code: // Licensed to the Software Freedom Conservancy (SFC) under one
  // or more contributor license agreements.  See the NOTICE file
  // distributed with this work for additional information
  // regarding copyright ownership.  The SFC 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.openqa.selenium.grid.data;
  
  import static java.util.Collections.unmodifiableSet;
  
  import java.lang.reflect.Type;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.HashSet;
  import java.util.Map;
  import java.util.Set;
  import org.openqa.selenium.internal.Require;
  import org.openqa.selenium.json.JsonInput;
  import org.openqa.selenium.json.TypeToken;
  
  public class DistributorStatus {
  
    private static final Type NODE_STATUSES_TYPE = new TypeToken<Set<NodeStatus>>() {}.getType();
  
    private final Set<NodeStatus> allNodes;
  
    public DistributorStatus(Collection<NodeStatus> allNodes) {
      this.allNodes = unmodifiableSet(new HashSet<>(Require.nonNull("nodes", allNodes)));
    }
  
    public boolean hasCapacity() {
      return getNodes().stream()
          .map(node -> node.getAvailability().equals(Availability.UP) && node.hasCapacity())
          .reduce(Boolean::logicalOr)
          .orElse(false);
    }
  
    public Set<NodeStatus> getNodes() {
      return allNodes;
    }
  
    private Map<String, Object> toJson() {
      return Collections.singletonMap("nodes", getNodes());
    }
  
    private static DistributorStatus fromJson(JsonInput input) {
      Set<NodeStatus> nodes = null;
  
      input.beginObject();
      while (input.hasNext()) {
        switch (input.nextName()) {
          case "nodes":
            nodes = input.read(NODE_STATUSES_TYPE);
            break;
  
          default:
            input.skipValue();
        }
      }
      input.endObject();
  
      return new DistributorStatus(nodes);
    }
  }
  