Package org.apache.druid.segment.column

Class TypeStrategies.FloatTypeStrategy

java.lang.Object

org.apache.druid.segment.column.TypeStrategies.FloatTypeStrategy

All Implemented Interfaces:

Comparator<Object>, TypeStrategy<Float>

Enclosing class:

TypeStrategies

public static final class TypeStrategies.FloatTypeStrategy
extends Object
implements TypeStrategy<Float>

Read and write non-null FLOAT values. If reading non-null values, consider just using ByteBuffer.getFloat() directly, or if reading values written with NullableTypeStrategy, using TypeStrategies.isNullableNull(java.nio.ByteBuffer, int) and TypeStrategies.readNotNullNullableFloat(java.nio.ByteBuffer, int), both of which allow dealing in primitive float values instead of objects.

Constructor Summary

Constructors

Constructor	Description
FloatTypeStrategy()

Method Summary

Modifier and Type	Method	Description
int	compare(Object o1, Object o2)
int	estimateSizeBytes(Float value)	Estimate the size in bytes that writing this value to memory would require.
Float	read(ByteBuffer buffer)	Read a non-null value from the ByteBuffer at the current Buffer.position().
Float	read(ByteBuffer buffer, int offset)	Read a non-null value from the ByteBuffer at the requested position.
boolean	readRetainsBufferReference()	Whether the TypeStrategy.read(java.nio.ByteBuffer) methods return an object that may retain a reference to the provided ByteBuffer.
int	write(ByteBuffer buffer, Float value, int maxSizeBytes)	Write a non-null value to the ByteBuffer at position Buffer.position().

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Comparator

equals, reversed, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong

Methods inherited from interface org.apache.druid.segment.column.TypeStrategy

fromBytes, write

Constructor Detail

FloatTypeStrategy

public FloatTypeStrategy()

Method Detail

estimateSizeBytes

public int estimateSizeBytes(Float value)

Description copied from interface: TypeStrategy

Estimate the size in bytes that writing this value to memory would require. This method is not required to be exactly correct, but many implementations might be. Implementations should err on the side of over-estimating if exact sizing is not efficient. Example usage of this method is estimating heap memory usage for an aggregator or the amount of buffer which might need allocated to then TypeStrategy.write(java.nio.ByteBuffer, T, int) a value

Specified by:

estimateSizeBytes in interface TypeStrategy<Float>

read

public Float read(ByteBuffer buffer)

Description copied from interface: TypeStrategy

Read a non-null value from the ByteBuffer at the current Buffer.position(). This will move the underlying position by the size of the value read. The value returned from this method may retain a reference to the provided ByteBuffer. If it does, then TypeStrategy.readRetainsBufferReference() returns true.

Specified by:

read in interface TypeStrategy<Float>

read

public Float read(ByteBuffer buffer,
                  int offset)

Description copied from interface: TypeStrategy

Read a non-null value from the ByteBuffer at the requested position. This will not permanently move the underlying Buffer.position(), but may temporarily modify the buffer position during reading so cannot be considered thread safe usage of the buffer. The contract of this method is that any value returned from this method MUST be completely detached from the underlying ByteBuffer, since it might outlive the memory location being allocated to hold the object. In other words, if an object is memory mapped, it must be copied on heap, or relocated to another memory location that is owned by the caller with TypeStrategy.write(java.nio.ByteBuffer, T, int).

Specified by:

read in interface TypeStrategy<Float>

readRetainsBufferReference

public boolean readRetainsBufferReference()

Description copied from interface: TypeStrategy

Whether the TypeStrategy.read(java.nio.ByteBuffer) methods return an object that may retain a reference to the provided ByteBuffer. If a reference is sometimes retained, this method returns true. It returns false if, and only if, a reference is *never* retained.

Specified by:

readRetainsBufferReference in interface TypeStrategy<Float>

write

public int write(ByteBuffer buffer,
                 Float value,
                 int maxSizeBytes)

Description copied from interface: TypeStrategy

Write a non-null value to the ByteBuffer at position Buffer.position(). This will move the underlying position by the size of the value written. This method returns the number of bytes written. If writing the value would take more than 'maxSizeBytes', this method will return a negative value indicating the number of additional bytes that would be required to fully write the value. Partial results may be written to the buffer when in this state, and the position may be left at whatever point the implementation ran out of space while writing the value. Callers should save the starting position if it is necessary to 'rewind' after a partial write. Callers MUST check that the return value is positive which indicates a successful write, while a negative response a partial write.

Specified by:

write in interface TypeStrategy<Float>

Returns:

number of bytes written

compare

public int compare(Object o1,
                   Object o2)

Specified by:

compare in interface Comparator<Object>