stream.io.multi.MergeAllMultiDataStream Maven / Gradle / Ivy
/*
* streams library
*
* Copyright (C) 2011-2012 by Christian Bockermann, Hendrik Blom
*
* streams is a library, API and runtime environment for processing high
* volume data streams. It is composed of three submodules "stream-api",
* "stream-core" and "stream-runtime".
*
* The streams library (and its submodules) is free software: you can
* redistribute it and/or modify it under the terms of the
* GNU Affero General Public License as published by the Free Software
* Foundation, either version 3 of the License, or (at your option) any
* later version.
*
* The stream.ai library (and its submodules) 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see http://www.gnu.org/licenses/.
*/
package stream.io.multi;
import java.util.Map;
import stream.data.Data;
import stream.data.DataFactory;
import stream.io.DataStream;
/**
* *
*
* A simple multi stream implementation, that merges the items of the
* substreams.
*
*
* @author Hendrik Blom
*
*/
public class MergeAllMultiDataStream extends AbstractMultiDataStream {
/**
* @see stream.io.multi.AbstractMultiDataStream#readItem(stream.data.Data)
*/
@Override
protected Data readNext(Data item, Map streams)
throws Exception {
if (item == null)
item = DataFactory.create();
boolean stop = true;
for (String id : additionOrder) {
DataStream s = streams.get(id);
Data d = s.readNext(item);
if (d != null) {
item.putAll(d);
stop = false;
}
}
if (stop)
return null;
return item;
}
}