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   *  to you under the Apache License, Version 2.0 (the
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  package org.apache.cayenne.jcache;
  
  import java.util.List;
  import javax.cache.processor.EntryProcessor;
  import javax.cache.processor.EntryProcessorException;
  import javax.cache.processor.MutableEntry;
  
  import org.apache.cayenne.CayenneRuntimeException;
  import org.apache.cayenne.cache.QueryCacheEntryFactory;
  
  /**
   * @since 4.0
   */
  public class JCacheEntryLoader implements EntryProcessor<String, List, List> {
  
      private QueryCacheEntryFactory entryFactory;
  
      public JCacheEntryLoader(QueryCacheEntryFactory entryFactory) {
          this.entryFactory = entryFactory;
      }
  
      @Override
      public List process(MutableEntry<String, List> entry, Object... arguments) throws EntryProcessorException {
          if (!entry.exists()) {
              List result = (List)entryFactory.createObject();
              // sanity checking value
              if (result == null) {
                  throw new CayenneRuntimeException("Null object created: %s", entry.getKey());
              }
              entry.setValue(result);
          }
  
          return entry.getValue();
      }
  }
  