bundles/org.simantics.document.server/src/org/simantics/document/server/DocumentHistoryCollector.java

   1 package org.simantics.document.server;
   2
   3 import java.util.Collection;
   4 import java.util.Iterator;
   5 import java.util.Map;
   6 import java.util.Map.Entry;
   7
   8 import org.simantics.db.procedure.Listener;
   9 import org.simantics.utils.datastructures.Pair;
  10
  11 import gnu.trove.map.hash.THashMap;
  12
  13 public class DocumentHistoryCollector {
  14
  15         static Map<String, DocumentHistory> histories = new THashMap<String, DocumentHistory>();
  16
  17         private static DocumentHistory getHistory(String location, boolean create) {
  18
  19                 synchronized(histories) {
  20
  21                         DocumentHistory history =  histories.get(location);
  22                         if(history == null && create) {
  23                                 history = new DocumentHistory();
  24                                 pruneHistories();
  25                                 histories.put(location, history);
  26                         }
  27                         return history;
  28
  29                 }
  30
  31         }
  32
  33         private static void pruneHistories() {
  34                 synchronized (histories) {
  35                         // remove histories with no listeners
  36                         Iterator<Map.Entry<String, DocumentHistory>> iter = histories.entrySet().iterator();
  37                         while (iter.hasNext()) {
  38                         Entry<String, DocumentHistory> entry = iter.next();
  39                         DocumentHistory entryHistory = entry.getValue();
  40                         synchronized(entryHistory) {
  41                                 if (!entryHistory.hasListeners()) {
  42                                         iter.remove();
  43                                 }
  44                         }
  45                 }
  46                 }
  47         }
  48
  49         public static Pair<Integer, Collection<JSONObject>> readChanges(String location, int sequenceNumber) {
  50                 DocumentHistory history = getHistory(location, false);
  51                 if (history != null) {
  52                         return history.readChanges(sequenceNumber);
  53                 } else {
  54                         return null;
  55                 }
  56         }
  57
  58         public static Pair<Integer, Collection<JSONObject>> getContent(Listener<Integer> listener, String location, int sequenceNumber) {
  59                 DocumentHistory history = getHistory(location, true);
  60                 return history.getContent(listener, location, sequenceNumber);
  61         }
  62 }