Package com.exonum.binding.service

Class NodeProxy

java.lang.Object

com.exonum.binding.proxy.AbstractNativeProxy

com.exonum.binding.proxy.AbstractCloseableNativeProxy

com.exonum.binding.service.NodeProxy

All Implemented Interfaces:

CloseableNativeProxy, Node, java.lang.AutoCloseable

public final class NodeProxy
extends AbstractCloseableNativeProxy
implements Node

An Exonum node context. Allows to add transactions to Exonum network and get a snapshot of the database state.

Field Summary

Fields inherited from class com.exonum.binding.proxy.AbstractNativeProxy

nativeHandle

Constructor Summary

Constructors

Constructor	Description
NodeProxy(long nativeHandle)	Creates a proxy of a node.

Method Summary

Modifier and Type	Method	Description
protected void	disposeInternal()	Releases any resources owned by this proxy (e.g., the corresponding native object).
com.exonum.binding.common.crypto.PublicKey	getPublicKey()	Returns the service public key of this node.
com.exonum.binding.common.hash.HashCode	submitTransaction(RawTransaction rawTransaction)	Creates a transaction from the given parameters, signs it with the node service key, and then submits it into Exonum network.
<ResultT> ResultT	withSnapshot(java.util.function.Function<Snapshot,ResultT> snapshotFunction)	Performs a given function with a snapshot of the current database state.

Methods inherited from class com.exonum.binding.proxy.AbstractCloseableNativeProxy

close, getNativeHandle

Methods inherited from class com.exonum.binding.proxy.AbstractNativeProxy

isValidHandle

Methods inherited from class java.lang.Object

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

Constructor Detail

NodeProxy

public NodeProxy(long nativeHandle)

Creates a proxy of a node. Native code owns the node, and, therefore, shall destroy the object.

Parameters:

nativeHandle - an implementation-specific reference to a native node

Method Detail

submitTransaction

public com.exonum.binding.common.hash.HashCode submitTransaction(RawTransaction rawTransaction)
                                                          throws InternalServerError

Creates a transaction from the given parameters, signs it with the node service key, and then submits it into Exonum network. This node does not execute the transaction immediately, but broadcasts it to all the nodes in the network. Then each node verifies the transaction and, if it is correct, adds it to the pool of unconfirmed transactions. The transaction is executed later asynchronously.

Incorrect transactions (e.g., the payload of which cannot be deserialized by the target service, or which have unknown message id) are rejected by the network.

Be aware that each node has its own service key pair, therefore invocations of this method on different nodes will produce different transactions.

Specified by:

submitTransaction in interface Node

Parameters:

rawTransaction - transaction parameters to include in transaction message

Returns:

hash of the transaction message created by the framework

Throws:

java.lang.IllegalStateException - if the node proxy is closed

InternalServerError - if this node failed to process the transaction

See Also:

Blockchain.getTxMessages()

withSnapshot

public <ResultT> ResultT withSnapshot(java.util.function.Function<Snapshot,ResultT> snapshotFunction)

Performs a given function with a snapshot of the current database state.

Specified by:

withSnapshot in interface Node

Type Parameters:

ResultT - a type the function returns

Parameters:

snapshotFunction - a function to execute

Returns:

the result of applying the given function to the database state

Throws:

java.lang.IllegalStateException - if the node proxy is closed

getPublicKey

public com.exonum.binding.common.crypto.PublicKey getPublicKey()

Returns the service public key of this node. The corresponding private key is used for signing transactions in Node.submitTransaction(RawTransaction).

This key is stored under "service_public_key" key in the node configuration file.

Specified by:

getPublicKey in interface Node

Throws:

java.lang.IllegalStateException - if the node proxy is closed

disposeInternal

protected void disposeInternal()

Description copied from class: AbstractCloseableNativeProxy

Releases any resources owned by this proxy (e.g., the corresponding native object).

This method is only called once from AbstractCloseableNativeProxy.close() for a valid proxy and shall not be called directly.

Specified by:

disposeInternal in class AbstractCloseableNativeProxy