Package org.apache.hadoop.mapreduce

Class TaskAttemptID

java.lang.Object
org.apache.hadoop.mapreduce.ID
org.apache.hadoop.mapred.ID
org.apache.hadoop.mapreduce.TaskAttemptID
All Implemented Interfaces:
Comparable<ID>, Writable, WritableComparable<ID>
Direct Known Subclasses:
TaskAttemptID
@Public @Stable public class TaskAttemptID extends ID
TaskAttemptID represents the immutable and unique identifier for a task attempt. Each task attempt is one particular instance of a Map or Reduce Task identified by its TaskID. TaskAttemptID consists of 2 parts. First part is the TaskID, that this TaskAttemptID belongs to. Second part is the task attempt number.
An example TaskAttemptID is : attempt_200707121733_0003_m_000005_0 , which represents the zeroth task attempt for the fifth map task in the third job running at the jobtracker started at 200707121733.

Applications should never construct or parse TaskAttemptID strings , but rather use appropriate constructors or forName(String) method.

See Also:

  • Field Details

  • Constructor Details

    • TaskAttemptID

      public TaskAttemptID(TaskID taskId, int id)
      Constructs a TaskAttemptID object from given TaskID.
      Parameters:
      taskId - TaskID that this task belongs to
      id - the task attempt number

    • TaskAttemptID

      public TaskAttemptID(String jtIdentifier, int jobId, TaskType type, int taskId, int id)
      Constructs a TaskId object from given parts.
      Parameters:
      jtIdentifier - jobTracker identifier
      jobId - job number
      type - the TaskType
      taskId - taskId number
      id - the task attempt number

    • TaskAttemptID

      @Deprecated public TaskAttemptID(String jtIdentifier, int jobId, boolean isMap, int taskId, int id)
      Deprecated.
      Constructs a TaskId object from given parts.
      Parameters:
      jtIdentifier - jobTracker identifier
      jobId - job number
      isMap - whether the tip is a map
      taskId - taskId number
      id - the task attempt number

    • TaskAttemptID

      public TaskAttemptID()

  • Method Details

    • getJobID

      public JobID getJobID()
      Returns the JobID object that this task attempt belongs to

    • getTaskID

      public TaskID getTaskID()
      Returns the TaskID object that this task attempt belongs to

    • isMap

      @Deprecated public boolean isMap()
      Deprecated.
      Returns whether this TaskID is a map ID

    • getTaskType

      public TaskType getTaskType()
      Returns the TaskType of the TaskAttemptID

    • equals

      public boolean equals(Object o)
      Overrides:
      equals in class ID

    • appendTo

      protected StringBuilder appendTo(StringBuilder builder)
      Add the unique string to the StringBuilder
      Parameters:
      builder - the builder to append ot
      Returns:
      the builder that was passed in.

    • readFields

      public void readFields(DataInput in) throws IOException
      Description copied from interface: Writable
      Deserialize the fields of this object from in.

      For efficiency, implementations should attempt to re-use storage in the existing object where possible.

      Specified by:
      readFields in interface Writable
      Overrides:
      readFields in class ID
      Parameters:
      in - DataInput to deseriablize this object from.
      Throws:
      IOException - any other problem for readFields.

    • write

      public void write(DataOutput out) throws IOException
      Description copied from interface: Writable
      Serialize the fields of this object to out.
      Specified by:
      write in interface Writable
      Overrides:
      write in class ID
      Parameters:
      out - DataOuput to serialize this object into.
      Throws:
      IOException - any other problem for write.

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class ID

    • compareTo

      public int compareTo(ID o)
      Compare TaskIds by first tipIds, then by task numbers.
      Specified by:
      compareTo in interface Comparable<ID>
      Overrides:
      compareTo in class ID

    • toString

      public String toString()
      Overrides:
      toString in class ID

    • forName

      public static TaskAttemptID forName(String str) throws IllegalArgumentException
      Construct a TaskAttemptID object from given string
      Returns:
      constructed TaskAttemptID object or null if the given String is null
      Throws:
      IllegalArgumentException - if the given string is malformed