@Test
  public void testWriteWhenSamplingBegins() throws Exception {
    final TestStatisticsManager manager =
        new TestStatisticsManager(1, getUniqueName(), WRITER_INITIAL_DATE_MILLIS);

    final TestStatisticsSampler sampler = new TestStatisticsSampler(manager);
    final SampleCollector sampleCollector = new SampleCollector(sampler);

    final StatArchiveDescriptor archiveDescriptor =
        new StatArchiveDescriptor.Builder().setArchiveName(archiveFileName).setSystemId(1)
            .setSystemStartTime(WRITER_INITIAL_DATE_MILLIS - 2000)
            .setSystemDirectoryPath(testName.getMethodName())
            .setProductDescription(getClass().getSimpleName()).build();
    final StatArchiveWriter writer = new TestStatArchiveWriter(archiveDescriptor);
    sampleCollector.addSampleHandler(writer);

    long sampleTimeNanos = WRITER_PREVIOUS_TIMESTAMP_NANOS + NANOS_PER_MILLI * 1000;

    // 1) create ST1 and st1_1

    final StatisticDescriptor[] statsST1 =
        new StatisticDescriptor[] {manager.createDoubleCounter("double_counter_1", "d1", "u1"),
            manager.createDoubleCounter("double_counter_2", "d2", "u2", true),
            manager.createDoubleGauge("double_gauge_3", "d3", "u3"),
            manager.createDoubleGauge("double_gauge_4", "d4", "u4", false),
            manager.createIntCounter("int_counter_5", "d5", "u5"),
            manager.createIntCounter("int_counter_6", "d6", "u6", true),
            manager.createIntGauge("int_gauge_7", "d7", "u7"),
            manager.createIntGauge("int_gauge_8", "d8", "u8", false),
            manager.createLongCounter("long_counter_9", "d9", "u9"),
            manager.createLongCounter("long_counter_10", "d10", "u10", true),
            manager.createLongGauge("long_gauge_11", "d11", "u11"),
            manager.createLongGauge("long_gauge_12", "d12", "u12", false)};
    final StatisticsType ST1 = manager.createType("ST1", "ST1", statsST1);
    final Statistics st1_1 = manager.createAtomicStatistics(ST1, "st1_1", 1);

    // 2) create st1_2

    final Statistics st1_2 = manager.createAtomicStatistics(ST1, "st1_2", 2);

    // 3) some new values

    incDouble(st1_1, "double_counter_1", 18347.94880);
    incDouble(st1_1, "double_gauge_4", 24885.02346);
    incInt(st1_1, "int_counter_5", 3);
    incInt(st1_1, "int_gauge_8", 4);
    incLong(st1_1, "long_counter_9", 1073741824);
    incLong(st1_1, "long_gauge_12", 154367897);

    incDouble(st1_2, "double_counter_2", 346.95);
    incDouble(st1_2, "double_gauge_3", 9865.23008);
    incInt(st1_2, "int_counter_6", 4);
    incInt(st1_2, "int_gauge_7", 3);
    incLong(st1_2, "long_counter_10", 3497536);
    incLong(st1_2, "long_gauge_11", 103909646);

    sampleCollector.sample(sampleTimeNanos += (1000 * NANOS_PER_MILLI));

    // 4) all new values

    incDouble(st1_1, "double_counter_1", 1.098367);
    incDouble(st1_1, "double_counter_2", 50247.0983254);
    incDouble(st1_1, "double_gauge_3", 987654.2344);
    incDouble(st1_1, "double_gauge_4", 23.097);
    incInt(st1_1, "int_counter_5", 3);
    incInt(st1_1, "int_counter_6", 4);
    incInt(st1_1, "int_gauge_7", 3);
    incInt(st1_1, "int_gauge_8", 4);
    incLong(st1_1, "long_counter_9", 5);
    incLong(st1_1, "long_counter_10", 465793);
    incLong(st1_1, "long_gauge_11", -203050);
    incLong(st1_1, "long_gauge_12", 6);

