Adds P75 Statistic to list of available percentile statistics. (#71)

Added support for a 75th Percentile statistic

Author: ddimensia

src/main/java/com/arpnetworking/tsdcore/statistics/TP75Statistic.java

@@ -0,0 +1,33 @@
+/**
+ * Copyright 2017 Dropbox, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.arpnetworking.tsdcore.statistics;
+
+import com.arpnetworking.logback.annotations.Loggable;
+
+/**
+ * Top 75th percentile statistic. Use <code>StatisticFactory</code> for construction.
+ *
+ * @author Gilligan Markham (gmarkham at dropbox dot com)
+ */
+@Loggable
+public final class TP75Statistic extends TPStatistic {
+
+    private TP75Statistic() {
+        super(75d);
+    }
+
+    private static final long serialVersionUID = 1;
+}

src/test/java/com/arpnetworking/tsdcore/statistics/StatisticFactoryTest.java

@@ -47,6 +47,7 @@ public static Collection<Object[]> createParameters() {
                 a(l("count", "n"), CountStatistic.class),
                 a(l("p0", "tp0", "min"), MinStatistic.class),
                 a(l("p50", "tp50", "median"), MedianStatistic.class),
+                a(l("p75", "tp75"), TP75Statistic.class),
                 a(l("p90", "tp90"), TP90Statistic.class),
                 a(l("p95", "tp95"), TP95Statistic.class),
                 a(l("p99", "tp99"), TP99Statistic.class),

src/test/java/com/arpnetworking/tsdcore/statistics/TPStatisticTest.java

@@ -34,6 +34,7 @@ public class TPStatisticTest {
 
     @Test
     public void testName() {
+        Assert.assertEquals("tp75", TP75_STATISTIC.getName());
         Assert.assertEquals("tp90", TP90_STATISTIC.getName());
         Assert.assertEquals("tp95", TP95_STATISTIC.getName());
         Assert.assertEquals("tp99", TP99_STATISTIC.getName());
@@ -42,6 +43,10 @@ public void testName() {
 
     @Test
     public void testEquality() {
+        Assert.assertFalse(TP75_STATISTIC.equals(null));
+        Assert.assertFalse(TP75_STATISTIC.equals("ABC"));
+        Assert.assertTrue(TP75_STATISTIC.equals(TP75_STATISTIC));
+
         Assert.assertFalse(TP90_STATISTIC.equals(null));
         Assert.assertFalse(TP90_STATISTIC.equals("ABC"));
         Assert.assertTrue(TP90_STATISTIC.equals(TP90_STATISTIC));
@@ -61,12 +66,24 @@ public void testEquality() {
 
     @Test
     public void testHashCode() {
+        Assert.assertEquals(TP75_STATISTIC.hashCode(), TP75_STATISTIC.hashCode());
         Assert.assertEquals(TP90_STATISTIC.hashCode(), TP90_STATISTIC.hashCode());
         Assert.assertEquals(TP95_STATISTIC.hashCode(), TP95_STATISTIC.hashCode());
         Assert.assertEquals(TP99_STATISTIC.hashCode(), TP99_STATISTIC.hashCode());
         Assert.assertEquals(TP99P9_STATISTIC.hashCode(), TP99P9_STATISTIC.hashCode());
     }
 
+    @Test
+    public void testTP75Accumulator() {
+        final Accumulator<?> accumulator = (Accumulator<?>) HISTOGRAM_STATISTIC.createCalculator();
+        for (int x = 1; x <= 10000; ++x) {
+            accumulator.accumulate(new Quantity.Builder().setValue((double) x).build());
+        }
+        final CalculatedValue<Void> calculated = TP75_STATISTIC.createCalculator().calculate(
+                Collections.singletonMap(HISTOGRAM_STATISTIC, accumulator));
+        Assert.assertTrue(areClose(new Quantity.Builder().setValue(7500.0).build(), calculated.getValue()));
+    }
+
     @Test
     public void testTP90Accumulator() {
         final Accumulator<?> accumulator = (Accumulator<?>) HISTOGRAM_STATISTIC.createCalculator();
@@ -132,6 +149,7 @@ private boolean areClose(final Quantity expected, final Quantity actual) {
     private static final List<Double> ONE_TO_FIVE = Lists.newArrayList(1d, 2d, 3d, 4d, 5d);
     private static final StatisticFactory STATISTIC_FACTORY = new StatisticFactory();
     private static final Statistic HISTOGRAM_STATISTIC = STATISTIC_FACTORY.getStatistic("histogram");
+    private static final TP75Statistic TP75_STATISTIC = (TP75Statistic) STATISTIC_FACTORY.getStatistic("tp75");
     private static final TP90Statistic TP90_STATISTIC = (TP90Statistic) STATISTIC_FACTORY.getStatistic("tp90");
     private static final TP95Statistic TP95_STATISTIC = (TP95Statistic) STATISTIC_FACTORY.getStatistic("tp95");
     private static final TP99Statistic TP99_STATISTIC = (TP99Statistic) STATISTIC_FACTORY.getStatistic("tp99");