com.yahoo.bard.webservice.web.handlers

Class EtagCacheRequestHandler

java.lang.Object

com.yahoo.bard.webservice.web.handlers.BaseDataRequestHandler

com.yahoo.bard.webservice.web.handlers.EtagCacheRequestHandler

All Implemented Interfaces:

DataRequestHandler

public class EtagCacheRequestHandler
extends BaseDataRequestHandler

Request handler to check the cache for a matching eTag.

If a query is cached, the etag of the query is retrieved from the cache and is injected into query request header

Etag-based cache mechanism relies entirely on Druid's etags to determine a cache hit or miss.

Field Summary

Fields

Modifier and Type	Field and Description
protected TupleDataCache<String,String,String>	dataCache
protected DataRequestHandler	next

Fields inherited from class com.yahoo.bard.webservice.web.handlers.BaseDataRequestHandler

mapper, writer

Constructor Summary

Constructors

Constructor and Description
EtagCacheRequestHandler(DataRequestHandler next, TupleDataCache<String,String,String> dataCache, com.fasterxml.jackson.databind.ObjectMapper mapper) Build a Cache request handler.

Method Summary

Modifier and Type	Method and Description
boolean	handleRequest(RequestContext context, DataApiRequest request, DruidAggregationQuery<?> druidQuery, ResponseProcessor response) Handle the response, passing the request down the chain as necessary.

Methods inherited from class java.lang.Object

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

Field Detail

next

protected final DataRequestHandler next

dataCache

protected final TupleDataCache<String,String,String> dataCache

Constructor Detail

EtagCacheRequestHandler

public EtagCacheRequestHandler(@NotNull
                               DataRequestHandler next,
                               @NotNull
                               TupleDataCache<String,String,String> dataCache,
                               @NotNull
                               com.fasterxml.jackson.databind.ObjectMapper mapper)

Build a Cache request handler.

Parameters:

next - The next handler in the chain

dataCache - The cache instance

mapper - The mapper for all JSON processing

Method Detail

handleRequest

public boolean handleRequest(RequestContext context,
                             DataApiRequest request,
                             DruidAggregationQuery<?> druidQuery,
                             ResponseProcessor response)

Description copied from interface: DataRequestHandler

Handle the response, passing the request down the chain as necessary.

Parameters:

context - The context for the Request

request - The Api Request Object

druidQuery - The druid query

response - The Async response

Returns:

True if the async response has been processed or passed to a future for processing