io.vertx.servicediscovery

Interface ServiceDiscovery

public interface ServiceDiscovery

Service Discovery main entry point.

The service discovery is an infrastructure that let you publish and find `services`. A `service` is a discoverable functionality. It can be qualified by its type, metadata, and location. So a `service` can be a database, a service proxy, a HTTP endpoint. It does not have to be a vert.x entity, but can be anything. Each service is described by a Record.

The service discovery implements the interactions defined in the service-oriented computing. And to some extend, also provides the dynamic service-oriented computing interaction. So, application can react to arrival and departure of services.

A service provider can:

* publish a service record * un-publish a published record * update the status of a published service (down, out of service...)

A service consumer can:

* lookup for services * bind to a selected service (it gets a ServiceReference) and use it * release the service once the consumer is done with it * listen for arrival, departure and modification of services.

Consumer would 1) lookup for service record matching their need, 2) retrieve the ServiceReference that give access to the service, 3) get a service object to access the service, 4) release the service object once done.

A state above, the central piece of information shared by the providers and consumers are records.

Providers and consumers must create their own ServiceDiscovery instance. These instances are collaborating in background (distributed structure) to keep the set of services in sync.

Author:

Clement Escoffier

Method Summary

Modifier and Type	Method and Description
Set<ServiceReference>	bindings()
void	close() Closes the service discovery
static ServiceDiscovery	create(Vertx vertx) Creates a new instance of ServiceDiscovery using the default configuration.
static ServiceDiscovery	create(Vertx vertx, Handler<ServiceDiscovery> completionHandler) Deprecated. this will be removed in Vert.x 4, instead use create(Vertx)
static ServiceDiscovery	create(Vertx vertx, ServiceDiscoveryOptions options) Creates an instance of ServiceDiscovery.
static ServiceDiscovery	create(Vertx vertx, ServiceDiscoveryOptions options, Handler<ServiceDiscovery> completionHandler) Deprecated. this will be removed in Vert.x 4, instead use create(Vertx, ServiceDiscoveryOptions)
void	getRecord(java.util.function.Function<Record,Boolean> filter, boolean includeOutOfService, Handler<AsyncResult<Record>> resultHandler) Lookups for a single record.
void	getRecord(java.util.function.Function<Record,Boolean> filter, Handler<AsyncResult<Record>> resultHandler) Lookups for a single record.
void	getRecord(JsonObject filter, Handler<AsyncResult<Record>> resultHandler) Lookups for a single record.
void	getRecords(java.util.function.Function<Record,Boolean> filter, boolean includeOutOfService, Handler<AsyncResult<List<Record>>> resultHandler) Lookups for a set of records.
void	getRecords(java.util.function.Function<Record,Boolean> filter, Handler<AsyncResult<List<Record>>> resultHandler) Lookups for a set of records.
void	getRecords(JsonObject filter, Handler<AsyncResult<List<Record>>> resultHandler) Lookups for a set of records.
ServiceReference	getReference(Record record) Gets a service reference from the given record.
ServiceReference	getReferenceWithConfiguration(Record record, JsonObject configuration) Gets a service reference from the given record, the reference is configured with the given json object.
ServiceDiscoveryOptions	options()
void	publish(Record record, Handler<AsyncResult<Record>> resultHandler) Publishes a record.
ServiceDiscovery	registerServiceExporter(ServiceExporter exporter, JsonObject configuration) Registers a discovery bridge.
ServiceDiscovery	registerServiceExporter(ServiceExporter exporter, JsonObject configuration, Handler<AsyncResult<Void>> completionHandler) Registers a discovery bridge.
ServiceDiscovery	registerServiceImporter(ServiceImporter importer, JsonObject configuration) Registers a discovery service importer.
ServiceDiscovery	registerServiceImporter(ServiceImporter importer, JsonObject configuration, Handler<AsyncResult<Void>> completionHandler) Registers a discovery service importer.
boolean	release(ServiceReference reference) Releases the service reference.
static void	releaseServiceObject(ServiceDiscovery discovery, Object svcObject) Release the service object retrieved using get methods from the service type interface.
void	unpublish(String id, Handler<AsyncResult<Void>> resultHandler) Un-publishes a record.
void	update(Record record, Handler<AsyncResult<Record>> resultHandler) Updates the given record.

Method Detail

create

static ServiceDiscovery create(Vertx vertx,
                               ServiceDiscoveryOptions options)

Creates an instance of ServiceDiscovery.

