content: /*
   * Copyright 1999-2018 Alibaba Group Holding Ltd.
   *
   * 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 com.alibaba.csp.sentinel.node;
  
  import java.util.HashMap;
  import java.util.Map;
  import java.util.concurrent.locks.ReentrantLock;
  
  import com.alibaba.csp.sentinel.ResourceTypeConstants;
  import com.alibaba.csp.sentinel.context.ContextUtil;
  import com.alibaba.csp.sentinel.slots.block.BlockException;
  import com.alibaba.csp.sentinel.util.AssertUtil;
  
  /**
   * <p>
   * This class stores summary runtime statistics of the resource, including rt, thread count, qps
   * and so on. Same resource shares the same {@link ClusterNode} globally, no matter in which
   * {@link com.alibaba.csp.sentinel.context.Context}.
   * </p>
   * <p>
   * To distinguish invocation from different origin (declared in
   * {@link ContextUtil#enter(String name, String origin)}),
   * one {@link ClusterNode} holds an {@link #originCountMap}, this map holds {@link StatisticNode}
   * of different origin. Use {@link #getOrCreateOriginNode(String)} to get {@link Node} of the specific
   * origin.<br/>
   * Note that 'origin' usually is Service Consumer's app name.
   * </p>
   *
   * @author qinan.qn
   * @author jialiang.linjl
   */
  public class ClusterNode extends StatisticNode {
  
      private final String name;
      private final int resourceType;
  
      public ClusterNode(String name) {
          this(name, ResourceTypeConstants.COMMON);
      }
  
      public ClusterNode(String name, int resourceType) {
          AssertUtil.notEmpty(name, "name cannot be empty");
          this.name = name;
          this.resourceType = resourceType;
      }
  
      /**
       * <p>The origin map holds the pair: (origin, originNode) for one specific resource.</p>
       * <p>
       * The longer the application runs, the more stable this mapping will become.
       * So we didn't use concurrent map here, but a lock, as this lock only happens
       * at the very beginning while concurrent map will hold the lock all the time.
       * </p>
       */
      private Map<String, StatisticNode> originCountMap = new HashMap<>();
  
      private final ReentrantLock lock = new ReentrantLock();
  
      /**
       * Get resource name of the resource node.
       *
       * @return resource name
       * @since 1.7.0
       */
      public String getName() {
          return name;
      }
  
      /**
       * Get classification (type) of the resource.
       *
       * @return resource type
       * @since 1.7.0
       */
      public int getResourceType() {
          return resourceType;
      }
  
      /**
       * <p>Get {@link Node} of the specific origin. Usually the origin is the Service Consumer's app name.</p>
       * <p>If the origin node for given origin is absent, then a new {@link StatisticNode}
       * for the origin will be created and returned.</p>
       *
       * @param origin The caller's name, which is designated in the {@code parameter} parameter
       *               {@link ContextUtil#enter(String name, String origin)}.
       * @return the {@link Node} of the specific origin
       */
      public Node getOrCreateOriginNode(String origin) {
          StatisticNode statisticNode = originCountMap.get(origin);
          if (statisticNode == null) {
              lock.lock();
              try {
                  statisticNode = originCountMap.get(origin);
                  if (statisticNode == null) {
                      // The node is absent, create a new node for the origin.
                      statisticNode = new StatisticNode();
                      HashMap<String, StatisticNode> newMap = new HashMap<>(originCountMap.size() + 1);
                      newMap.putAll(originCountMap);
                      newMap.put(origin, statisticNode);
                      originCountMap = newMap;
                  }
              } finally {
                  lock.unlock();
              }
          }
          return statisticNode;
      }
  
      public Map<String, StatisticNode> getOriginCountMap() {
          return originCountMap;
      }
  
  }
  