Package org.apache.druid.server

Class QueryResultPusher

java.lang.Object

org.apache.druid.server.QueryResultPusher

public abstract class QueryResultPusher
extends Object

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	QueryResultPusher.ResultsWriter
class	QueryResultPusher.StreamingHttpResponseAccumulator
static interface	QueryResultPusher.Writer

Constructor Summary

Constructors

Constructor	Description
QueryResultPusher(javax.servlet.http.HttpServletRequest request, com.fasterxml.jackson.databind.ObjectMapper jsonMapper, ResponseContextConfig responseContextConfig, DruidNode selfNode, QueryResource.QueryMetricCounter counter, String queryId, javax.ws.rs.core.MediaType contentType, Map<String,String> extraHeaders)

Method Summary

Modifier and Type	Method	Description
javax.ws.rs.core.Response	push()	Pushes results out.
abstract QueryResultPusher.ResultsWriter	start()	Builds a ResultsWriter to start the lifecycle of the QueryResultPusher.
abstract void	writeException(Exception e, OutputStream out)

Methods inherited from class java.lang.Object

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

Constructor Detail

QueryResultPusher

public QueryResultPusher(javax.servlet.http.HttpServletRequest request,
                         com.fasterxml.jackson.databind.ObjectMapper jsonMapper,
                         ResponseContextConfig responseContextConfig,
                         DruidNode selfNode,
                         QueryResource.QueryMetricCounter counter,
                         String queryId,
                         javax.ws.rs.core.MediaType contentType,
                         Map<String,String> extraHeaders)

Method Detail

start

public abstract QueryResultPusher.ResultsWriter start()

Builds a ResultsWriter to start the lifecycle of the QueryResultPusher. The ResultsWriter encapsulates the logic to run the query, serialize it and also report success/failure.

This response must not be null. The job of this ResultsWriter is largely to provide lifecycle management to the query running and reporting, so this object must never be null.

This start() method should do as little work as possible, it should really just make the ResultsWriter and return.

Returns:

a new ResultsWriter

writeException

public abstract void writeException(Exception e,
                                    OutputStream out)
                             throws IOException

Throws:

IOException

push

@Nullable
public javax.ws.rs.core.Response push()

Pushes results out. Can sometimes return a JAXRS Response object instead of actually pushing to the output stream, primarily for error handling that occurs before switching the servlet to asynchronous mode.

Returns:

null if the response has already been handled and pushed out, or a non-null Response object if it expects the container to put the bytes on the wire.