Package com.rabbitmq.tools.jsonrpc

Class JsonRpcClient

java.lang.Object

com.rabbitmq.client.RpcClient

com.rabbitmq.tools.jsonrpc.JsonRpcClient

All Implemented Interfaces:

java.lang.AutoCloseable, java.lang.reflect.InvocationHandler

public class JsonRpcClient
extends RpcClient
implements java.lang.reflect.InvocationHandler

JSON-RPC is a lightweight RPC mechanism using JSON as a data language for request and reply messages. It is rapidly becoming a standard in web development, where it is used to make RPC requests over HTTP. RabbitMQ provides an AMQP transport binding for JSON-RPC in the form of the JsonRpcClient class.

JSON-RPC services are self-describing - each service is able to list its supported procedures, and each procedure describes its parameters and types. An instance of JsonRpcClient retrieves its service description using the standard system.describe procedure when it is constructed, and uses the information to coerce parameter types appropriately. A JSON service description is parsed into instances of ServiceDescription. Client code can access the service description by reading the serviceDescription field of JsonRpcClient instances.

JsonRpcClient delegates JSON parsing and generating to a JsonRpcMapper.

See Also:

call(String, Object[]), JsonRpcMapper, JacksonJsonRpcMapper

Nested Class Summary

Nested classes/interfaces inherited from class com.rabbitmq.client.RpcClient

RpcClient.Response

Field Summary

Fields

Modifier and Type	Field	Description
private static org.slf4j.Logger	LOGGER
private JsonRpcMapper	mapper
private ServiceDescription	serviceDescription	Holds the JSON-RPC service description for this client.

Fields inherited from class com.rabbitmq.client.RpcClient

DEFAULT_REPLY_HANDLER, NO_TIMEOUT

Constructor Summary

Constructors

Constructor	Description
JsonRpcClient(Channel channel, java.lang.String exchange, java.lang.String routingKey)
JsonRpcClient(Channel channel, java.lang.String exchange, java.lang.String routingKey, int timeout)	Construct a new JsonRpcClient, passing the parameters through to RpcClient's constructor.
JsonRpcClient(Channel channel, java.lang.String exchange, java.lang.String routingKey, int timeout, JsonRpcMapper mapper)	Construct a new JsonRpcClient, passing the parameters through to RpcClient's constructor.
JsonRpcClient(RpcClientParams rpcClientParams, JsonRpcMapper mapper)	Construct a new JsonRpcClient, passing the RpcClientParams through RpcClient's constructor.

Method Summary

Modifier and Type	Method	Description
java.lang.Object	call(java.lang.String[] args)	Deprecated. This method will be removed in the next major version
java.lang.Object	call(java.lang.String method, java.lang.Object[] params)	Public API - builds, encodes and sends a JSON-RPC request, and waits for the response.
private java.lang.Object	checkReply(JsonRpcMapper.JsonRpcResponse reply)	Private API - parses a JSON-RPC reply object, checking it for exceptions.
static java.lang.Object	coerce(java.lang.String val, java.lang.String type)	Deprecated. This method will be removed in the next major version
<T> T	createProxy(java.lang.Class<T> klass)	Public API - gets a dynamic proxy for a particular interface class.
ServiceDescription	getServiceDescription()	Public API - gets the service description record that this service loaded from the server itself at construction time.
java.lang.Object	invoke(java.lang.Object proxy, java.lang.reflect.Method method, java.lang.Object[] args)	Public API - implements InvocationHandler.invoke.
private void	retrieveServiceDescription()	Private API - invokes the "system.describe" method on the server, and parses and stores the resulting service description in this object.

Methods inherited from class com.rabbitmq.client.RpcClient

close, doCall, doCall, getChannel, getConsumer, getContinuationMap, getCorrelationId, getExchange, getRoutingKey, incrementingCorrelationIdSupplier, incrementingCorrelationIdSupplier, mapCall, mapCall, primitiveCall, primitiveCall, primitiveCall, publish, responseCall, responseCall, setupConsumer, stringCall

Methods inherited from class java.lang.Object

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

Field Detail

LOGGER

private static final org.slf4j.Logger LOGGER

mapper

private final JsonRpcMapper mapper

serviceDescription

private ServiceDescription serviceDescription

Holds the JSON-RPC service description for this client.

Constructor Detail

JsonRpcClient

public JsonRpcClient(RpcClientParams rpcClientParams,
                     JsonRpcMapper mapper)
              throws java.io.IOException,
                     JsonRpcException,
                     java.util.concurrent.TimeoutException

Construct a new JsonRpcClient, passing the RpcClientParams through RpcClient's constructor.

The service description record is retrieved from the server during construction.