Parameters:

vertx - the vert.x instance

options - the discovery options

Returns:

the created service discovery instance.

create

static ServiceDiscovery create(Vertx vertx)

Creates a new instance of ServiceDiscovery using the default configuration.

Parameters:

vertx - the vert.x instance

Returns:

the created instance

create

@Deprecated
static ServiceDiscovery create(Vertx vertx,
                                           ServiceDiscoveryOptions options,
                                           Handler<ServiceDiscovery> completionHandler)

Deprecated. this will be removed in Vert.x 4, instead use create(Vertx, ServiceDiscoveryOptions)

Creates an instance of ServiceDiscovery.

Parameters:

vertx - the vert.x instance

options - the discovery options

completionHandler - completion handler called when the service discovery has been initialized. This includes the initialization of the service importer registered from the SPI.

Returns:

the created instance, should not be used to retrieve services before the invocation of the completion handler.

create

@Deprecated
static ServiceDiscovery create(Vertx vertx,
                                           Handler<ServiceDiscovery> completionHandler)

Deprecated. this will be removed in Vert.x 4, instead use create(Vertx)

Creates a new instance of ServiceDiscovery using the default configuration.

Parameters:

vertx - the vert.x instance

completionHandler - completion handler called when the service discovery has been initialized. This includes the initialization of the service importer registered from the SPI.

Returns:

the created instance, should not be used to retrieve services before the invocation of the completion handler.

getReference

ServiceReference getReference(Record record)

Gets a service reference from the given record.

Parameters:

record - the chosen record

Returns:

the service reference, that allows retrieving the service object. Once called the service reference is cached, and need to be released.

getReferenceWithConfiguration

ServiceReference getReferenceWithConfiguration(Record record,
                                               JsonObject configuration)

Gets a service reference from the given record, the reference is configured with the given json object.

Parameters:

record - the chosen record

configuration - the configuration

Returns:

the service reference, that allows retrieving the service object. Once called the service reference is cached, and need to be released.

release

boolean release(ServiceReference reference)

Releases the service reference.

Parameters:

reference - the reference to release, must not be null

Returns:

whether or not the reference has been released.

registerServiceImporter

ServiceDiscovery registerServiceImporter(ServiceImporter importer,
                                         JsonObject configuration)

Registers a discovery service importer. Importers let you integrate other discovery technologies in this service discovery.

Parameters:

importer - the service importer

configuration - the optional configuration

Returns:

the current ServiceDiscovery

registerServiceImporter

ServiceDiscovery registerServiceImporter(ServiceImporter importer,
                                         JsonObject configuration,
                                         Handler<AsyncResult<Void>> completionHandler)

Registers a discovery service importer. Importers let you integrate other discovery technologies in this service discovery.

Parameters:

importer - the service importer

configuration - the optional configuration

completionHandler - handler call when the importer has finished its initialization and initial imports

Returns:

the current ServiceDiscovery

registerServiceExporter

ServiceDiscovery registerServiceExporter(ServiceExporter exporter,
                                         JsonObject configuration)

Registers a discovery bridge. Exporters let you integrate other discovery technologies in this service discovery.

Parameters:

exporter - the service exporter

configuration - the optional configuration

Returns:

the current ServiceDiscovery

registerServiceExporter

ServiceDiscovery registerServiceExporter(ServiceExporter exporter,
                                         JsonObject configuration,
                                         Handler<AsyncResult<Void>> completionHandler)

Registers a discovery bridge. Exporters let you integrate other discovery technologies in this service discovery.

Parameters:

exporter - the service exporter

configuration - the optional configuration

completionHandler - handler notified when the exporter has been correctly initialized.

Returns:

the current ServiceDiscovery

close

void close()

Closes the service discovery

publish

void publish(Record record,
             Handler<AsyncResult<Record>> resultHandler)

Publishes a record.

Parameters:

record - the record

resultHandler - handler called when the operation has completed (successfully or not). In case of success, the passed record has a registration id required to modify and un-register the service.

unpublish

void unpublish(String id,
               Handler<AsyncResult<Void>> resultHandler)

Un-publishes a record.

Parameters:

id - the registration id

resultHandler - handler called when the operation has completed (successfully or not).

getRecord

void getRecord(JsonObject filter,
               Handler<AsyncResult<Record>> resultHandler)

Lookups for a single record.

