com.bigdata.service.IFederationDelegate Maven / Gradle / Ivy
/*
Copyright (C) SYSTAP, LLC DBA Blazegraph 2006-2016. All rights reserved.
Contact:
SYSTAP, LLC DBA Blazegraph
2501 Calvert ST NW #106
Washington, DC 20008
[email protected]
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
* Created on Sep 17, 2008
*/
package com.bigdata.service;
import java.io.IOException;
import java.util.UUID;
import com.bigdata.counters.CounterSet;
import com.bigdata.counters.ICounterSetAccess;
import com.bigdata.counters.httpd.CounterSetHTTPD;
import com.bigdata.util.httpd.AbstractHTTPD;
/**
* Interface allowing services to take over handling of events normally handled
* by the {@link AbstractFederation}.
*
* @author Bryan Thompson
* @version $Id$
* @param
* The generic type of the client or service.
*/
public interface IFederationDelegate {
/**
* Return the client or service.
*/
public T getService();
/**
* Return a name for the service. It is up to administrators to ensure that
* service names are unique.
*
* @return A name for the service.
*/
public String getServiceName();
/**
* Return the class or interface that is the most interesting facet of the
* client and which will be used to identify this client in the performance
* counters reported to the {@link ILoadBalancerService}.
*
* @return The class or interface and never null.
*/
public Class getServiceIface();
/**
* The {@link UUID} assigned to the {@link IBigdataClient} or
* {@link AbstractService}.
*
* @see AbstractService#setServiceUUID(UUID)
*/
public UUID getServiceUUID();
/**
* Offers the service an opportunity to dynamically detach and re-attach
* performance counters. This can be invoked either in response to an http
* GET or the periodic reporting of performance counters to the
* {@link ILoadBalancerService}. In general, implementations should limit
* the frequency of update, e.g., to no more than once a second.
*
* Note: For most purposes, this has been replaced by
* {@link ICounterSetAccess} which is now passed into
* {@link CounterSetHTTPD}. That provides the necessary indirection for
* periodic refresh of the performance counters. The {@link CounterSetHTTPD}
* now also handles the limitation on the update frequency for the
* materialized counters.
*
* However, there are still some counters which need to be dynamically
* reattached. For example, any counter set which is dynamic in its
* structure, such as the DirectBufferPool.
*/
public void reattachDynamicCounters();
/**
* Return true iff the service is ready to start.
*/
public boolean isServiceReady();
/**
* Invoked by the {@link AbstractFederation} once the deferred startup tasks
* are executed. Services may use this event to perform additional
* initialization.
*/
public void didStart();
/**
* Notice that the service has been discovered. This notice will be
* generated the first time the service is discovered by a given
* {@link IBigdataClient}.
*
* @param service
* The service.
* @param serviceUUID
* The service {@link UUID}.
*/
public void serviceJoin(IService service, UUID serviceUUID);
/**
* Notice that the service is no longer available. This notice will be
* generated once for a given {@link IBigdataClient} when the service is no
* longer available from any of its service registrars.
*
* @param serviceUUID
* The service {@link UUID}.
*/
public void serviceLeave(UUID serviceUUID);
/**
* Create a new {@link AbstractHTTPD} instance.
*
* @param port
* The port, or zero for a random port.
* @param access
* Used to materialize the {@link CounterSet} that will be served
* up.
*
* @return The httpd daemon.
*
* @throws IOException
*/
public AbstractHTTPD newHttpd(final int httpdPort,
final ICounterSetAccess access) throws IOException;
}