatibility reasons.
   */
  StrConfOption CHECKPOINT_COMPRESSION_CODEC =
      new StrConfOption("giraph.checkpoint.compression.codec",
          ".deflate",
          "Defines compression algorithm we will be using for " +
              "storing checkpoint. Available options include but " +
              "not restricted to: .deflate, .gz, .bz2, .lzo");

  /**
   * Defines if and when checkpointing is supported by this job.
   * By default checkpointing is always supported unless output during the
   * computation is enabled.
   */
  ClassConfOption<CheckpointSupportedChecker> CHECKPOINT_SUPPORTED_CHECKER =
      ClassConfOption.create("giraph.checkpoint.supported.checker",
          DefaultCheckpointSupportedChecker.class,
          CheckpointSupportedChecker.class,
          "This is the way to specify if checkpointing is " +
              "supported by the job");


  /** Number of threads to use in async message store, 0 means
   * we should not use async message processing */
  IntConfOption ASYNC_MESSAGE_STORE_THREADS_COUNT =
      new IntConfOption("giraph.async.message.store.threads", 0,
          "Number of threads to be used in async message store.");

  /** Output format class for hadoop to use (for committing) */
  ClassConfOption<OutputFormat> HADOOP_OUTPUT_FORMAT_CLASS =
      ClassConfOption.create("giraph.hadoopOutputFormatClass",
          BspOutputFormat.class, OutputFormat.class,
          "Output format class for hadoop to use (for committing)");

  /**
   * For worker to worker communication we can use IPs or host names, by
   * default prefer IPs.
   */
  BooleanConfOption PREFER_IP_ADDRESSES =
      new BooleanConfOption("giraph.preferIP", false,
      "Prefer IP addresses instead of host names");
}
// CHECKSTYLE: resume InterfaceIsTypeCheck