org.apache.nifi.remote.client

Interface SiteToSiteClient

All Superinterfaces:

AutoCloseable, Closeable

All Known Implementing Classes:

AbstractSiteToSiteClient, HttpClient, SocketClient

public interface SiteToSiteClient
extends Closeable

The SiteToSiteClient provides a mechanism for sending data to a remote instance of NiFi (or NiFi cluster) and retrieving data from a remote instance of NiFi (or NiFi cluster).

When configuring the client via the SiteToSiteClient.Builder, the Builder must be provided the URL of the remote NiFi instance. If the URL points to a standalone instance of NiFi, all interaction will take place with that instance of NiFi. However, if the URL points to the NiFi Cluster Manager of a cluster, the client will automatically handle load balancing the transactions across the different nodes in the cluster.

The SiteToSiteClient provides a Transaction through which all interaction with the remote instance takes place. After data has been exchanged or it is determined that no data is available, the Transaction can then be canceled (via the Transaction.cancel(String) method) or can be completed (via the Transaction.complete() method).

An instance of SiteToSiteClient can be obtained by constructing a new instance of the SiteToSiteClient.Builder class, calling the appropriate methods to configured the client as desired, and then calling the build() method.

The SiteToSiteClient itself is immutable once constructed and is thread-safe. Many threads can share access to the same client. However, the Transaction that is created by the client is not thread safe and should not be shared among threads.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	SiteToSiteClient.Builder The Builder is the mechanism by which all configuration is passed to the SiteToSiteClient.
static class	SiteToSiteClient.StandardSiteToSiteClientConfig

Method Summary

Modifier and Type	Method and Description
Transaction	createTransaction(TransferDirection direction) Creates a new Transaction that can be used to either send data to a remote NiFi instance or receive data from a remote NiFi instance, depending on the value passed for the direction argument.
SiteToSiteClientConfig	getConfig()
boolean	isSecure() In order to determine whether the server is configured for secure communications, the client may have to query the server's RESTful interface.

Methods inherited from interface java.io.Closeable

close

Method Detail

createTransaction

Transaction createTransaction(TransferDirection direction)
                       throws HandshakeException,
                              PortNotRunningException,
                              ProtocolException,
                              UnknownPortException,
                              IOException

Creates a new Transaction that can be used to either send data to a remote NiFi instance or receive data from a remote NiFi instance, depending on the value passed for the direction argument.

Note: If all of the nodes are penalized (See SiteToSiteClient.Builder.nodePenalizationPeriod(long, TimeUnit)), then this method will return null.

Parameters:

direction - specifies which direction the data should be transferred. A value of TransferDirection.SEND indicates that this Transaction will send data to the remote instance; a value of TransferDirection.RECEIVE indicates that this Transaction will be used to receive data from the remote instance.

Returns:

a Transaction to use for sending or receiving data, or null if all nodes are penalized.

Throws:

HandshakeException - he

PortNotRunningException - pnre

IOException - ioe

UnknownPortException - upe

ProtocolException

isSecure

boolean isSecure()
          throws IOException

In order to determine whether the server is configured for secure communications, the client may have to query the server's RESTful interface. Doing so could result in an IOException.

Returns:

true if site-to-site communications with the remote instance are secure, false if site-to-site communications with the remote instance are not secure. Whether or not communications are secure depends on the server, not the client

Throws:

IOException - if unable to query the remote instance's RESTful interface or if the remote instance is not configured to allow site-to-site communications

getConfig

SiteToSiteClientConfig getConfig()

Returns:

the configuration object that was built by the Builder