diff --git a/java/google/registry/monitoring/metrics/FibonacciFitter.java b/java/google/registry/monitoring/metrics/FibonacciFitter.java new file mode 100644 index 000000000..c03a2cdc6 --- /dev/null +++ b/java/google/registry/monitoring/metrics/FibonacciFitter.java @@ -0,0 +1,64 @@ +// Copyright 2017 The Nomulus Authors. All Rights Reserved. +// +// 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 google.registry.monitoring.metrics; + +import static com.google.common.base.Preconditions.checkArgument; + +import com.google.auto.value.AutoValue; +import com.google.common.collect.ImmutableSortedSet; + +/** + * A {@link DistributionFitter} with intervals of increasing size using the Fibonacci sequence. + * + *

A Fibonacci fitter is useful in situations where you want more precision on the low end than + * an {@link ExponentialFitter} with exponent base 2 would provide without the hassle of dealing + * with non-integer boundaries, such as would be created by an exponential fitter with a base of + * less than 2. Fibonacci fitters are ideal for integer metrics that are bounded across a certain + * range, e.g. integers between 1 and 1,000. + * + *

The interval boundaries are chosen as {@code (-inf, 0), [0, 1), [1, 2), [2, 3), [3, 5), [5, + * 8), [8, 13)}, etc., up to {@code [fibonacciFloor(maxBucketSize), inf)}. + */ +@AutoValue +public abstract class FibonacciFitter implements DistributionFitter { + + /** + * Returns a new {@link FibonacciFitter}. + * + * @param maxBucketSize the maximum bucket size to create (rounded down to the nearest Fibonacci + * number) + * @throws IllegalArgumentException if {@code maxBucketSize <= 0} + */ + public static FibonacciFitter create(long maxBucketSize) { + checkArgument(maxBucketSize > 0, "maxBucketSize must be greater than 0"); + + ImmutableSortedSet.Builder boundaries = ImmutableSortedSet.naturalOrder(); + boundaries.add(Double.valueOf(0)); + long i = 1; + long j = 2; + long k = 3; + while (i <= maxBucketSize) { + boundaries.add(Double.valueOf(i)); + i = j; + j = k; + k = i + j; + } + + return new AutoValue_FibonacciFitter(boundaries.build()); + } + + @Override + public abstract ImmutableSortedSet boundaries(); +} diff --git a/javatests/google/registry/monitoring/metrics/ExponentialFitterTest.java b/javatests/google/registry/monitoring/metrics/ExponentialFitterTest.java index 8790e5b66..df80e9d7b 100644 --- a/javatests/google/registry/monitoring/metrics/ExponentialFitterTest.java +++ b/javatests/google/registry/monitoring/metrics/ExponentialFitterTest.java @@ -22,7 +22,7 @@ import org.junit.rules.ExpectedException; import org.junit.runner.RunWith; import org.junit.runners.JUnit4; -/** Tests for implementations of {@link DistributionFitter}. */ +/** Unit tests for {@link ExponentialFitter}. */ @RunWith(JUnit4.class) public class ExponentialFitterTest { diff --git a/javatests/google/registry/monitoring/metrics/FibonacciFitterTest.java b/javatests/google/registry/monitoring/metrics/FibonacciFitterTest.java new file mode 100644 index 000000000..7b2d57ade --- /dev/null +++ b/javatests/google/registry/monitoring/metrics/FibonacciFitterTest.java @@ -0,0 +1,83 @@ +// Copyright 2017 The Nomulus Authors. All Rights Reserved. +// +// 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 google.registry.monitoring.metrics; + +import static com.google.common.truth.Truth.assertThat; +import static org.junit.Assert.fail; + +import com.google.common.collect.ImmutableList; +import org.junit.Test; +import org.junit.runner.RunWith; +import org.junit.runners.JUnit4; + +/** Unit tests for {@link FibonacciFitter}. */ +@RunWith(JUnit4.class) +public class FibonacciFitterTest { + + @Test + public void testCreate_maxBucketSizeNegative_throwsException() { + try { + FibonacciFitter.create(-1); + fail("Expected exception"); + } catch (IllegalArgumentException e) { + assertThat(e).hasMessageThat().isEqualTo("maxBucketSize must be greater than 0"); + } + } + + @Test + public void testCreate_maxBucketSizeZero_throwsException() { + try { + FibonacciFitter.create(0); + fail("Expected exception"); + } catch (IllegalArgumentException e) { + assertThat(e).hasMessageThat().isEqualTo("maxBucketSize must be greater than 0"); + } + } + + @Test + public void testCreate_maxBucketSizeOne_createsTwoBoundaries() { + assertThat(FibonacciFitter.create(1).boundaries()).containsExactly(0.0, 1.0).inOrder(); + } + + @Test + public void testCreate_maxBucketSizeTwo_createsThreeBoundaries() { + assertThat(FibonacciFitter.create(2).boundaries()).containsExactly(0.0, 1.0, 2.0).inOrder(); + } + + @Test + public void testCreate_maxBucketSizeThree_createsFourBoundaries() { + assertThat(FibonacciFitter.create(3).boundaries()) + .containsExactly(0.0, 1.0, 2.0, 3.0) + .inOrder(); + } + + @Test + public void testCreate_maxBucketSizeFour_createsFourBoundaries() { + assertThat(FibonacciFitter.create(4).boundaries()) + .containsExactly(0.0, 1.0, 2.0, 3.0) + .inOrder(); + } + + @Test + public void testCreate_maxBucketSizeLarge_createsFibonacciSequenceBoundaries() { + ImmutableList expectedBoundaries = + ImmutableList.of( + 0.0, 1.0, 2.0, 3.0, 5.0, 8.0, 13.0, 21.0, 34.0, 55.0, 89.0, 144.0, 233.0, 377.0, 610.0, + 987.0); + assertThat(FibonacciFitter.create(1000).boundaries()) + .containsExactlyElementsIn(expectedBoundaries) + .inOrder(); + } +} diff --git a/javatests/google/registry/monitoring/metrics/LinearFitterTest.java b/javatests/google/registry/monitoring/metrics/LinearFitterTest.java index 8716f2597..8955029eb 100644 --- a/javatests/google/registry/monitoring/metrics/LinearFitterTest.java +++ b/javatests/google/registry/monitoring/metrics/LinearFitterTest.java @@ -22,7 +22,7 @@ import org.junit.rules.ExpectedException; import org.junit.runner.RunWith; import org.junit.runners.JUnit4; -/** Tests for {@link LinearFitter}. */ +/** Unit tests for {@link LinearFitter}. */ @RunWith(JUnit4.class) public class LinearFitterTest {