chris@3: /*
chris@3:  *   SONEWS News Server
chris@3:  *   see AUTHORS for the list of contributors
chris@3:  *
chris@3:  *   This program is free software: you can redistribute it and/or modify
chris@3:  *   it under the terms of the GNU General Public License as published by
chris@3:  *   the Free Software Foundation, either version 3 of the License, or
chris@3:  *   (at your option) any later version.
chris@3:  *
chris@3:  *   This program is distributed in the hope that it will be useful,
chris@3:  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
chris@3:  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
chris@3:  *   GNU General Public License for more details.
chris@3:  *
chris@3:  *   You should have received a copy of the GNU General Public License
chris@3:  *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
chris@3:  */
chris@3: 
chris@3: package org.sonews.storage;
chris@3: 
chris@3: import java.util.ArrayList;
chris@3: import java.util.Collections;
chris@3: import java.util.List;
chris@3: import org.sonews.util.Pair;
chris@3: 
chris@3: /**
chris@3:  * An aggregated group is a group consisting of several "real" group.
chris@3:  * @author Christian Lins
chris@3:  * @since sonews/1.0
chris@3:  */
chris@3: class AggregatedGroup extends Channel
chris@3: {
chris@3: 
chris@3:   static class GroupElement
chris@3:   {
chris@3:     private Group group;
chris@3:     private long  offsetStart, offsetEnd;
chris@3:     
chris@3:     public GroupElement(Group group, long offsetStart, long offsetEnd)
chris@3:     {
chris@3:       this.group       = group;
chris@3:       this.offsetEnd   = offsetEnd;
chris@3:       this.offsetStart = offsetStart;
chris@3:     }
chris@3:   }
chris@3: 
chris@3:   public static List<Channel> getAll()
chris@3:   {
chris@3:     List<Channel> all = new ArrayList<Channel>();
chris@3:     all.add(getByName("agg.test"));
chris@3:     return all;
chris@3:   }
chris@3: 
chris@3:   public static AggregatedGroup getByName(String name)
chris@3:   {
chris@3:     if("agg.test".equals(name))
chris@3:     {
chris@3:       AggregatedGroup agroup = new AggregatedGroup(name);
chris@3:       agroup.addGroup(Group.getByName("agg.test0"), 0, 1000);
chris@3:       agroup.addGroup(Group.getByName("agg.test1"), 2000, 4000);
chris@3:       return agroup;
chris@3:     }
chris@3:     else
chris@3:       return null;
chris@3:   }
chris@3: 
chris@3:   private GroupElement[] groups = new GroupElement[2];
chris@3:   private String         name;
chris@3: 
chris@3:   public AggregatedGroup(String name)
chris@3:   {
chris@3:     this.name = name;
chris@3:   }
chris@3: 
chris@3:   private long aggIdxToIdx(long aggIdx)
chris@3:     throws StorageBackendException
chris@3:   {
chris@3:     assert groups != null && groups.length == 2;
chris@3:     assert groups[0] != null;
chris@3:     assert groups[1] != null;
chris@3: 
chris@3:     // Search in indices of group one
chris@3:     List<Long> idxs0 = groups[0].group.getArticleNumbers();
chris@3:     Collections.sort(idxs0);
chris@3:     for(long idx : idxs0)
chris@3:     {
chris@3:       if(idx == aggIdx)
chris@3:       {
chris@3:         return idx;
chris@3:       }
chris@3:     }
chris@3: 
chris@3:     // Given aggIdx must be an index of group two
chris@3:     List<Long> idxs1 = groups[1].group.getArticleNumbers();
chris@3:     return 0;
chris@3:   }
chris@3:   
chris@3:   private long idxToAggIdx(long idx)
chris@3:   {
chris@3:     return 0;
chris@3:   }
chris@3: 
chris@3:   /**
chris@3:    * Adds the given group to this aggregated set.
