com.exonum.binding.core.service

Class AbstractService

java.lang.Object

com.exonum.binding.core.service.AbstractService

All Implemented Interfaces:

Service

public abstract class AbstractService
extends Object
implements Service

A base class for user services.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractService(ServiceInstanceSpec instanceSpec)

Method Summary

Modifier and Type	Method and Description
protected abstract Schema	createDataSchema(View view) Creates a data schema of this service.
protected int	getId() Returns the numeric id of the service instance.
protected ServiceInstanceSpec	getInstanceSpec() Returns this service instance specification.
protected String	getName() Returns the name of the service instance.
List<com.exonum.binding.common.hash.HashCode>	getStateHashes(Snapshot snapshot) Returns a list of hashes representing the state of this service, as of the given snapshot of the blockchain state.

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.exonum.binding.core.service.Service

afterCommit, beforeCommit, createPublicApiHandlers, initialize

Constructor Detail

AbstractService

protected AbstractService(ServiceInstanceSpec instanceSpec)

Method Detail

getName

protected final String getName()

Returns the name of the service instance.

See Also:

ServiceInstanceSpec.getName()

getId

protected final int getId()

Returns the numeric id of the service instance.

See Also:

ServiceInstanceSpec.getId()

getInstanceSpec

protected final ServiceInstanceSpec getInstanceSpec()

Returns this service instance specification.

getStateHashes

public List<com.exonum.binding.common.hash.HashCode> getStateHashes(Snapshot snapshot)

Description copied from interface: Service

Returns a list of hashes representing the state of this service, as of the given snapshot of the blockchain state. Usually, it includes the hashes of all Merkelized collections defined by this service.

The core uses this list to verify that the service on each node in the network has the same database state. To do so efficiently, it aggregates state hashes of all services into a single Merkelized meta-map. The hash of this meta-map is considered the hash of the entire blockchain state and is recorded as such in blocks and Precommit messages.

Please note that if this service does not provide any state hashes, the framework will not be able to verify that its transactions cause the same results on different nodes.

Specified by:

getStateHashes in interface Service

Parameters:

snapshot - a snapshot of the blockchain state. Not valid after this method returns

See Also:

ProofListIndexProxy.getIndexHash(), ProofMapIndexProxy.getIndexHash()

createDataSchema

protected abstract Schema createDataSchema(View view)

Creates a data schema of this service.

Parameters:

view - a database view

Returns:

a data schema of the service