    incDouble(st1_2, "double_counter_1", 0.000846643);
    incDouble(st1_2, "double_counter_2", 4.0);
    incDouble(st1_2, "double_gauge_3", -4.0);
    incDouble(st1_2, "double_gauge_4", 19276.0346624);
    incInt(st1_2, "int_counter_5", 1);
    incInt(st1_2, "int_counter_6", 2);
    incInt(st1_2, "int_gauge_7", -1);
    incInt(st1_2, "int_gauge_8", -2);
    incLong(st1_2, "long_counter_9", 309876);
    incLong(st1_2, "long_counter_10", 4);
    incLong(st1_2, "long_gauge_11", -4);
    incLong(st1_2, "long_gauge_12", 1098764);

    sampleCollector.sample(sampleTimeNanos += (1000 * NANOS_PER_MILLI));

    // 5) no new values

    sampleCollector.sample(sampleTimeNanos += (1000 * NANOS_PER_MILLI));

    // 6) some new values

    incDouble(st1_1, "double_counter_2", 10.255);
    incDouble(st1_1, "double_gauge_3", -4123.05);
    incInt(st1_1, "int_counter_6", 2);
    incInt(st1_1, "int_gauge_7", 3);
    incLong(st1_1, "long_counter_10", 4);
    incLong(st1_1, "long_gauge_11", -2);

    incDouble(st1_2, "double_counter_1", 5.00007634);
    incDouble(st1_2, "double_gauge_4", 16904.06524);
    incInt(st1_2, "int_counter_5", 4);
    incInt(st1_2, "int_gauge_8", 1);
    incLong(st1_2, "long_counter_9", 8);
    incLong(st1_2, "long_gauge_12", 10);

    sampleCollector.sample(sampleTimeNanos += (1000 * NANOS_PER_MILLI));

    // 7) all new values

    incDouble(st1_1, "double_counter_1", 4065.340);
    incDouble(st1_1, "double_counter_2", 2.01342568);
    incDouble(st1_1, "double_gauge_3", 1.367890);
    incDouble(st1_1, "double_gauge_4", 8.0549003);
    incInt(st1_1, "int_counter_5", 2);
    incInt(st1_1, "int_counter_6", 9);
    incInt(st1_1, "int_gauge_7", 1);
    incInt(st1_1, "int_gauge_8", 2);
    incLong(st1_1, "long_counter_9", 6);
    incLong(st1_1, "long_counter_10", 2);
    incLong(st1_1, "long_gauge_11", -10);
    incLong(st1_1, "long_gauge_12", 8);

    incDouble(st1_2, "double_counter_1", 128.2450);
    incDouble(st1_2, "double_counter_2", 113.550);
    incDouble(st1_2, "double_gauge_3", 21.0676);
    incDouble(st1_2, "double_gauge_4", 2.01346);
    incInt(st1_2, "int_counter_5", 3);
    incInt(st1_2, "int_counter_6", 4);
    incInt(st1_2, "int_gauge_7", 4);
    incInt(st1_2, "int_gauge_8", 2);
    incLong(st1_2, "long_counter_9", 1);
    incLong(st1_2, "long_counter_10", 2);
    incLong(st1_2, "long_gauge_11", 3);
    incLong(st1_2, "long_gauge_12", -2);

    sampleCollector.sample(sampleTimeNanos += (1000 * NANOS_PER_MILLI));

    // 8) create ST2 and ST3 and st2_1 and st3_1 and st3_2

    final StatisticDescriptor[] statsST2 =
        new StatisticDescriptor[] {manager.createIntGauge("int_gauge_7", "d7", "u7"),
            manager.createIntGauge("int_gauge_8", "d8", "u8", false),
            manager.createLongCounter("long_counter_9", "d9", "u9"),
            manager.createLongCounter("long_counter_10", "d10", "u10", true),
            manager.createLongGauge("long_gauge_11", "d11", "u11"),
            manager.createLongGauge("long_gauge_12", "d12", "u12", false)};
    final StatisticsType ST2 = manager.createType("ST2", "ST2", statsST2);
    final Statistics st2_1 = manager.createAtomicStatistics(ST2, "st2_1", 1);

