org.apache.calcite.avatica.remote

Class AbstractHandler<T>

java.lang.Object

org.apache.calcite.avatica.remote.AbstractHandler<T>

Type Parameters:

T - The format Requests/Responses are serialized as.

All Implemented Interfaces:

Handler<T>

Direct Known Subclasses:

JsonHandler, ProtobufHandler

public abstract class AbstractHandler<T>
extends Object
implements Handler<T>

Abstract base class for Handlers to extend to inherit functionality common across serialization strategies.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.calcite.avatica.remote.Handler

Handler.HandlerResponse<T>

Field Summary

Fields

Modifier and Type	Field and Description
private Service.RpcMetadataResponse	metadata
private static String	NULL_EXCEPTION_MESSAGE
protected Service	service

Fields inherited from interface org.apache.calcite.avatica.remote.Handler

HTTP_INTERNAL_SERVER_ERROR, HTTP_OK

Constructor Summary

Constructors

Constructor and Description
AbstractHandler(Service service)

Method Summary

Methods

Modifier and Type	Method and Description
Handler.HandlerResponse<T>	apply(T serializedRequest) Compute a response for the given request, handling errors generated by that computation.
(package private) abstract Service.Request	decode(T serializedRequest)
(package private) abstract T	encode(Service.Response response) Serialize the given Service.Response per the concrete Handler implementation.
private String	getCausalChain(Exception e) Constructs a message for the summary of an Exception.
void	setRpcMetadata(Service.RpcMetadataResponse metadata) Sets some general server information to return to the client in all responses.
(package private) Service.ErrorResponse	unwrapException(Exception e) Unwrap Avatica-specific context about a given exception.

Methods inherited from class java.lang.Object

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

Field Detail

NULL_EXCEPTION_MESSAGE

private static final String NULL_EXCEPTION_MESSAGE

See Also:

Constant Field Values

service

protected final Service service

metadata

private Service.RpcMetadataResponse metadata

Constructor Detail

AbstractHandler

public AbstractHandler(Service service)

Method Detail

decode

abstract Service.Request decode(T serializedRequest)
                         throws IOException

Throws:

IOException

encode

abstract T encode(Service.Response response)
           throws IOException

Serialize the given Service.Response per the concrete Handler implementation.

Parameters:

response - The Service.Response to serialize.

Returns:

A serialized representation of the Service.Response.

Throws:

IOException

unwrapException

Service.ErrorResponse unwrapException(Exception e)

Unwrap Avatica-specific context about a given exception.

Parameters:

e - A caught exception throw by Avatica implementation.

Returns:

An Service.ErrorResponse.

apply

public Handler.HandlerResponse<T> apply(T serializedRequest)

Compute a response for the given request, handling errors generated by that computation.

Specified by:

apply in interface Handler<T>

Parameters:

serializedRequest - The caller's request.

Returns:

A Service.Response with additional context about that response.

getCausalChain

private String getCausalChain(Exception e)

Constructs a message for the summary of an Exception.

Parameters:

e - The Exception to summarize.

Returns:

A summary message for the Exception.

setRpcMetadata

public void setRpcMetadata(Service.RpcMetadataResponse metadata)

Description copied from interface: Handler

Sets some general server information to return to the client in all responses.

Specified by:

setRpcMetadata in interface Handler<T>

Parameters:

metadata - Server-wide information