Package org.apache.druid.query.aggregation

Class DelegatingBufferAggregator

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void aggregate​(ByteBuffer buf, int position)
      Aggregates metric values into the given aggregate byte representation Implementations of this method must read in the aggregate value from the buffer at the given position, aggregate the next element of data and write the updated aggregate value back into the buffer.
      void close()
      Release any resources used by the aggregator
      Object get​(ByteBuffer buf, int position)
      Returns the intermediate object representation of the given aggregate.
      double getDouble​(ByteBuffer buf, int position)
      Returns the double representation of the given aggregate byte array Converts the given byte buffer representation into the intermediate aggregate value.
      float getFloat​(ByteBuffer buf, int position)
      Returns the float representation of the given aggregate byte array Converts the given byte buffer representation into the intermediate aggregate value.
      long getLong​(ByteBuffer buf, int position)
      Returns the long representation of the given aggregate byte array Converts the given byte buffer representation into the intermediate aggregate value.
      void init​(ByteBuffer buf, int position)
      Initializes the buffer location Implementations of this method must initialize the byte buffer at the given position Implementations must not change the position, limit or mark of the given buffer This method must not exceed the number of bytes returned by AggregatorFactory.getMaxIntermediateSizeWithNulls() in the corresponding AggregatorFactory
      void inspectRuntimeShape​(RuntimeShapeInspector inspector)
      Implementations of this method should call inspector.visit() with all fields of this class, which meet two conditions: 1.
      boolean isNull​(ByteBuffer buf, int position)
      returns true if aggregator's output type is primitive long/double/float and aggregated value is null, but when aggregated output type is Object, this method always returns false, and users are advised to check nullability for the object returned by BufferAggregator.get(ByteBuffer, int) method.
      void relocate​(int oldPosition, int newPosition, ByteBuffer oldBuffer, ByteBuffer newBuffer)
      Relocates any cached objects.

    • Constructor Detail

      • DelegatingBufferAggregator

        public DelegatingBufferAggregator()

    • Method Detail

      • init

        public void init​(ByteBuffer buf,
                 int position)
        Description copied from interface: BufferAggregator
        Initializes the buffer location Implementations of this method must initialize the byte buffer at the given position Implementations must not change the position, limit or mark of the given buffer This method must not exceed the number of bytes returned by AggregatorFactory.getMaxIntermediateSizeWithNulls() in the corresponding AggregatorFactory
        Specified by:
        init in interface BufferAggregator
        Parameters:
        buf - byte buffer to initialize
        position - offset within the byte buffer for initialization

      • aggregate

        public void aggregate​(ByteBuffer buf,
                      int position)
        Description copied from interface: BufferAggregator
        Aggregates metric values into the given aggregate byte representation Implementations of this method must read in the aggregate value from the buffer at the given position, aggregate the next element of data and write the updated aggregate value back into the buffer. Implementations must not change the position, limit or mark of the given buffer
        Specified by:
        aggregate in interface BufferAggregator
        Parameters:
        buf - byte buffer storing the byte array representation of the aggregate
        position - offset within the byte buffer at which the current aggregate value is stored

      • get

        @Nullable
public Object get​(ByteBuffer buf,
                  int position)
        Description copied from interface: BufferAggregator
        Returns the intermediate object representation of the given aggregate. Converts the given byte buffer representation into an intermediate aggregate Object Implementations must not change the position, limit or mark of the given buffer. The object returned must not have any references to the given buffer (i.e., make a copy), since the underlying buffer is a shared resource and may be given to another processing thread while the objects returned by this aggregator are still in use. If the corresponding AggregatorFactory.combine(Object, Object) method for this aggregator expects its inputs to be mutable, then the object returned by this method must be mutable.
        Specified by:
        get in interface BufferAggregator
        Parameters:
        buf - byte buffer storing the byte array representation of the aggregate
        position - offset within the byte buffer at which the aggregate value is stored
        Returns:
        the Object representation of the aggregate

