org.apache.druid.query.context

Class ResponseContext

java.lang.Object

org.apache.druid.query.context.ResponseContext

Direct Known Subclasses:

ConcurrentResponseContext, DefaultResponseContext

public abstract class ResponseContext
extends Object

The context for storing and passing data between chains of QueryRunners. The context is also transferred between Druid nodes with all the data it contains.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	ResponseContext.BaseKey The base interface of a response context key.
static class	ResponseContext.Key Keys associated with objects in the context.
static class	ResponseContext.SerializationResult Serialization result of ResponseContext.

Constructor Summary

Constructors

Constructor and Description
ResponseContext()

Method Summary

Modifier and Type	Method and Description
Object	add(ResponseContext.BaseKey key, Object value) Adds (merges) a new value associated with a key to an old value.
static ResponseContext	createEmpty() Create an empty DefaultResponseContext instance
static ResponseContext	deserialize(String responseContext, com.fasterxml.jackson.databind.ObjectMapper objectMapper) Deserializes a string into ResponseContext using given ObjectMapper.
Object	get(ResponseContext.BaseKey key)
protected abstract Map<ResponseContext.BaseKey,Object>	getDelegate()
void	merge(ResponseContext responseContext) Merges a response context into the current.
Object	put(ResponseContext.BaseKey key, Object value) Associates the specified object with the specified key.
Object	remove(ResponseContext.BaseKey key)
ResponseContext.SerializationResult	serializeWith(com.fasterxml.jackson.databind.ObjectMapper objectMapper, int maxCharsNumber) Serializes the context given that the resulting string length is less than the provided limit.

Methods inherited from class java.lang.Object

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

Constructor Detail

ResponseContext

public ResponseContext()

Method Detail

getDelegate

protected abstract Map<ResponseContext.BaseKey,Object> getDelegate()

createEmpty

public static ResponseContext createEmpty()

Create an empty DefaultResponseContext instance

Returns:

empty DefaultResponseContext instance

deserialize

public static ResponseContext deserialize(String responseContext,
                                          com.fasterxml.jackson.databind.ObjectMapper objectMapper)
                                   throws IOException

Deserializes a string into ResponseContext using given ObjectMapper.

Throws:

IllegalStateException - if one of the deserialized map keys has not been registered.

IOException

put

public Object put(ResponseContext.BaseKey key,
                  Object value)

Associates the specified object with the specified key.

Throws:

IllegalStateException - if the key has not been registered.

get

public Object get(ResponseContext.BaseKey key)

remove

public Object remove(ResponseContext.BaseKey key)

add

public Object add(ResponseContext.BaseKey key,
                  Object value)

Adds (merges) a new value associated with a key to an old value. See merge function of a context key for a specific implementation.

Throws:

IllegalStateException - if the key has not been registered.

merge

public void merge(ResponseContext responseContext)

Merges a response context into the current.

Throws:

IllegalStateException - If a key of the responseContext has not been registered.

serializeWith

public ResponseContext.SerializationResult serializeWith(com.fasterxml.jackson.databind.ObjectMapper objectMapper,
                                                         int maxCharsNumber)
                                                  throws com.fasterxml.jackson.core.JsonProcessingException

Serializes the context given that the resulting string length is less than the provided limit. This method removes some elements from context collections if it's needed to satisfy the limit. There is no explicit priorities of keys which values are being truncated because for now there are only two potential limit breaking keys (ResponseContext.Key.UNCOVERED_INTERVALS and ResponseContext.Key.MISSING_SEGMENTS) and their values are arrays. Thus current implementation considers these arrays as equal prioritized and starts removing elements from the array which serialized value length is the biggest. The resulting string might be correctly deserialized to ResponseContext.

Throws:

com.fasterxml.jackson.core.JsonProcessingException