    final StatisticDescriptor[] statsST3 =
        new StatisticDescriptor[] {manager.createDoubleCounter("double_counter_1", "d1", "u1"),
            manager.createDoubleCounter("double_counter_2", "d2", "u2", true),
            manager.createDoubleGauge("double_gauge_3", "d3", "u3"),
            manager.createDoubleGauge("double_gauge_4", "d4", "u4", false),
            manager.createIntCounter("int_counter_5", "d5", "u5"),
            manager.createIntCounter("int_counter_6", "d6", "u6", true),};
    final StatisticsType ST3 = manager.createType("ST3", "ST3", statsST3);
    final Statistics st3_1 = manager.createAtomicStatistics(ST3, "st3_1", 1);
    final Statistics st3_2 = manager.createAtomicStatistics(ST3, "st3_2", 2);

    // 9) all new values

    incDouble(st1_1, "double_counter_1", 9499.10);
    incDouble(st1_1, "double_counter_2", 83.0);
    incDouble(st1_1, "double_gauge_3", -7.05678);
    incDouble(st1_1, "double_gauge_4", 5111.031);
    incInt(st1_1, "int_counter_5", 1);
    incInt(st1_1, "int_counter_6", 3);
    incInt(st1_1, "int_gauge_7", 9);
    incInt(st1_1, "int_gauge_8", -3);
    incLong(st1_1, "long_counter_9", 3);
    incLong(st1_1, "long_counter_10", 8);
    incLong(st1_1, "long_gauge_11", 5);
    incLong(st1_1, "long_gauge_12", 4);

    incDouble(st1_2, "double_counter_1", 2509.0235);
    incDouble(st1_2, "double_counter_2", 409.10063);
    incDouble(st1_2, "double_gauge_3", -42.66904);
    incDouble(st1_2, "double_gauge_4", 21.0098);
    incInt(st1_2, "int_counter_5", 8);
    incInt(st1_2, "int_counter_6", 9);
    incInt(st1_2, "int_gauge_7", -2);
    incInt(st1_2, "int_gauge_8", 6);
    incLong(st1_2, "long_counter_9", 4);
    incLong(st1_2, "long_counter_10", 5);
    incLong(st1_2, "long_gauge_11", 5);
    incLong(st1_2, "long_gauge_12", -1);

    incInt(st2_1, "int_gauge_7", 2);
    incInt(st2_1, "int_gauge_8", -1);
    incLong(st2_1, "long_counter_9", 1002948);
    incLong(st2_1, "long_counter_10", 29038856);
    incLong(st2_1, "long_gauge_11", -2947465);
    incLong(st2_1, "long_gauge_12", 4934745);

    incDouble(st3_1, "double_counter_1", 562.0458);
    incDouble(st3_1, "double_counter_2", 14.0086);
    incDouble(st3_1, "double_gauge_3", -2.0);
    incDouble(st3_1, "double_gauge_4", 1.0);
    incInt(st3_1, "int_counter_5", 2);
    incInt(st3_1, "int_counter_6", 1);

    incDouble(st3_2, "double_counter_1", 33.087);
    incDouble(st3_2, "double_counter_2", 2.02);
    incDouble(st3_2, "double_gauge_3", 1.06);
    incDouble(st3_2, "double_gauge_4", 3.021);
    incInt(st3_2, "int_counter_5", 1);
    incInt(st3_2, "int_counter_6", 4);

    sampleCollector.sample(sampleTimeNanos += (1000 * NANOS_PER_MILLI));

