Package org.apache.cayenne.remote

Class ClientChannel

java.lang.Object

org.apache.cayenne.remote.ClientChannel

All Implemented Interfaces:

DataChannel

public class ClientChannel
extends Object
implements DataChannel

A DataChannel implementation that accesses a remote server via a ClientConnection.

Since:

1.2

Field Summary

Fields

Modifier and Type	Field	Description
protected boolean	channelEventsEnabled
protected ClientConnection	connection
protected GraphDiffCompressor	diffCompressor
protected EntityResolver	entityResolver
protected EventManager	eventManager

Fields inherited from interface org.apache.cayenne.DataChannel

FLUSH_CASCADE_SYNC, FLUSH_NOCASCADE_SYNC, GRAPH_CHANGED_SUBJECT, GRAPH_FLUSHED_SUBJECT, GRAPH_ROLLEDBACK_SUBJECT, ROLLBACK_CASCADE_SYNC

Constructor Summary

Constructors

Constructor	Description
ClientChannel(ClientConnection connection, boolean channelEventsEnabled, EventManager eventManager, boolean remoteEventsOptional)

Method Summary

Modifier and Type	Method	Description
ClientConnection	getConnection()
EntityResolver	getEntityResolver()	Returns EntityResolver obtained from the server.
EventManager	getEventManager()	Returns an EventManager associated with this channel.
boolean	isChannelEventsEnabled()
QueryResponse	onQuery(ObjectContext context, Query query)	Executes a query, using provided context to register persistent objects if query returns any objects.
GraphDiff	onSync(ObjectContext originatingContext, GraphDiff changes, int syncType)	Processes synchronization request from a child ObjectContext, returning a GraphDiff that describes changes to objects made on the receiving end as a result of synchronization.
protected <T> T	send(org.apache.cayenne.remote.ClientMessage message, Class<T> resultClass)	Sends a message via connector, getting a result as an instance of a specific class.
protected boolean	setupRemoteChannelListener()	Starts up an EventBridge to listen for remote updates.

Methods inherited from class java.lang.Object

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

Field Details

connection

protected ClientConnection connection

eventManager

protected EventManager eventManager

entityResolver

protected EntityResolver entityResolver

channelEventsEnabled

protected boolean channelEventsEnabled

diffCompressor

protected GraphDiffCompressor diffCompressor

Constructor Details

ClientChannel

public ClientChannel(ClientConnection connection,
 boolean channelEventsEnabled,
 EventManager eventManager,
 boolean remoteEventsOptional)
              throws CayenneRuntimeException

Parameters:

remoteEventsOptional - if true, failure to start an EventBridge will not result in an exception.

Throws:

CayenneRuntimeException

Since:

3.0

Method Details

getConnection

public ClientConnection getConnection()

Since:

3.1

isChannelEventsEnabled

public boolean isChannelEventsEnabled()

Since:

3.1

getEventManager

public EventManager getEventManager()

Description copied from interface: DataChannel

Returns an EventManager associated with this channel. Channel may return null if EventManager is not available for any reason.

Specified by:

getEventManager in interface DataChannel

onQuery

public QueryResponse onQuery(ObjectContext context,
 Query query)

Description copied from interface: DataChannel

Executes a query, using provided context to register persistent objects if query returns any objects.

Specified by:

onQuery in interface DataChannel

Parameters:

context - an ObjectContext that originated the query, used to register result objects.

Returns:

a generic response object that encapsulates result of the execution.

onSync

public GraphDiff onSync(ObjectContext originatingContext,
 GraphDiff changes,
 int syncType)

Description copied from interface: DataChannel

Processes synchronization request from a child ObjectContext, returning a GraphDiff that describes changes to objects made on the receiving end as a result of synchronization.

Specified by:

onSync in interface DataChannel

Parameters:

originatingContext - an ObjectContext that initiated the sync. Can be null.

changes - diff from the context that initiated the sync.

syncType - One of DataChannel.FLUSH_NOCASCADE_SYNC, DataChannel.FLUSH_CASCADE_SYNC, DataChannel.ROLLBACK_CASCADE_SYNC.

getEntityResolver

public EntityResolver getEntityResolver()

Returns EntityResolver obtained from the server. On first access, this method sends a message to the server to retrieve the EntityResolver. On subsequent calls locally cached resolver is used.

Specified by:

getEntityResolver in interface DataChannel

setupRemoteChannelListener

protected boolean setupRemoteChannelListener()
                                      throws CayenneRuntimeException

Starts up an EventBridge to listen for remote updates. Returns true if the listener was setup, false if not. False can be returned if the underlying connection doesn't support events of if there is no EventManager available.

Throws:

CayenneRuntimeException

send

protected <T> T send(org.apache.cayenne.remote.ClientMessage message,
 Class<T> resultClass)

Sends a message via connector, getting a result as an instance of a specific class.

Throws:

CayenneRuntimeException - if an underlying connector exception occurred, or a result is not of expected type.