chris@3:    * @param group
chris@3:    * @param offsetStart Lower limit for the article ids range
chris@3:    */
chris@3:   public void addGroup(Group group, long offsetStart, long offsetEnd)
chris@3:   {
chris@3:     this.groups[groups[0] == null ? 0 : 1]
chris@3:       = new GroupElement(group, offsetStart, offsetEnd);
chris@3:   }
chris@3: 
chris@3:   @Override
chris@3:   public Article getArticle(long idx)
chris@3:     throws StorageBackendException
chris@3:   {
chris@3:     Article article = null;
chris@3: 
chris@3:     for(GroupElement groupEl : groups)
chris@3:     {
chris@3:       if(groupEl.offsetStart <= idx && groupEl.offsetEnd >= idx)
chris@3:       {
chris@3:         article = groupEl.group.getArticle(idx - groupEl.offsetStart);
chris@3:         break;
chris@3:       }
chris@3:     }
chris@3: 
chris@3:     return article;
chris@3:   }
chris@3: 
chris@3:   @Override
chris@3:   public List<Pair<Long, ArticleHead>> getArticleHeads(
chris@3:     final long first, final long last)
chris@3:     throws StorageBackendException
chris@3:   {
chris@3:     List<Pair<Long, ArticleHead>> heads = new ArrayList<Pair<Long, ArticleHead>>();
chris@3:     
chris@3:     for(GroupElement groupEl : groups)
chris@3:     {
chris@3:       List<Pair<Long, ArticleHead>> partHeads = new ArrayList<Pair<Long, ArticleHead>>();
chris@3:       if(groupEl.offsetStart <= first && groupEl.offsetEnd >= first)
chris@3:       {
chris@3:         long end = Math.min(groupEl.offsetEnd, last);
chris@3:         partHeads = groupEl.group.getArticleHeads
chris@3:           (first - groupEl.offsetStart, end - groupEl.offsetStart);
chris@3:       }
chris@3:       else if(groupEl.offsetStart <= last && groupEl.offsetEnd >= last)
chris@3:       {
chris@3:         long start = Math.max(groupEl.offsetStart, first);
chris@3:         partHeads = groupEl.group.getArticleHeads
chris@3:           (start - groupEl.offsetStart, last - groupEl.offsetStart);
chris@3:       }
chris@3: 
chris@3:       for(Pair<Long, ArticleHead> partHead : partHeads)
chris@3:       {
chris@3:         heads.add(new Pair<Long, ArticleHead>(
chris@3:           partHead.getA() + groupEl.offsetStart, partHead.getB()));
chris@3:       }
chris@3:     }
chris@3: 
chris@3:     return heads;
chris@3:   }
chris@3: 
chris@3:   @Override
chris@3:   public List<Long> getArticleNumbers()
chris@3:     throws StorageBackendException
chris@3:   {
chris@3:     List<Long> articleNumbers = new ArrayList<Long>();
chris@3:     
chris@3:     for(GroupElement groupEl : groups)
chris@3:     {
chris@3:       List<Long> partNums = groupEl.group.getArticleNumbers();
chris@3:       for(Long partNum : partNums)
chris@3:       {
chris@3:         articleNumbers.add(partNum + groupEl.offsetStart);
chris@3:       }
chris@3:     }
chris@3: 
chris@3:     return articleNumbers;
chris@3:   }
chris@3: 
chris@3:   @Override
chris@3:   public long getIndexOf(Article art)
chris@3:     throws StorageBackendException
chris@3:   {
chris@3:     for(GroupElement groupEl : groups)
chris@3:     {
chris@3:       long idx = groupEl.group.getIndexOf(art);
chris@3:       if(idx > 0)
chris@3:       {
chris@3:         return idx;
chris@3:       }
chris@3:     }
chris@3:     return -1;
chris@3:   }
chris@3: 
chris@3:   public long getInternalID()
chris@3:   {
chris@3:     return -1;
chris@3:   }
chris@3: 
chris@3:   @Override
chris@3:   public String getName()
chris@3:   {
chris@3:     return this.name;
chris@3:   }
chris@3: 
chris@3:   @Override
chris@3:   public long getFirstArticleNumber()
chris@3:     throws StorageBackendException
chris@3:   {
chris@3:     long first = Long.MAX_VALUE;
chris@3: 
chris@3:     for(GroupElement groupEl : groups)
chris@3:     {
chris@3:       first = Math.min(first, groupEl.group.getFirstArticleNumber() + groupEl.offsetStart);
chris@3:     }
chris@3: 
chris@3:     return first;
chris@3:   }
chris@3: 
chris@3:   @Override
chris@3:   public long getLastArticleNumber()
chris@3:     throws StorageBackendException
chris@3:   {
chris@3:     long last = 1;
chris@3: 
chris@3:     for(GroupElement groupEl : groups)
chris@3:     {
chris@3:       last = Math.max(last, groupEl.group.getLastArticleNumber() + groupEl.offsetStart);
chris@3:     }
chris@3: 
chris@3:     return last + getPostingsCount(); // This is a hack
chris@3:   }
chris@3:   
chris@3:   public long getPostingsCount()
chris@3:     throws StorageBackendException
chris@3:   {
chris@3:     long postings = 0;
chris@3: 
chris@3:     for(GroupElement groupEl : groups)
chris@3:     {
chris@3:       postings += groupEl.group.getPostingsCount();
chris@3:     }
chris@3: 
chris@3:     return postings;
chris@3:   }
chris@3: 
chris@3:   public boolean isDeleted()
chris@3:   {
chris@3:     return false;
chris@3:   }
chris@3: 
chris@3:   public boolean isWriteable()
chris@3:   {
chris@3:     return false;
chris@3:   }
chris@3: 
chris@3: }