    // 10) some new values

    incDouble(st1_1, "double_counter_1", 3.014);
    incDouble(st1_1, "double_gauge_3", 57.003);
    incInt(st1_1, "int_counter_5", 3);
    incInt(st1_1, "int_gauge_7", 5);
    incLong(st1_1, "long_counter_9", 1);
    incLong(st1_1, "long_gauge_11", 1);

    incDouble(st1_2, "double_counter_2", 20.107);
    incDouble(st1_2, "double_gauge_4", 1.5078);
    incInt(st1_2, "int_counter_6", 1);
    incInt(st1_2, "int_gauge_8", -1);
    incLong(st1_2, "long_counter_10", 1073741824);
    incLong(st1_2, "long_gauge_12", 5);

    incInt(st2_1, "int_gauge_7", 2);
    incLong(st2_1, "long_counter_9", 2);
    incLong(st2_1, "long_gauge_11", -2);

    incDouble(st3_1, "double_counter_1", 24.80097);
    incDouble(st3_1, "double_gauge_3", -22.09834);
    incInt(st3_1, "int_counter_5", 2);

    incDouble(st3_2, "double_counter_2", 21.0483);
    incDouble(st3_2, "double_gauge_4", 36310.012);
    incInt(st3_2, "int_counter_6", 4);

    sampleCollector.sample(sampleTimeNanos += (1000 * NANOS_PER_MILLI));

    // 11) remove ST2 and st2_1

    manager.destroyStatistics(st2_1);

    // 12) some new values

    incDouble(st1_1, "double_counter_1", 339.0803);
    incDouble(st1_1, "double_counter_2", 21.06);
    incDouble(st1_1, "double_gauge_3", 12.056);
    incDouble(st1_1, "double_gauge_4", 27.108);
    incInt(st1_1, "int_counter_5", 2);
    incInt(st1_1, "int_counter_6", 4);

    incInt(st1_2, "int_gauge_7", 4);
    incInt(st1_2, "int_gauge_8", 7);
    incLong(st1_2, "long_counter_9", 8);
    incLong(st1_2, "long_counter_10", 4);
    incLong(st1_2, "long_gauge_11", 2);
    incLong(st1_2, "long_gauge_12", 1);

    incDouble(st3_1, "double_counter_1", 41.103);
    incDouble(st3_1, "double_counter_2", 2.0333);
    incDouble(st3_1, "double_gauge_3", -14.0);

    incDouble(st3_2, "double_gauge_4", 26.01);
    incInt(st3_2, "int_counter_5", 3);
    incInt(st3_2, "int_counter_6", 1);

    sampleCollector.sample(sampleTimeNanos += (1000 * NANOS_PER_MILLI));

    // 13) no new values

    sampleCollector.sample(sampleTimeNanos += (1000 * NANOS_PER_MILLI));

    // 14) remove st1_2

    manager.destroyStatistics(st1_2);

    // 15) all new values

    incDouble(st1_1, "double_counter_1", 62.1350);
    incDouble(st1_1, "double_counter_2", 33.306);
    incDouble(st1_1, "double_gauge_3", 41.1340);
    incDouble(st1_1, "double_gauge_4", -1.04321);
    incInt(st1_1, "int_counter_5", 2);
    incInt(st1_1, "int_counter_6", 2);
    incInt(st1_1, "int_gauge_7", 1);
    incInt(st1_1, "int_gauge_8", 9);
    incLong(st1_1, "long_counter_9", 2);
    incLong(st1_1, "long_counter_10", 5);
    incLong(st1_1, "long_gauge_11", 3);
    incLong(st1_1, "long_gauge_12", -2);

    incDouble(st3_1, "double_counter_1", 3461.0153);
    incDouble(st3_1, "double_counter_2", 5.03167);
    incDouble(st3_1, "double_gauge_3", -1.31051);
    incDouble(st3_1, "double_gauge_4", 71.031);
    incInt(st3_1, "int_counter_5", 4);
    incInt(st3_1, "int_counter_6", 2);

    incDouble(st3_2, "double_counter_1", 531.5608);
    incDouble(st3_2, "double_counter_2", 55.0532);
    incDouble(st3_2, "double_gauge_3", 8.40956);
    incDouble(st3_2, "double_gauge_4", 23230.0462);
    incInt(st3_2, "int_counter_5", 9);
    incInt(st3_2, "int_counter_6", 5);

    sampleCollector.sample(sampleTimeNanos += (1000 * NANOS_PER_MILLI));

