code: public TableSchema getTableSchemaFromName(String tableName, DbUser user) throws Exception {
  		List<String> tableNames = new Vector<String>();
  		tableNames.add(tableName);
  		
  		Map<String,TableSchemaImpl> nameToTableMap = getTableDataFromGroups(user,tableNames);
  		
  		if( false == nameToTableMap.containsKey(tableName) ) {
  			throw new Exception("A table named '"+tableName+"' does not exist or is not available");
  		}
  
  		return nameToTableMap.get(tableName);
  	}
docs: Computes from the database the access to a table for a given user. In
  this call, a user is represented by the set of groups it belongs to.
  @param tableName Name of the table to be queried
  @param user User requesting access to the schema
  @return An object that represents available access to a table. Null if the table
  not available.
  @throws Exception