content: /**
   * 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 backtype.storm.scheduler.multitenant;
  
  import java.util.Collection;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.Map;
  import java.util.Set;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import backtype.storm.scheduler.Cluster;
  import backtype.storm.scheduler.TopologyDetails;
  
  /**
   * All of the machines that currently have nothing assigned to them
   */
  public class FreePool extends NodePool {
      private static final Logger LOG = LoggerFactory.getLogger(FreePool.class);
      private Set<Node> _nodes = new HashSet<>();
      private int _totalSlots = 0;
  
      @Override
      public void init(Cluster cluster, Map<String, Node> nodeIdToNode) {
          super.init(cluster, nodeIdToNode);
          for (Node n : nodeIdToNode.values()) {
              if (n.isTotallyFree() && n.isAlive()) {
                  _nodes.add(n);
                  _totalSlots += n.totalSlotsFree();
              }
          }
          LOG.debug("Found {} nodes with {} slots", _nodes.size(), _totalSlots);
      }
  
      @Override
      public void addTopology(TopologyDetails td) {
          throw new IllegalArgumentException("The free pool cannot run any topologies");
      }
  
      @Override
      public boolean canAdd(TopologyDetails td) {
          // The free pool never has anything running
          return false;
      }
  
      @Override
      public Collection<Node> takeNodes(int nodesNeeded) {
          HashSet<Node> ret = new HashSet<>();
          Iterator<Node> it = _nodes.iterator();
          while (it.hasNext() && nodesNeeded > ret.size()) {
              Node n = it.next();
              ret.add(n);
              _totalSlots -= n.totalSlotsFree();
              it.remove();
          }
          return ret;
      }
  
      @Override
      public int nodesAvailable() {
          return _nodes.size();
      }
  
      @Override
      public int slotsAvailable() {
          return _totalSlots;
      }
  
      @Override
      public Collection<Node> takeNodesBySlots(int slotsNeeded) {
          HashSet<Node> ret = new HashSet<>();
          Iterator<Node> it = _nodes.iterator();
          while (it.hasNext() && slotsNeeded > 0) {
              Node n = it.next();
              ret.add(n);
              _totalSlots -= n.totalSlotsFree();
              slotsNeeded -= n.totalSlotsFree();
              it.remove();
          }
          return ret;
      }
  
      @Override
      public NodeAndSlotCounts getNodeAndSlotCountIfSlotsWereTaken(int slotsNeeded) {
          int slotsFound = 0;
          int nodesFound = 0;
          Iterator<Node> it = _nodes.iterator();
          while (it.hasNext() && slotsNeeded > 0) {
              Node n = it.next();
              nodesFound++;
              int totalSlots = n.totalSlots();
              slotsFound += totalSlots;
              slotsNeeded -= totalSlots;
          }
          return new NodeAndSlotCounts(nodesFound, slotsFound);
      }
  
      @Override
      public void scheduleAsNeeded(NodePool... lesserPools) {
          // No topologies running so NOOP
      }
  
      @Override
      public String toString() {
          return "FreePool of " + _nodes.size() + " nodes with " + _totalSlots + " slots";
      }
  }
  