    // close the writer

    writer.close();

    // print out all the stat values

    if (false) {
      StatisticDescriptor[] sds = ST1.getStatistics();
      for (final StatisticDescriptor item : sds) {
        logger.info("testWriteAfterSamplingBegins#st1_1#" + item.getName() + "="
            + st1_1.get(item.getName()));
      }
      for (final StatisticDescriptor value : sds) {
        logger.info("testWriteAfterSamplingBegins#st1_2#" + value.getName() + "="
            + st1_2.get(value.getName()));
      }

      sds = ST2.getStatistics();
      for (final StatisticDescriptor descriptor : sds) {
        logger.info("testWriteAfterSamplingBegins#st2_1#" + descriptor.getName() + "="
            + st2_1.get(descriptor.getName()));
      }

      sds = ST3.getStatistics();
      for (final StatisticDescriptor statisticDescriptor : sds) {
        logger.info("testWriteAfterSamplingBegins#st3_1#" + statisticDescriptor.getName() + "="
            + st3_1.get(statisticDescriptor.getName()));
      }
      for (final StatisticDescriptor sd : sds) {
        logger.info("testWriteAfterSamplingBegins#st3_2#" + sd.getName() + "="
            + st3_2.get(sd.getName()));
      }
    }

    // validate that stat archive file exists

    final File actual = new File(archiveFileName);
    assertTrue(actual.exists());

    // validate content of stat archive file using StatArchiveReader

    final StatArchiveReader reader = new StatArchiveReader(new File[] {actual}, null, false);

    // compare all resourceInst values against what was printed above

    final List resources = reader.getResourceInstList();
    for (final Object resource : resources) {
      final StatArchiveReader.ResourceInst ri = (StatArchiveReader.ResourceInst) resource;
      final String resourceName = ri.getName();
      assertNotNull(resourceName);

      final String expectedStatsType = statisticTypes.get(resourceName);
      assertNotNull(expectedStatsType);
      assertEquals(expectedStatsType, ri.getType().getName());

      final Map<String, Number> expectedStatValues = allStatistics.get(resourceName);
      assertNotNull(expectedStatValues);

      final StatValue[] statValues = ri.getStatValues();
      for (int i = 0; i < statValues.length; i++) {
        final String statName = ri.getType().getStats()[i].getName();
        assertNotNull(statName);
        assertNotNull(expectedStatValues.get(statName));

        assertEquals(statName, statValues[i].getDescriptor().getName());

        statValues[i].setFilter(StatValue.FILTER_NONE);
        final double[] rawSnapshots = statValues[i].getRawSnapshots();
        // for (int j = 0; j < rawSnapshots.length; j++) {
        // logger.info("DEBUG " + ri.getName() + " " + statName + " rawSnapshots[" + j + "] = " +
        // rawSnapshots[j]);
        // }
        assertEquals("Value " + i + " for " + statName + " is wrong: " + expectedStatValues,
            expectedStatValues.get(statName).doubleValue(), statValues[i].getSnapshotsMostRecent(),
            0.01);
      }
    }

    // validate byte content of stat archive file against saved expected file

    final File expected = new File(createTempFileFromResource(getClass(),
        "StatArchiveWriterReaderJUnitTest_" + testName.getMethodName() + "_expected.gfs")
            .getAbsolutePath());
    assertTrue(expected + " does not exist!", expected.exists());
    assertEquals(expected.length(), actual.length());

    assertTrue("Actual stat archive file: " + actual.getAbsolutePath()
        + " bytes differ from expected stat archive file bytes!",
        Arrays.equals(readBytes(expected), readBytes(actual)));
  }
Tests the stat archive file written by StatArchiveWriter.
geode-core/src/integrationTest/java/org/apache/geode/internal/statistics/StatArchiveWriterReaderIntegrationTest.java