Filters are expressed using a Json object. Each entry of the given filter will be checked against the record. All entry must match exactly the record. The entry can use the special "*" value to denotes a requirement on the key, but not on the value.

Let's take some example:

   { "name" = "a" } => matches records with name set fo "a"
   { "color" = "*" } => matches records with "color" set
   { "color" = "red" } => only matches records with "color" set to "red"
   { "color" = "red", "name" = "a"} => only matches records with name set to "a", and color set to "red"
 

If the filter is not set (null or empty), it accepts all records.

This method returns the first matching record.

Parameters:

filter - the filter.

resultHandler - handler called when the lookup has been completed. When there are no matching record, the operation succeeds, but the async result has no result (null).

getRecord

void getRecord(java.util.function.Function<Record,Boolean> filter,
               Handler<AsyncResult<Record>> resultHandler)

Lookups for a single record.

The filter is a Function taking a Record as argument and returning a boolean. You should see it as an accept method of a filter. This method return a record passing the filter.

This method only looks for records with a UP status.

Parameters:

filter - the filter, must not be null. To return all records, use a function accepting all records

resultHandler - the result handler called when the lookup has been completed. When there are no matching record, the operation succeed, but the async result has no result.

getRecord

void getRecord(java.util.function.Function<Record,Boolean> filter,
               boolean includeOutOfService,
               Handler<AsyncResult<Record>> resultHandler)

Lookups for a single record.

The filter is a Function taking a Record as argument and returning a boolean. You should see it as an accept method of a filter. This method return a record passing the filter.

Unlike getRecord(Function, Handler), this method may accept records with a OUT OF SERVICE status, if the includeOutOfService parameter is set to true.

Parameters:

filter - the filter, must not be null. To return all records, use a function accepting all records

includeOutOfService - whether or not the filter accepts OUT OF SERVICE records

resultHandler - the result handler called when the lookup has been completed. When there are no matching record, the operation succeed, but the async result has no result.

getRecords

void getRecords(JsonObject filter,
                Handler<AsyncResult<List<Record>>> resultHandler)

Lookups for a set of records. Unlike getRecord(JsonObject, Handler), this method returns all matching records.

Parameters:

filter - the filter - see getRecord(JsonObject, Handler)

resultHandler - handler called when the lookup has been completed. When there are no matching record, the operation succeed, but the async result has an empty list as result.

getRecords

void getRecords(java.util.function.Function<Record,Boolean> filter,
                Handler<AsyncResult<List<Record>>> resultHandler)

Lookups for a set of records. Unlike getRecord(Function, Handler), this method returns all matching records.

The filter is a Function taking a Record as argument and returning a boolean. You should see it as an accept method of a filter. This method return a record passing the filter.

This method only looks for records with a UP status.

Parameters:

filter - the filter, must not be null. To return all records, use a function accepting all records

resultHandler - handler called when the lookup has been completed. When there are no matching record, the operation succeed, but the async result has an empty list as result.

getRecords

void getRecords(java.util.function.Function<Record,Boolean> filter,
                boolean includeOutOfService,
                Handler<AsyncResult<List<Record>>> resultHandler)

Lookups for a set of records. Unlike getRecord(Function, Handler), this method returns all matching records.

The filter is a Function taking a Record as argument and returning a boolean. You should see it as an accept method of a filter. This method return a record passing the filter.

Unlike getRecords(Function, Handler), this method may accept records with a OUT OF SERVICE status, if the includeOutOfService parameter is set to true.

Parameters:

filter - the filter, must not be null. To return all records, use a function accepting all records

includeOutOfService - whether or not the filter accepts OUT OF SERVICE records

resultHandler - handler called when the lookup has been completed. When there are no matching record, the operation succeed, but the async result has an empty list as result.

update

void update(Record record,
            Handler<AsyncResult<Record>> resultHandler)

Updates the given record. The record must has been published, and has it's registration id set.

Parameters:

record - the updated record

resultHandler - handler called when the lookup has been completed.

bindings

Set<ServiceReference> bindings()

Returns:

the set of service references retrieved by this service discovery.

options

ServiceDiscoveryOptions options()

Returns:

the discovery options. Modifying the returned object would not update the discovery service configuration. This object should be considered as read-only.

releaseServiceObject

static void releaseServiceObject(ServiceDiscovery discovery,
                                 Object svcObject)

Release the service object retrieved using get methods from the service type interface. It searches for the reference associated with the given object and release it.

Parameters:

discovery - the service discovery

svcObject - the service object