      • getFloat

        public float getFloat​(ByteBuffer buf,
                      int position)
        Description copied from interface: BufferAggregator
        Returns the float representation of the given aggregate byte array Converts the given byte buffer representation into the intermediate aggregate value. Implementations must not change the position, limit or mark of the given buffer Implementations are only required to support this method if they are aggregations which have an AggregatorFactory.getIntermediateType() ()} of ValueType.FLOAT. If unimplemented, throwing an UnsupportedOperationException is common and recommended.
        Specified by:
        getFloat in interface BufferAggregator
        Parameters:
        buf - byte buffer storing the byte array representation of the aggregate
        position - offset within the byte buffer at which the aggregate value is stored
        Returns:
        the float representation of the aggregate

      • getLong

        public long getLong​(ByteBuffer buf,
                    int position)
        Description copied from interface: BufferAggregator
        Returns the long representation of the given aggregate byte array Converts the given byte buffer representation into the intermediate aggregate value. Implementations must not change the position, limit or mark of the given buffer Implementations are only required to support this method if they are aggregations which have an AggregatorFactory.getIntermediateType() of of ValueType.LONG. If unimplemented, throwing an UnsupportedOperationException is common and recommended.
        Specified by:
        getLong in interface BufferAggregator
        Parameters:
        buf - byte buffer storing the byte array representation of the aggregate
        position - offset within the byte buffer at which the aggregate value is stored
        Returns:
        the long representation of the aggregate

      • getDouble

        public double getDouble​(ByteBuffer buf,
                        int position)
        Description copied from interface: BufferAggregator
        Returns the double representation of the given aggregate byte array Converts the given byte buffer representation into the intermediate aggregate value. Implementations must not change the position, limit or mark of the given buffer Implementations are only required to support this method if they are aggregations which have an AggregatorFactory.getIntermediateType() of of ValueType.DOUBLE. If unimplemented, throwing an UnsupportedOperationException is common and recommended. The default implementation casts BufferAggregator.getFloat(ByteBuffer, int) to double. This default method is added to enable smooth backward compatibility, please re-implement it if your aggregators work with numeric double columns.
        Specified by:
        getDouble in interface BufferAggregator
        Parameters:
        buf - byte buffer storing the byte array representation of the aggregate
        position - offset within the byte buffer at which the aggregate value is stored
        Returns:
        the double representation of the aggregate

      • relocate

        public void relocate​(int oldPosition,
                     int newPosition,
                     ByteBuffer oldBuffer,
                     ByteBuffer newBuffer)
        Description copied from interface: BufferAggregator
        Relocates any cached objects. If underlying ByteBuffer used for aggregation buffer relocates to a new ByteBuffer, positional caches(if any) built on top of old ByteBuffer can not be used for further BufferAggregator.aggregate(ByteBuffer, int) calls. This method tells the BufferAggregator that the cached objects at a certain location has been relocated to a different location. Only used if there is any positional caches/objects in the BufferAggregator implementation. If relocate happens to be across multiple new ByteBuffers (say n ByteBuffers), this method should be called multiple times(n times) given all the new positions/old positions should exist in newBuffer/OldBuffer. Implementations must not change the position, limit or mark of the given buffer
        Specified by:
        relocate in interface BufferAggregator
        Parameters:
        oldPosition - old position of a cached object before aggregation buffer relocates to a new ByteBuffer.
        newPosition - new position of a cached object after aggregation buffer relocates to a new ByteBuffer.
        oldBuffer - old aggregation buffer.
        newBuffer - new aggregation buffer.

      • isNull

        public boolean isNull​(ByteBuffer buf,
                      int position)
        Description copied from interface: BufferAggregator
        returns true if aggregator's output type is primitive long/double/float and aggregated value is null, but when aggregated output type is Object, this method always returns false, and users are advised to check nullability for the object returned by BufferAggregator.get(ByteBuffer, int) method. The default implementation always return false to enable smooth backward compatibility, re-implement if your aggregator is nullable.
        Specified by:
        isNull in interface BufferAggregator
        Parameters:
        buf - byte buffer storing the byte array representation of the aggregate
        position - offset within the byte buffer at which the aggregate value is stored
        Returns:
        true if the aggregated value is primitive long/double/float and aggregated value is null otherwise false.