io.druid.query.aggregation.histogram

Class ApproximateHistogramBufferAggregator

java.lang.Object

io.druid.query.aggregation.histogram.ApproximateHistogramBufferAggregator

All Implemented Interfaces:

BufferAggregator

public class ApproximateHistogramBufferAggregator
extends Object
implements BufferAggregator

Constructor Summary

Constructors

Constructor and Description
ApproximateHistogramBufferAggregator(FloatColumnSelector selector, int resolution, float lowerLimit, float upperLimit)

Method Summary

Methods

Modifier and Type	Method and 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.
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.
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.getMaxIntermediateSize() in the corresponding AggregatorFactory

Methods inherited from class java.lang.Object

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

Constructor Detail

ApproximateHistogramBufferAggregator

public ApproximateHistogramBufferAggregator(FloatColumnSelector selector,
                                    int resolution,
                                    float lowerLimit,
                                    float upperLimit)

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.getMaxIntermediateSize() 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

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

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.getTypeName() of "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

close

public void close()

Description copied from interface: BufferAggregator

Release any resources used by the aggregator

Specified by:

close in interface BufferAggregator