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Elasticsearch subproject :server
/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch licenses this file to you 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 org.elasticsearch.http;
import org.elasticsearch.common.collect.Tuple;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;
import java.util.PriorityQueue;
public class HttpPipeliningAggregator {
private final int maxEventsHeld;
private final PriorityQueue> outboundHoldingQueue;
/*
* The current read and write sequence numbers. Read sequence numbers are attached to requests in the order they are read from the
* channel, and then transferred to responses. A response is not written to the channel context until its sequence number matches the
* current write sequence, implying that all preceding messages have been written.
*/
private int readSequence;
private int writeSequence;
public HttpPipeliningAggregator(int maxEventsHeld) {
this.maxEventsHeld = maxEventsHeld;
this.outboundHoldingQueue = new PriorityQueue<>(1, Comparator.comparing(Tuple::v1));
}
public HttpPipelinedRequest read(final Request request) {
return new HttpPipelinedRequest<>(readSequence++, request);
}
public List> write(final Response response, Listener listener) {
if (outboundHoldingQueue.size() < maxEventsHeld) {
ArrayList> readyResponses = new ArrayList<>();
outboundHoldingQueue.add(new Tuple<>(response, listener));
while (!outboundHoldingQueue.isEmpty()) {
/*
* Since the response with the lowest sequence number is the top of the priority queue, we know if its sequence
* number does not match the current write sequence number then we have not processed all preceding responses yet.
*/
final Tuple top = outboundHoldingQueue.peek();
if (top.v1().getSequence() != writeSequence) {
break;
}
outboundHoldingQueue.poll();
readyResponses.add(top);
writeSequence++;
}
return readyResponses;
} else {
int eventCount = outboundHoldingQueue.size() + 1;
throw new IllegalStateException("Too many pipelined events [" + eventCount + "]. Max events allowed ["
+ maxEventsHeld + "].");
}
}
public List> removeAllInflightResponses() {
ArrayList> responses = new ArrayList<>(outboundHoldingQueue);
outboundHoldingQueue.clear();
return responses;
}
}