com.tangosol.coherence.dslquery

Interface ExtractorBuilder

All Known Implementing Classes:

ChainedExtractorBuilder, ReflectionExtractorBuilder

public interface ExtractorBuilder

ExtractorBuilders provide a mechanism to construct a ValueExtractor for a provided cache name, target and property chain (realize(String, int, String)).

To determine the appropriate ValueExtractor implementations may need to decipher cache type information, which should be discernible from the provided cache name and nTarget (KEY or VALUE). The property chain (sProperties) represents a chain of calls from the root type (key or value) down the type hierarchy.

Implementations may be able to optimize the ValueExtractors used by CohQL by providing a mapping of a logical property name to a ValueExtractor that can optimally (without deserializing the entire key or value) extract the relevant property. For example, an implementation able to map properties to POF indices could convert a property chain to a POF path. Assuming a Person object is the value stored in a cache the table below illustrates possible implementations:

Implementation Examples

Property Chain	Unoptimized	Optimized
value().address.homeTel.areaCode	ChainedExtractor(ReflectionExtractor(getAddress), ReflectionExtractor(getHomeTel), ReflectionExtractor(getAreaCode))	PofExtractor(PofNavigator(2, 5, 7))

Since:

Coherence 12.2.1

Author:

jk 2014.07.10

See Also:

ValueExtractor

Method Summary

Modifier and Type	Method and Description
ValueExtractor	realize(String sCacheName, int nTarget, String sProperties) Create a ValueExtractor for the given cache name, target and property chain.

Method Detail

realize

ValueExtractor realize(String sCacheName,
                       int nTarget,
                       String sProperties)

Create a ValueExtractor for the given cache name, target and property chain.

Parameters:

sCacheName - the name of the cache the ValueExtractor will be invoked against

nTarget - the target for the ValueExtractor

sProperties - the path to the property value to extract

Returns:

a ValueExtractor for the given cache name, target and properties