| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF 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.apache.solr.cloud; |
| |
| import java.util.List; |
| import org.apache.lucene.util.PriorityQueue; |
| import org.apache.solr.common.cloud.SolrZkClient; |
| import org.apache.zookeeper.KeeperException; |
| import org.apache.zookeeper.data.Stat; |
| |
| /** |
| * A size limited distributed map maintained in zk. |
| * Oldest znodes (as per modification time) are evicted as newer ones come in. |
| * |
| * When the map hits the specified maximum size, the oldest <code>maxSize / 10</code> items |
| * are evicted on the next {@link #put(String, byte[])} invocation. |
| */ |
| public class SizeLimitedDistributedMap extends DistributedMap { |
| |
| private final int maxSize; |
| |
| /** |
| * This observer will be called when this map overflows, and deletes the excess of elements |
| */ |
| private final OnOverflowObserver onOverflowObserver; |
| |
| public SizeLimitedDistributedMap(SolrZkClient zookeeper, String dir, int maxSize) { |
| this(zookeeper, dir, maxSize, null); |
| } |
| |
| public SizeLimitedDistributedMap(SolrZkClient zookeeper, String dir, int maxSize, OnOverflowObserver onOverflowObserver) { |
| super(zookeeper, dir); |
| this.maxSize = maxSize; |
| this.onOverflowObserver = onOverflowObserver; |
| } |
| |
| @Override |
| public void put(String trackingId, byte[] data) throws KeeperException, InterruptedException { |
| if (this.size() >= maxSize) { |
| // Bring down the size |
| List<String> children = zookeeper.getChildren(dir, null, true); |
| |
| int cleanupSize = maxSize / 10; |
| |
| final PriorityQueue<Long> priorityQueue = new PriorityQueue<Long>(cleanupSize) { |
| @Override |
| protected boolean lessThan(Long a, Long b) { |
| return (a > b); |
| } |
| }; |
| |
| for (String child : children) { |
| Stat stat = zookeeper.exists(dir + "/" + child, null, true); |
| priorityQueue.insertWithOverflow(stat.getMzxid()); |
| } |
| |
| long topElementMzxId = priorityQueue.top(); |
| |
| for (String child : children) { |
| Stat stat = zookeeper.exists(dir + "/" + child, null, true); |
| if (stat.getMzxid() <= topElementMzxId) { |
| zookeeper.delete(dir + "/" + child, -1, true); |
| if (onOverflowObserver != null) onOverflowObserver.onChildDelete(child.substring(PREFIX.length())); |
| } |
| } |
| } |
| |
| super.put(trackingId, data); |
| } |
| |
| interface OnOverflowObserver { |
| void onChildDelete(String child) throws KeeperException, InterruptedException; |
| } |
| } |