/*
Copyright (C) SYSTAP, LLC DBA Blazegraph 2006-2016. All rights reserved.
Contact:
SYSTAP, LLC DBA Blazegraph
2501 Calvert ST NW #106
Washington, DC 20008
licenses@blazegraph.com
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 Jun 5, 2009
*/
package com.bigdata.service.ndx;
import java.util.concurrent.Future;
import com.bigdata.btree.IndexMetadata;
import com.bigdata.btree.UnisolatedReadWriteIndex;
import com.bigdata.btree.keys.KVO;
import com.bigdata.btree.proc.AbstractKeyArrayIndexProcedureConstructor;
import com.bigdata.btree.proc.IKeyArrayIndexProcedure;
import com.bigdata.btree.proc.IResultHandler;
import com.bigdata.relation.accesspath.BlockingBuffer;
import com.bigdata.relation.accesspath.IBlockingBuffer;
import com.bigdata.relation.accesspath.IRunnableBuffer;
import com.bigdata.service.AbstractFederation;
import com.bigdata.service.IBigdataFederation;
import com.bigdata.service.ILoadBalancerService;
import com.bigdata.service.Split;
import com.bigdata.service.ndx.pipeline.IDuplicateRemover;
import com.bigdata.service.ndx.pipeline.IndexAsyncWriteStats;
import com.bigdata.service.ndx.pipeline.KVOC;
import com.bigdata.service.ndx.pipeline.KVOLatch;
/**
* Interface for asynchronous writes on scale-out indices.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
* @version $Id$
*/
public interface IAsynchronousWriteBufferFactory {
/**
* Asynchronous write API (streaming writes).
* <p>
* The returned buffer provides a streaming API which is highly efficient.
* The caller writes ordered {@link KVO}[] chunks onto the thread-safe
* {@link BlockingBuffer}. Those chunks are dynamically combined and then
* split into per-index partition chunks which are written on internally
* managed {@link BlockingBuffer}s for each index partition which will be
* touched by a write operation. The splits are slices of ordered chunks for
* a specific index partition. The {@link BlockingBuffer} uses a merge sort
* when it combines ordered chunks so that the combined chunks remain fully
* ordered. Once a chunk is ready, it is re-shaped for the CTOR and sent to
* the target data service using RMI.
* <p>
* Since this API is asynchronous, you will not have synchronous access to
* values returned by asynchronous writes. However, patterns can be created
* using {@link KVOC} and {@link KVOLatch} which provide notification when
* application defined sets of results have become available. Such patterns
* are created by associated the {@link KVOLatch} with the set of results
* and using {@link IResultHandler} and the object reference on the
* {@link KVOC} to capture the side-effect of the write.
* <p>
* {@link BlockingBuffer#getFuture()} may be used to obtain the
* {@link Future} of the consumer. You can use {@link Future#get()} to await
* the completion of the consumer, to cancel the consumer, etc. The
* {@link Future} will not terminate (other than by error) until the buffer
* has been {@link IBlockingBuffer#close() closed}. The {@link Future}
* evaluates to an {@link IndexAsyncWriteStats} object. Those statistics are
* also reported to the {@link ILoadBalancerService} via the
* {@link IBigdataFederation}.
* <p>
* Each buffer returned by this method is independent, and writes onto
* independent sinks which write through to the index partitions. This is
* necessary in order for the caller to retain control over the life cycle
* of their write operations. The {@link BlockingBuffer} is thread-safe so
* it may be the target for concurrent producers can be can utilized to
* create very high throughput designs. While the returned buffers are
* independent, the performance counters for all asynchronous write buffers
* for a given client and scale-out index are aggregated by a single
* {@link ScaleOutIndexCounters} instance.
*
* @param <T>
* The generic type of the procedure used to write on the index.
* @param <O>
* The generic type for unserialized value objects.
* @param <R>
* The type of the result from applying the index procedure to a
* single {@link Split} of data.
* @param <A>
* The type of the aggregated result.
*
* @param resultHandler
* Used to aggregate results.
* @param duplicateRemover
* Used to filter out duplicates in an application specified
* manner (optional).
* @param ctor
* Used to create instances of the procedure that will execute a
* write on an individual index partition (this implies that
* insert and remove operations as well as custom index write
* operations must use separate buffers).
*
* @return A buffer on which the producer may write their data.
*
* @see IndexMetadata#getAsynchronousIndexWriteConfiguration()
*
* @see AbstractFederation#getIndexCounters(String)
*
* @todo The async API is only defined at this time for scale-out index
* views. An asynchronous write API could be defined for local
* B+Trees. It would have to ensure locks using the
* {@link UnisolatedReadWriteIndex}. It would not use the same
* layering since writes could not be scattered. It could be written
* as a single blocking buffer which was drained by the CTOR for the
* operation. If we combine the two buffer capacity parameters into a
* single parameter, then this method signature could be used for both
* local and scale-out index views. This method could then be moved to
* an IAsynchronousIndexWriter interface.
*/
public <T extends IKeyArrayIndexProcedure, O, R, A> IRunnableBuffer<KVO<O>[]> newWriteBuffer(
final IResultHandler<R, A> resultHandler,
final IDuplicateRemover<O> duplicateRemover,
final AbstractKeyArrayIndexProcedureConstructor<T> ctor);
}