ByteKeyRangeTracker (Google Cloud Dataflow SDK 1.9.1 API)

Google Cloud Dataflow SDK for Java, version 1.9.1

Warning: Dataflow SDK 1.x for Java is unsupported as of October 16, 2018. See Migrating from Dataflow SDK 1.x for Java for migration guidance.

Note: If you are using Cloud Dataflow SDK version 2.x, see the Apache Beam API reference documentation.

com.google.cloud.dataflow.sdk.io.range

Class ByteKeyRangeTracker

• java.lang.Object
• • com.google.cloud.dataflow.sdk.io.range.ByteKeyRangeTracker

• All Implemented Interfaces:

  RangeTracker<ByteKey>

  ---

  
  

  public final class ByteKeyRangeTracker
  extends Object
  implements RangeTracker<ByteKey>

  A RangeTracker for ByteKeys in ByteKeyRanges.

  See Also:

  ByteKey, ByteKeyRange

• • Method Summary

    All Methods Static Methods Instance Methods Concrete Methods 

    Modifier and Type	Method and Description
    double	getFractionConsumed() Returns the approximate fraction of positions in the source that have been consumed by successful RangeTracker.tryReturnRecordAt(boolean, PositionT) calls, or 0.0 if no such calls have happened.
    ByteKeyRange	getRange() Returns the current range.
    long	getSplitPointsConsumed()
    ByteKey	getStartPosition() Returns the starting position of the current range, inclusive.
    ByteKey	getStopPosition() Returns the ending position of the current range, exclusive.
    boolean	isDone()
    boolean	markDone() Marks this range tracker as being done.
    static ByteKeyRangeTracker	of(ByteKeyRange range) Instantiates a new ByteKeyRangeTracker with the specified range.
    String	toString()
    boolean	tryReturnRecordAt(boolean isAtSplitPoint, ByteKey recordStart) Atomically determines whether a record at the given position can be returned and updates internal state.
    boolean	trySplitAtPosition(ByteKey splitPosition) Atomically splits the current range [RangeTracker.getStartPosition(), RangeTracker.getStopPosition()) into a "primary" part [RangeTracker.getStartPosition(), splitPosition) and a "residual" part [splitPosition, RangeTracker.getStopPosition()), assuming the current last-consumed position is within [RangeTracker.getStartPosition(), splitPosition) (i.e., splitPosition has not been consumed yet).

    • Methods inherited from class java.lang.Object

      clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

• • Method Detail

    • of

      public static ByteKeyRangeTracker of(ByteKeyRange range)

      Instantiates a new ByteKeyRangeTracker with the specified range.

    • isDone

      public boolean isDone()

    • getStartPosition

      public ByteKey getStartPosition()

      Description copied from interface: RangeTracker
      Returns the starting position of the current range, inclusive.

      Specified by:

      getStartPosition in interface RangeTracker<ByteKey>

    • getStopPosition

      public ByteKey getStopPosition()

      Description copied from interface: RangeTracker
      Returns the ending position of the current range, exclusive.

      Specified by:

      getStopPosition in interface RangeTracker<ByteKey>

    • getRange

      public ByteKeyRange getRange()

      Returns the current range.

    • tryReturnRecordAt

      public boolean tryReturnRecordAt(boolean isAtSplitPoint,
                                       ByteKey recordStart)

      Description copied from interface: RangeTracker
      Atomically determines whether a record at the given position can be returned and updates internal state. In particular:

      • If isAtSplitPoint is true, and recordStart is outside the current range, returns false;
      • Otherwise, updates the last-consumed position to recordStart and returns true.

      This method MUST be called on all split point records. It may be called on every record.

      Specified by:

      tryReturnRecordAt in interface RangeTracker<ByteKey>

    • trySplitAtPosition

      public boolean trySplitAtPosition(ByteKey splitPosition)

      Description copied from interface: RangeTracker
      Atomically splits the current range [RangeTracker.getStartPosition(), RangeTracker.getStopPosition()) into a "primary" part [RangeTracker.getStartPosition(), splitPosition) and a "residual" part [splitPosition, RangeTracker.getStopPosition()), assuming the current last-consumed position is within [RangeTracker.getStartPosition(), splitPosition) (i.e., splitPosition has not been consumed yet).

      Updates the current range to be the primary and returns true. This means that all further calls on the current object will interpret their arguments relative to the primary range.

      If the split position has already been consumed, or if no RangeTracker.tryReturnRecordAt(boolean, PositionT) call was made yet, returns false. The second condition is to prevent dynamic splitting during reader start-up.

      Specified by:

      trySplitAtPosition in interface RangeTracker<ByteKey>

    • getFractionConsumed

      public double getFractionConsumed()

      Description copied from interface: RangeTracker
      Returns the approximate fraction of positions in the source that have been consumed by successful RangeTracker.tryReturnRecordAt(boolean, PositionT) calls, or 0.0 if no such calls have happened.

      Specified by:

      getFractionConsumed in interface RangeTracker<ByteKey>

    • getSplitPointsConsumed

      public long getSplitPointsConsumed()

    • markDone

      public boolean markDone()

      Marks this range tracker as being done. Specifically, this will mark the current split point, if one exists, as being finished.

      Always returns false, so that it can be used in an implementation of Source.Reader.start() or Source.Reader.advance() as follows:

       
       public boolean start() {
         return startImpl() && rangeTracker.tryReturnRecordAt(isAtSplitPoint, position)
             || rangeTracker.markDone();
       } 

    • toString

      public String toString()

      Overrides:

      toString in class Object