it.tidalwave.role.ui.impl.PresentationModelComposite Maven / Gradle / Ivy

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/***********************************************************************************************************************
 *
 * blueBill Stats
 * Copyright (C) 2011-2011 by Tidalwave s.a.s. (http://www.tidalwave.it)
 *
 ***********************************************************************************************************************
 *
 * 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.
 *
 ***********************************************************************************************************************
 *
 * WWW: http://bluebill.tidalwave.it/mobile/
 * SCM: http://java.net/hg/bluebill-server~stats-src
 *
 **********************************************************************************************************************/
package it.tidalwave.role.ui.impl;

import lombok.Getter;
import javax.annotation.Nonnegative;
import javax.annotation.Nonnull;
import java.util.ArrayList;
import java.util.List;
import java.util.SortedMap;
import java.util.TreeMap;
import it.tidalwave.util.As;
import it.tidalwave.util.AsException;
import it.tidalwave.util.Finder;
import it.tidalwave.util.spi.FinderSupport;
import it.tidalwave.role.Composite;
import it.tidalwave.role.SimpleComposite;
import it.tidalwave.role.ui.PresentationModel;
import it.tidalwave.util.NotFoundException;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import static it.tidalwave.role.ui.Presentable.Presentable;

/***********************************************************************************************************************
 *
 * @author  Fabrizio Giudici
 * @version $Id$
 *
 **********************************************************************************************************************/
@RequiredArgsConstructor @Slf4j
/* package */ class PresentationModelComposite implements SimpleComposite 
  {
    private final SortedMap presentationModelMapByIndex = new TreeMap();
    
    @Nonnull
    private final Composite> delegateComposite;
    
    @Getter
    private boolean countComputed;
    
    private int count;

    /*******************************************************************************************************************
     *
     * {@inheritDoc}
     *
     ******************************************************************************************************************/
    @Override @Nonnull
    public Finder findChildren() 
      {
        return new FinderSupport>() 
          {
            @Override
            public int count() 
              {
                return Math.min(maxResults, computeCount() - firstResult);
              }

            @Override @Nonnull
            protected List computeNeededResults()
              {
                final List result = new ArrayList();
                int i = 0;

                try
                  {
                    for (; i < count(); i++)
                      {
                        result.add(NotFoundException.throwWhenNull(presentationModelMapByIndex.get(firstResult + i), ""));
                      }
                  }
                catch (NotFoundException e) // some objects not in the cache
                  {
                    final List objects = delegateComposite.findChildren().from(firstResult).max(maxResults).results();

                    for (; i < count(); i++)
                      {
                        result.add(getPresentationModel(firstResult + i, objects.get(i)));
                      }
                  }
                
                return result;
              }
          };
      }     
    
    /*******************************************************************************************************************
     *
     *
     ******************************************************************************************************************/
    @Nonnull
    private synchronized  PresentationModel getPresentationModel (final @Nonnegative int index, 
                                                                  final @Nonnull Object object)
      {
        PresentationModel presentationModel = presentationModelMapByIndex.get(index);
        
        if (presentationModel == null)
          {
            presentationModel = createPresentationModelFor(object);
            presentationModelMapByIndex.put(index, presentationModel);
          }
        
        return presentationModel;
      } 
    
    /*******************************************************************************************************************
     *
     *
     ******************************************************************************************************************/
    private int computeCount()
      {
        if (!countComputed)
          {
            log.debug(">>>> computing children count...");
            count = delegateComposite.findChildren().count();
            countComputed = true;
          }
        
        return count;
      }
    
    /*******************************************************************************************************************
     *
     *
     ******************************************************************************************************************/
    @Nonnull
    private PresentationModel createPresentationModelFor (final @Nonnull Object object)
      {
        try
          {
            if (!(object instanceof As))
              {
                throw new AsException(As.class);
              }

            return ((As)object).as(Presentable).createPresentationModel();
          }
        catch (AsException e)
          {
            return new AsLookupPresentationModel(object); // FIXME: use PresentationModelFactory
          }
      }
  }