Interface DataStore

  • All Superinterfaces:
    DataSink, HistoryStorer

    public interface DataStore
    extends DataSink
    A DataStore is an intermediate data sink - ie, the "store" part of "store and forward". Therefore, it takes data in as HistoricalData (through the DataSink interface), and then produces ForwardTransactions, which can be forwarded along.
    • Method Detail

      • addDataCountChangeListener

        void addDataCountChangeListener​(java.beans.PropertyChangeListener listener)
        Listener will be notified when new data is available for storage.
      • removeDataCountChangeListener

        void removeDataCountChangeListener​(java.beans.PropertyChangeListener listener)
      • getDataCount

        int getDataCount()
        Amount of data in the cache available to be forwarded. This value cannot be trusted to be 100% accurate, it could be an estimation, and could return negative values if the cache thinks nothing is available or does not yet know how many points are available.
      • getOldestTimestamp

        long getOldestTimestamp()
        Gets the timestamp of the oldest data, in order to calculate how long data has been present. Does not look at quarantined data. Returns Long.MaxValue if there is no value available (because that will be in the future, and thus not old).
      • takeNext

        @Nullable
        TransactionSet takeNext​(boolean wait,
                                int desiredTransactionSize,
                                @Nullable
                                java.util.Date olderThan)
                         throws java.lang.InterruptedException
        Gets the next set of transactions to run.
        Parameters:
        wait - whether to block until data is available. If false, or if an olderThan parameter is provided, will return null if no data is present.
        desiredTransactionSize - the desired size of data in the transactions. ONLY A HINT! Stores are free to return whatever they think is best. If -1, it's left to the store's discretion (usually will return 1 at a time)
        olderThan - If null, not used. Otherwise only returns data older than the given value. Returns null if there is no old data available.
        Throws:
        java.lang.InterruptedException