import java.util.*;
  
  
  String event = arg("workerEvent");
  if ( event == "done" || event =="alreadyRunning" || event == "longRunningTask")
    return;
  
  final WindowContext context = argObj("windowContext");
  Worker worker = argObj("worker");
  final HashObject profile = context.get("profile");
  
  Tree tree = context.get("/schemaTree");
  NodeInfo root = (NodeInfo)tree.getModel().getRoot();
  
  if ( event == "init" )
  {
    if ( root.getText().equals("A Tree") )
    {
      // we are new and not in a refresh
      tree.setCellRenderer(new IconicCellRenderer("images/db.gif", "images/instance.gif", "images/table.gif"));
      root.setText(profile.get("user") + "@" + profile.get("host"));
      root.setIcon("instance");
    } 
    else 
    {
       tree.saveState();
    }
    root.removeAllChildren();
  }
  else if ( event == "backgroundTask" )
  {
    final DB db = new SQLLoggingDB((SQLLoggingDB)context.get("db"));
    worker.setProperty("db", db);
    worker.setProperty("waitOperation", "show databases");
    
    DB.AutoCleanupTX tx = new DB.AutoCleanupTX() {
      public void execute() 
      {
        String dbs = profile.get("dbs");
    
        String sql = null;
        if ( dbs == null || dbs.length() == 0 )
        {
           sql = "show databases";
        }
        else
        {
          String[] dbArray = dbs.split(";");
          sql = "show databases where `database` in (";
          String sep="";
          for (String aDb: dbArray)
          {
            sql+=sep+"'"+aDb + "'";
            sep=",";
          }
          sql+=")";
        }
        
        DB.Result databases = db.execute(sql);
        
        if ( "true".equals(profile.get("sort")))
        {
          Collections.sort(databases, databases.getComparator(0));
        }
        
        HashObject taskResult = new HashObject();
        taskResult.put("databases", databases);
        HashObject tableMap = new HashObject();
        taskResult.put("tables", tableMap);
    
        log.debug("database count:" + databases.size());
          
        for ( HashObject _dbs : databases )
        {
          String dbName = (String) _dbs.get(0);
          DB.Result tables = db.execute("show tables from `" + dbName + "`");
          tableMap.put(dbName, tables);
        }
        publish(taskResult);
      }
    };
    
    db.execute(tx);

  }
  else if ( event == "update" )
  {
    HashObject taskResult = (HashObject)((List)argObj("taskResult")).get(0);
    
    DB.Result databases = taskResult.getObject("databases");
    HashObject tableMap = taskResult.getObject("tables");
    
    HashObject dbNodes = null;
    
    dbNodes = TreeUtils.populateList(root, databases, 0, "db");
    
    for (String key: (Set<String>)tableMap.keySet())
    {
      DB.Result tables = tableMap.getObject(key);
      TreeUtils.populateList((NodeInfo)dbNodes.getObject(key), tables, 0, "table");
    }
    
    tree.updateUI();
    tree.restoreState();
  }
  else if ( event == "cancelled" ) 
  {
    DB db = worker.getProperty("db");
    if ( db != null )
    {
      db.cancel();
    }
  }