Class HistorianQueryExecutor

    • Method Detail

      • initialize

        public void initialize()
        Description copied from interface: HistoryQueryExecutor
        Initializes the query, performing any actions necessary to get the information required to run the query.
        Specified by:
        initialize in interface HistoryQueryExecutor
      • getColumnNodes

        public java.util.List<? extends HistoryNode> getColumnNodes()
        Description copied from interface: HistoryQueryExecutor
        Returns the HistoryNodes of this executor. There MUST be one for every tag path, and they must be in the same order as the paths provided to the executor when it was created. Also, these values must be available as soon as the executor is created. However, they won't be consulted for their data type until after initialize is called, so the normal procedure is to create and return DelegatingHistoryNodes, which get filled in later.
        Specified by:
        getColumnNodes in interface HistoryQueryExecutor
      • getEffectiveWindowSizeMS

        public int getEffectiveWindowSizeMS()
        Description copied from interface: HistoryQueryExecutor
        When "natural" results are requested, this will be called to let the query executors say what they think "natural" means. If a query executor does not support natural results, it should return -1. If all of the query executors return -1, a raw query will be performed.
        Specified by:
        getEffectiveWindowSizeMS in interface HistoryQueryExecutor
      • standardizePath

        protected java.lang.String standardizePath​(QualifiedPath p)
      • startReading

        public void startReading()
        Description copied from interface: HistoryQueryExecutor
        Begins reading data. IMPORTANT: endReading should always be called at some point after calling startReading.
        Specified by:
        startReading in interface HistoryQueryExecutor
      • endReading

        public void endReading()
        Description copied from interface: HistoryQueryExecutor
        If startReading was called, this function must be called (that is, it should be in a finally block).
        Specified by:
        endReading in interface HistoryQueryExecutor
      • hasMore

        public boolean hasMore()
        Description copied from interface: HistoryQueryExecutor
        Returns TRUE if there is more data available to be written on call to processData()
        Specified by:
        hasMore in interface HistoryQueryExecutor
      • moveForward

        protected void moveForward()
      • processData

        public long processData()
        Description copied from interface: HistoryQueryExecutor
        Puts the next value(s) into the appropriate column, returning the latest timestamp loaded, or -1 if no data was loaded.
        Specified by:
        processData in interface HistoryQueryExecutor