/src/edu/ucsb/nceas/metacat/DBQuery.java - Diff - Metacat - Ecoinformatics Redmine

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Revision 3342

Added by Jing Tao over 16 years ago

Add a cache mechanism for public user.

         Vector docidOverride = new Vector();
         // a hash table serves as query reuslt cache. Key of hashtable
         // is a query string and value is ResultDocumentSet Object
         // is a query string and value is result xml string
         private static Hashtable queryResultCache = new Hashtable();
         // Capacity of the query result cache
-...
         HttpSession sess = (HttpSession)sessionHash.get(sessionid);
         resultset.append("<?xml version=\"1.0\"?>\n");
         resultset.append("<resultset>\n");
         resultset.append("  <pagestart>" + pagestart + "</pagestart>\n");
-...
             //print out the search result
             // search the doc list
             resultset = findResultDoclist(qspec, resultset, out, user, groups,
             StringBuffer resultContent = findResultDoclist(qspec, out, user, groups,
                                           dbconn, useXMLIndex, pagesize, pagestart,
                                           sessionid);
             resultset.append(resultContent);
           } //try
           catch (IOException ioe)
+          {
-...
          * Find the doc list which match the query
          */
         private StringBuffer findResultDoclist(QuerySpecification qspec,
                                           StringBuffer resultsetBuffer,
                                           PrintWriter out,
                                           String user, String[]groups,
                                           DBConnection dbconn, boolean useXMLIndex,
                                           int pagesize, int pagestart, String sessionid)
                                           throws Exception
+        {
           StringBuffer resultsetBuffer = new StringBuffer();
           String query = null;
           int count = 0;
           int index = 0;
-...
+          }
           logMetacat.warn("============ final selection query: " + query);
           // we only get cache for public
           if (user != null && user.equalsIgnoreCase("public")
          		 && pagesize == 0 && MetaCatUtil.getOption("query_cache_on").equals("true"))
+          {
        	      String cachedResult = getResultXMLFromCache(query);
        	      //System.out.println("==========the string from cache is "+cachedResult);
        	      if (cachedResult != null)
+       	      {
        	    	 if (out != null)
+       	         {
        	             out.println(cachedResult);
+       	         }
        	    	 resultsetBuffer.append(cachedResult);
        	    	 return resultsetBuffer;
+       	      }
+          }
           startTime = System.currentTimeMillis() / 1000;
           pstmt = dbconn.prepareStatement(query);
           rs = pstmt.executeQuery();
-...
           if(pagesize == 0)
           { //this makes sure we get all results if there is no paging
             pagesize = 99999;
             pagestart = 99999;
             pagesize = 9999999;
             pagestart = 9999999;
+          }
           int currentIndex = 0;
-...
+           {
              ResultDocumentSet pagedResultsHash = new ResultDocumentSet();
              //get the last page of information then break
              if(pagesize != 99999)
              if(pagesize != 9999999)
+             {
                for(int i=pagesize*pagestart; i<docListResult.size(); i++)
+               {
-...
          //if docListResult is not empty, it need to be sent.
          if (docListResult.size() != 0)
+         {
            handleSubsetResult(qspec,resultsetBuffer, out, docListResult,
                                   user, groups,dbconn, useXMLIndex);
+         }
-...
+         {
              out.println("\n<lastpage>" + lastpage + "</lastpage>\n");
+         }
          // now we only cached none-paged query and user is public
          if (user != null && user.equalsIgnoreCase("public")
         		 && pagesize == 9999999 && MetaCatUtil.getOption("query_cache_on").equals("true"))
+         {
            //System.out.println("the string stored into cache is "+ resultsetBuffer.toString());
       	   storeQueryResultIntoCache(query, resultsetBuffer.toString());
+         }
          return resultsetBuffer;
         }//findReturnDoclist
-...
+       }
        /*
         * Method to store query string and DocumentResultSet into query result
         * Method to store query string and result xml string into query result
         * cache. If the size alreay reache the limitation, the cache will be
         * cleared first, then store them.
         */
        private void storeQueryResultIntoCache(String query, ResultDocumentSet resultSet)
        private void storeQueryResultIntoCache(String query, String resultXML)
+       {
     	   synchronized (queryResultCache)
+    	   {
-...
+    		   {
     			   queryResultCache.clear();
+    		   }
     		   queryResultCache.put(query, resultSet);
     		   queryResultCache.put(query, resultXML);
+    	   }
+       }
        /*
         * Method to get DocumentResultSet from query result cache.
         * Note: the returned ResultDoucmentSet can be null.
         * Method to get result xml string from query result cache.
         * Note: the returned string can be null.
         */
        private ResultDocumentSet getResultDocumentSetFromCache(String query)
        private String getResultXMLFromCache(String query)
+       {
     	   ResultDocumentSet resultSet = null;
     	   String resultSet = null;
     	   synchronized (queryResultCache)
+    	   {
               try
+              {
     		     resultSet = (ResultDocumentSet)queryResultCache.get(query);
     		     resultSet = (String)queryResultCache.get(query);
+              }
               catch (Exception e)

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Revision 3342

Added by Jing Tao over 16 years ago