AbstractRrdExecutionWriter.java

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package etm.contrib.rrd.core;

import etm.core.monitor.EtmPoint;

/**
 * Base implementation for RrdExecutionWriters.
 *
 * @author void.fm
 * @version $Revision$
 * @since 1.2.0
 */
public abstract class AbstractRrdExecutionWriter implements RrdExecutionWriter {

  protected long startInterval;
  protected long endInterval;
  protected long increment;

  protected int transactions;
  protected double min;
  protected double max;
  protected double total;

  protected AbstractRrdExecutionWriter(long aStartInterval, long aIncrement) {
    startInterval = aStartInterval;
    increment = aIncrement;
    endInterval = startInterval + increment;

    initAggregation();
  }

  public void onNextMeasurement(EtmPoint measurement) {
    long l = calculateTimestamp(measurement);

    //           A   B   C   D   E
    // start =  15   0  15  15  15
    // end =    20   5  20  20  20
    // l =     100  23  23  19  14

    // case A + B
    if (l > endInterval) {
      // case A and B
      if (startInterval == 0 || l > endInterval + increment) {
        startInterval = l;
        endInterval = startInterval + increment;
      } else {
        // case C
        flushStatus();
        // proceed to next interval
        startInterval = endInterval;
        endInterval = startInterval + increment;
      }
      initAggregation();
    }

    // case D
    if (l >= startInterval) {
      transactions++;
      double transactionTime = measurement.getTransactionTime();
      min = transactionTime < min ? transactionTime : min;
      max = transactionTime > max ? transactionTime : max;
      total += transactionTime;
    } // else case E, ingore, must be historical data

  }

  protected void initAggregation() {
    transactions = 0;
    total = 0;
    min = Double.MAX_VALUE;
    max = Double.MIN_VALUE;
  }

  protected abstract long calculateTimestamp(EtmPoint measurement);

  protected abstract void flushStatus();

}