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 org.apache.causeway.core.runtimeservices.scratchpad;
  
  import java.util.Map;
  
  import jakarta.annotation.Priority;
  import jakarta.inject.Named;
  
  import org.springframework.beans.factory.annotation.Qualifier;
  import org.springframework.stereotype.Service;
  
  import org.apache.causeway.applib.annotation.InteractionScope;
  import org.apache.causeway.applib.annotation.PriorityPrecedence;
  import org.apache.causeway.applib.services.scratchpad.Scratchpad;
  import org.apache.causeway.commons.internal.collections._Maps;
  import org.apache.causeway.core.runtimeservices.CausewayModuleCoreRuntimeServices;
  
  /**
   * Default implementation of {@link Scratchpad}, which simply stores data in-memory.
   *
   * <p>
   *     This service is {@link InteractionScope}d, so no memory leak ought to be possible.
   * </p>
   *
   * @since 2.0 {@index}
   */
  @Service
  @Named(CausewayModuleCoreRuntimeServices.NAMESPACE + ".Scratchpad")
  @Priority(PriorityPrecedence.EARLY)
  @Qualifier("Default")
  @InteractionScope
  //@Log4j2
  public class ScratchpadDefault implements Scratchpad {
  
      /**
       * Provides a mechanism for each object being acted upon to pass
       * data to the next object.
       */
      private final Map<Object, Object> userData = _Maps.newHashMap();
  
      /**
       * Obtain user-data, as set by a previous object being acted upon.
       */
      @Override
      public Object get(Object key) {
          return userData.get(key);
      }
  
      /**
       * Set user-data, for the use of a subsequent object being acted upon.
       */
      @Override
      public void put(Object key, Object value) {
          userData.put(key, value);
      }
  
      /**
       * Clear any user data.
       */
      @Override
      public void destroy() throws Exception {
          userData.clear();
      }
  }
  