Parameters:

rpcClientParams -

mapper -

Throws:

java.io.IOException

JsonRpcException

java.util.concurrent.TimeoutException

JsonRpcClient

public JsonRpcClient(Channel channel,
                     java.lang.String exchange,
                     java.lang.String routingKey,
                     int timeout,
                     JsonRpcMapper mapper)
              throws java.io.IOException,
                     JsonRpcException,
                     java.util.concurrent.TimeoutException

Construct a new JsonRpcClient, passing the parameters through to RpcClient's constructor. The service description record is retrieved from the server during construction.

Throws:

java.util.concurrent.TimeoutException - if a response is not received within the timeout specified, if any

java.io.IOException

JsonRpcException

JsonRpcClient

public JsonRpcClient(Channel channel,
                     java.lang.String exchange,
                     java.lang.String routingKey,
                     int timeout)
              throws java.io.IOException,
                     JsonRpcException,
                     java.util.concurrent.TimeoutException

Construct a new JsonRpcClient, passing the parameters through to RpcClient's constructor. The service description record is retrieved from the server during construction.

Throws:

java.util.concurrent.TimeoutException - if a response is not received within the timeout specified, if any

java.io.IOException

JsonRpcException

JsonRpcClient

public JsonRpcClient(Channel channel,
                     java.lang.String exchange,
                     java.lang.String routingKey)
              throws java.io.IOException,
                     JsonRpcException,
                     java.util.concurrent.TimeoutException

Throws:

java.io.IOException

JsonRpcException

java.util.concurrent.TimeoutException

Method Detail

coerce

@Deprecated
public static java.lang.Object coerce(java.lang.String val,
                                      java.lang.String type)
                               throws java.lang.NumberFormatException

Deprecated.

This method will be removed in the next major version

Private API - used by call(String[]) to ad-hoc convert strings into the required data types for a call. This method is deprecated because it uses homegrown JSON utilities that don't deal correctly with complex types. The JacksonJsonRpcMapper has been introduced to handle primitive and complex types, as well as primitive wrappers correctly.

Throws:

java.lang.NumberFormatException

checkReply

private java.lang.Object checkReply(JsonRpcMapper.JsonRpcResponse reply)
                             throws JsonRpcException

Private API - parses a JSON-RPC reply object, checking it for exceptions.

Returns:

the result contained within the reply, if no exception is found Throws JsonRpcException if the reply object contained an exception

Throws:

JsonRpcException

call

public java.lang.Object call(java.lang.String method,
                             java.lang.Object[] params)
                      throws java.io.IOException,
                             JsonRpcException,
                             java.util.concurrent.TimeoutException

Public API - builds, encodes and sends a JSON-RPC request, and waits for the response.

Returns:

the result contained within the reply, if no exception is found

Throws:

JsonRpcException - if the reply object contained an exception

java.util.concurrent.TimeoutException - if a response is not received within the timeout specified, if any

java.io.IOException

invoke

public java.lang.Object invoke(java.lang.Object proxy,
                               java.lang.reflect.Method method,
                               java.lang.Object[] args)
                        throws java.lang.Throwable

Public API - implements InvocationHandler.invoke. This is useful for constructing dynamic proxies for JSON-RPC interfaces.

Specified by:

invoke in interface java.lang.reflect.InvocationHandler

Throws:

java.lang.Throwable

createProxy

public <T> T createProxy(java.lang.Class<T> klass)
                  throws java.lang.IllegalArgumentException

Public API - gets a dynamic proxy for a particular interface class.

Throws:

java.lang.IllegalArgumentException

call

@Deprecated
public java.lang.Object call(java.lang.String[] args)
                      throws java.lang.NumberFormatException,
                             java.io.IOException,
                             JsonRpcException,
                             java.util.concurrent.TimeoutException

Deprecated.

This method will be removed in the next major version

Public API - as call(String, Object[]), but takes the method name from the first entry in args, and the parameters from subsequent entries. All parameter values are passed through coerce() to attempt to make them the types the server is expecting. This method is deprecated because it uses homegrown JSON utilities that don't deal correctly with complex types. The JacksonJsonRpcMapper has been introduced to handle primitive and complex types, as well as primitive wrappers correctly.

Returns:

the result contained within the reply, if no exception is found

Throws:

JsonRpcException - if the reply object contained an exception

java.lang.NumberFormatException - if a coercion failed

java.util.concurrent.TimeoutException - if a response is not received within the timeout specified, if any

java.io.IOException

See Also:

coerce(java.lang.String, java.lang.String)

getServiceDescription

public ServiceDescription getServiceDescription()

Public API - gets the service description record that this service loaded from the server itself at construction time.

retrieveServiceDescription

private void retrieveServiceDescription()
                                 throws java.io.IOException,
                                        JsonRpcException,
                                        java.util.concurrent.TimeoutException

Private API - invokes the "system.describe" method on the server, and parses and stores the resulting service description in this object. TODO: Avoid calling this from the constructor.

Throws:

java.util.concurrent.TimeoutException - if a response is not received within the timeout specified, if any

java.io.IOException

JsonRpcException