content: /*
   * Copyright 2010-2025 Hyland Software, Inc. and its affiliates.
   *
   * 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 org.activiti.engine.impl.persistence.deploy;
  
  import static java.util.Collections.synchronizedMap;
  
  import com.fasterxml.jackson.databind.ObjectMapper;
  import com.fasterxml.jackson.databind.node.ObjectNode;
  import java.util.HashMap;
  import java.util.LinkedHashMap;
  import java.util.Map;
  import org.activiti.engine.ActivitiException;
  import org.activiti.engine.impl.context.Context;
  import org.activiti.engine.impl.interceptor.Command;
  import org.activiti.engine.impl.interceptor.CommandContext;
  import org.activiti.engine.impl.interceptor.CommandExecutor;
  import org.activiti.engine.impl.persistence.entity.ProcessDefinitionInfoEntity;
  import org.activiti.engine.impl.persistence.entity.ProcessDefinitionInfoEntityManager;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Default cache: keep everything in memory, unless a limit is set.
   *
  
   */
  public class ProcessDefinitionInfoCache {
  
      private static final Logger logger = LoggerFactory.getLogger(ProcessDefinitionInfoCache.class);
  
      protected Map<String, ProcessDefinitionInfoCacheObject> cache;
      protected CommandExecutor commandExecutor;
  
      /** Cache with no limit */
      public ProcessDefinitionInfoCache(CommandExecutor commandExecutor) {
          this.commandExecutor = commandExecutor;
          this.cache = synchronizedMap(new HashMap<String, ProcessDefinitionInfoCacheObject>());
      }
  
      /** Cache which has a hard limit: no more elements will be cached than the limit. */
      public ProcessDefinitionInfoCache(CommandExecutor commandExecutor, final int limit) {
          this.commandExecutor = commandExecutor;
          this.cache = synchronizedMap(
              new LinkedHashMap<String, ProcessDefinitionInfoCacheObject>(limit + 1, 0.75f, true) {
                  // +1 is needed, because the entry is inserted first, before it is removed
                  // 0.75 is the default (see javadocs)
                  // true will keep the 'access-order', which is needed to have a real LRU cache
                  private static final long serialVersionUID = 1L;
  
                  protected boolean removeEldestEntry(Map.Entry<String, ProcessDefinitionInfoCacheObject> eldest) {
                      boolean removeEldest = size() > limit;
                      if (removeEldest) {
                          logger.trace("Cache limit is reached, {} will be evicted", eldest.getKey());
                      }
                      return removeEldest;
                  }
              }
          );
      }
  
      public ProcessDefinitionInfoCacheObject get(final String processDefinitionId) {
          ProcessDefinitionInfoCacheObject infoCacheObject = null;
          Command<ProcessDefinitionInfoCacheObject> cacheCommand = new Command<ProcessDefinitionInfoCacheObject>() {
              @Override
              public ProcessDefinitionInfoCacheObject execute(CommandContext commandContext) {
                  return retrieveProcessDefinitionInfoCacheObject(processDefinitionId, commandContext);
              }
          };
  
          if (Context.getCommandContext() != null) {
              infoCacheObject = retrieveProcessDefinitionInfoCacheObject(
                  processDefinitionId,
                  Context.getCommandContext()
              );
          } else {
              infoCacheObject = commandExecutor.execute(cacheCommand);
          }
  
          return infoCacheObject;
      }
  
      public void add(String id, ProcessDefinitionInfoCacheObject obj) {
          cache.put(id, obj);
      }
  
      public void remove(String id) {
          cache.remove(id);
      }
  
      public void clear() {
          cache.clear();
      }
  
      // For testing purposes only
      public int size() {
          return cache.size();
      }
  
      protected ProcessDefinitionInfoCacheObject retrieveProcessDefinitionInfoCacheObject(
          String processDefinitionId,
          CommandContext commandContext
      ) {
          ProcessDefinitionInfoEntityManager infoEntityManager = commandContext.getProcessDefinitionInfoEntityManager();
          ObjectMapper objectMapper = commandContext.getProcessEngineConfiguration().getObjectMapper();
  
          ProcessDefinitionInfoCacheObject cacheObject = null;
          if (cache.containsKey(processDefinitionId)) {
              cacheObject = cache.get(processDefinitionId);
          } else {
              cacheObject = new ProcessDefinitionInfoCacheObject();
              cacheObject.setRevision(0);
              cacheObject.setInfoNode(objectMapper.createObjectNode());
          }
  
          ProcessDefinitionInfoEntity infoEntity = infoEntityManager.findProcessDefinitionInfoByProcessDefinitionId(
              processDefinitionId
          );
          if (infoEntity != null && infoEntity.getRevision() != cacheObject.getRevision()) {
              cacheObject.setRevision(infoEntity.getRevision());
              if (infoEntity.getInfoJsonId() != null) {
                  byte[] infoBytes = infoEntityManager.findInfoJsonById(infoEntity.getInfoJsonId());
                  try {
                      ObjectNode infoNode = (ObjectNode) objectMapper.readTree(infoBytes);
                      cacheObject.setInfoNode(infoNode);
                  } catch (Exception e) {
                      throw new ActivitiException(
                          "Error reading json info node for process definition " + processDefinitionId,
                          e
                      );
                  }
              }
          } else if (infoEntity == null) {
              cacheObject.setRevision(0);
              cacheObject.setInfoNode(objectMapper.createObjectNode());
          }
  
          return cacheObject;
      }
  }
  