com.espertech.esper.client.util

Interface CountMinSketchAgent

All Known Implementing Classes:

CountMinSketchAgentStringUTF16

public interface CountMinSketchAgent

For use with Count-min sketch aggregation functions: The agent implementation encapsulates transformation of value objects to byte-array and back (when needed), and may override or provide custom behavior.

Method Summary

Modifier and Type	Method and Description
void	add(CountMinSketchAgentContextAdd ctx) Add a value to the Count-min sketch.
Long	estimate(CountMinSketchAgentContextEstimate ctx) Return the estimated count for a given value.
Object	fromBytes(CountMinSketchAgentContextFromBytes ctx) Return the value object for a given byte-array, for use with top-K.
Class[]	getAcceptableValueTypes() Returns an array of types that the agent can handle, for validation purposes.

Method Detail

getAcceptableValueTypes

Class[] getAcceptableValueTypes()

Returns an array of types that the agent can handle, for validation purposes. For example, an agent that accepts byte-array type values should return "new Class[] {String.class}". Interfaces and supertype classes can also be part of the class array.

Returns:

class array of acceptable type

add

void add(CountMinSketchAgentContextAdd ctx)

Add a value to the Count-min sketch. Implementations typically check for null value, convert the value object to a byte-array and invoke a method on the state object to add the byte-array value.

Parameters:

ctx - contains value to add as well as the state

estimate

Long estimate(CountMinSketchAgentContextEstimate ctx)

Return the estimated count for a given value. Implementations typically check for null value, convert the value object to a byte-array and invoke a method on the state object to retrieve a count.

Parameters:

ctx - contains value to query as well as the state

Returns:

estimated count

fromBytes

Object fromBytes(CountMinSketchAgentContextFromBytes ctx)

Return the value object for a given byte-array, for use with top-K. Implementations typically simply convert a byte-array into a value object.

Parameters:

ctx - value object and state

Returns:

value object