From 6d767220edb7a5c821b37834250bfd4d9ce562b7 Mon Sep 17 00:00:00 2001
From: aherbert <aherbert@apache.org>
Date: Fri, 2 Dec 2022 13:33:39 +0000
Subject: [PATCH] Use method reference to create a sampler

---
 .../AbstractIntegerDistribution.java          | 30 ++-----------------
 .../AbstractRealDistribution.java             | 30 ++-----------------
 2 files changed, 4 insertions(+), 56 deletions(-)

diff --git a/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/distribution/AbstractIntegerDistribution.java b/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/distribution/AbstractIntegerDistribution.java
index 15a7c5340..b18246022 100644
--- a/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/distribution/AbstractIntegerDistribution.java
+++ b/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/distribution/AbstractIntegerDistribution.java
@@ -23,8 +23,6 @@ import org.apache.commons.math4.legacy.exception.OutOfRangeException;
 import org.apache.commons.math4.legacy.exception.util.LocalizedFormats;
 import org.apache.commons.rng.UniformRandomProvider;
 import org.apache.commons.rng.sampling.distribution.InverseTransformDiscreteSampler;
-import org.apache.commons.rng.sampling.distribution.DiscreteInverseCumulativeProbabilityFunction;
-import org.apache.commons.rng.sampling.distribution.DiscreteSampler;
 import org.apache.commons.math4.core.jdkmath.JdkMath;
 
 /**
@@ -194,31 +192,7 @@ public abstract class AbstractIntegerDistribution
     /**{@inheritDoc} */
     @Override
     public DiscreteDistribution.Sampler createSampler(final UniformRandomProvider rng) {
-        return new DiscreteDistribution.Sampler() {
-            /**
-             * Inversion method distribution sampler.
-             */
-            private final DiscreteSampler sampler =
-                new InverseTransformDiscreteSampler(rng, createICPF());
-
-            /** {@inheritDoc} */
-            @Override
-            public int sample() {
-                return sampler.sample();
-            }
-        };
-    }
-
-    /**
-     * @return an instance for use by {@link #createSampler(UniformRandomProvider)}
-     */
-    private DiscreteInverseCumulativeProbabilityFunction createICPF() {
-        return new DiscreteInverseCumulativeProbabilityFunction() {
-            /** {@inheritDoc} */
-            @Override
-            public int inverseCumulativeProbability(double p) {
-                return AbstractIntegerDistribution.this.inverseCumulativeProbability(p);
-            }
-        };
+        // Inversion method distribution sampler.
+        return InverseTransformDiscreteSampler.of(rng, this::inverseCumulativeProbability)::sample;
     }
 }
diff --git a/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/distribution/AbstractRealDistribution.java b/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/distribution/AbstractRealDistribution.java
index 632d65461..30bfafb39 100644
--- a/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/distribution/AbstractRealDistribution.java
+++ b/commons-math-legacy/src/main/java/org/apache/commons/math4/legacy/distribution/AbstractRealDistribution.java
@@ -24,8 +24,6 @@ import org.apache.commons.math4.legacy.exception.OutOfRangeException;
 import org.apache.commons.math4.legacy.exception.util.LocalizedFormats;
 import org.apache.commons.rng.UniformRandomProvider;
 import org.apache.commons.rng.sampling.distribution.InverseTransformContinuousSampler;
-import org.apache.commons.rng.sampling.distribution.ContinuousInverseCumulativeProbabilityFunction;
-import org.apache.commons.rng.sampling.distribution.ContinuousSampler;
 import org.apache.commons.math4.core.jdkmath.JdkMath;
 
 /**
@@ -211,31 +209,7 @@ public abstract class AbstractRealDistribution
     /**{@inheritDoc} */
     @Override
     public ContinuousDistribution.Sampler createSampler(final UniformRandomProvider rng) {
-        return new ContinuousDistribution.Sampler() {
-            /**
-             * Inversion method distribution sampler.
-             */
-            private final ContinuousSampler sampler =
-                new InverseTransformContinuousSampler(rng, createICPF());
-
-            /** {@inheritDoc} */
-            @Override
-            public double sample() {
-                return sampler.sample();
-            }
-        };
-    }
-
-    /**
-     * @return an instance for use by {@link #createSampler(UniformRandomProvider)}
-     */
-    private ContinuousInverseCumulativeProbabilityFunction createICPF() {
-        return new ContinuousInverseCumulativeProbabilityFunction() {
-            /** {@inheritDoc} */
-            @Override
-            public double inverseCumulativeProbability(double p) {
-                return AbstractRealDistribution.this.inverseCumulativeProbability(p);
-            }
-        };
+        // Inversion method distribution sampler.
+        return InverseTransformContinuousSampler.of(rng, this::inverseCumulativeProbability)::sample;
     }
 }