com.r3corda.node.services.transactions / NotaryService

# NotaryService

`abstract class NotaryService : AbstractNodeService`

A Notary service acts as the final signer of a transaction ensuring two things:

- The (optional) timestamp of the transaction is valid.

- None of the referenced input states have previously been consumed by a transaction signed by this Notary

A transaction has to be signed by a Notary to be considered valid (except for output-only transactions without a timestamp).

This is the base implementation that can be customised with specific Notary transaction commit protocol.

### Types

Type | `object Type : ServiceType`

### Constructors

<init> | `NotaryService(smm: StateMachineManager, net: MessagingService, timestampChecker: TimestampChecker, uniquenessProvider: UniquenessProvider, networkMapCache: NetworkMapCache)` A Notary service acts as the final signer of a transaction ensuring two things:

### Properties

logger | `abstract val logger: <ERROR CLASS>`
protocolFactory | `abstract val protocolFactory: Factory` Implement a factory that specifies the transaction commit protocol for the notary service to use
smm | `val smm: StateMachineManager`
timestampChecker | `val timestampChecker: TimestampChecker`
uniquenessProvider | `val uniquenessProvider: UniquenessProvider`

### Inherited Properties

net | `val net: MessagingService`
networkMapCache | `val networkMapCache: NetworkMapCache`

### Inherited Functions

addMessageHandler | `fun <Q : ServiceRequestMessage, R : Any> addMessageHandler(topic: String, handler: (Q) -> R, exceptionConsumer: (Message, Exception) -> Unit): Unit` Register a handler for a message topic. In comparison to using net.addMessageHandler() this manages a lot of common boilerplate code. Exceptions are caught and passed to the provided consumer. If you just want a simple acknowledgement response with no content, use com.r3corda.core.messaging.Ack. `fun <Q : ServiceRequestMessage, R : Any> addMessageHandler(topic: String, handler: (Q) -> R): Unit` Register a handler for a message topic. In comparison to using net.addMessageHandler() this manages a lot of common boilerplate code. Exceptions are propagated to the messaging layer. If you just want a simple acknowledgement response with no content, use com.r3corda.core.messaging.Ack.

### Inheritors

SimpleNotaryService | `class SimpleNotaryService : NotaryService` A simple Notary service that does not perform transaction validation
ValidatingNotaryService | `class ValidatingNotaryService : NotaryService` A Notary service that validates the transaction chain of he submitted transaction before committing it