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Composable asynchronous/reactive streams with powerful data processing capabilities.
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/*
 * Copyright (C) 2015 SoftIndex LLC.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package io.datakernel.stream.processor;

import io.datakernel.eventloop.Eventloop;
import io.datakernel.stream.AbstractStreamProducer;
import io.datakernel.stream.AbstractStreamTransformer_1_N;
import io.datakernel.stream.StreamDataReceiver;
import io.datakernel.stream.StreamProducer;

import static java.lang.System.arraycopy;

@SuppressWarnings("unchecked")
public class StreamSplitter extends AbstractStreamTransformer_1_N implements StreamDataReceiver, StreamSplitterMBean {
	protected StreamDataReceiver[] dataReceivers = new StreamDataReceiver[]{};

	private int jmxItems;

	public StreamSplitter(Eventloop eventloop) {
		super(eventloop);
	}

	public class InternalProducer extends AbstractStreamProducer {
		public InternalProducer(Eventloop eventloop) {
			super(eventloop);
		}

		@Override
		public void bindDataReceiver() {
			super.bindDataReceiver();
			dataReceivers[outputs.indexOf(this)] = downstreamDataReceiver;
			onDataReceiverChanged(outputs.indexOf(this));
		}

		@Override
		protected void onSuspended() {
			suspendUpstream();
		}

		@Override
		protected void onResumed() {
			if (allOutputsResumed()) {
				resumeUpstream();
			}
		}

		@Override
		protected void onClosed() {
			closeUpstream();
		}

		@Override
		protected void onClosedWithError(Exception e) {
			onError(e);
			downstreamConsumer.onError(e);
		}
	}

	public StreamProducer newOutput() {
		InternalProducer newOutput = new InternalProducer(eventloop);
		addOutput(newOutput);

		StreamDataReceiver[] newDataReceivers = new StreamDataReceiver[dataReceivers.length + 1];
		arraycopy(dataReceivers, 0, newDataReceivers, 0, dataReceivers.length);
		dataReceivers = newDataReceivers;

		return newOutput;
	}

	@Override
	public void onEndOfStream() {
		sendEndOfStreamToDownstreams();
	}

	@Override
	public StreamDataReceiver getDataReceiver() {
		return this;
	}

	@SuppressWarnings("AssertWithSideEffects")
	@Override
	public void onData(T item) {
		assert jmxItems != ++jmxItems;
		for (StreamDataReceiver streamCallback : dataReceivers) {
			streamCallback.onData(item);
		}
	}

	@Override
	public int getItems() {
		return jmxItems;
	}

	@SuppressWarnings("AssertWithSideEffects")
	@Override
	public String toString() {
		String items = "?";
		assert (items = "" + jmxItems) != null;
		return '{' + super.toString() + " items:" + items + '}';
	}
}