pmd fix: add FunctionalInterface annotation

Author: aherbert

commons-rng-client-api/src/main/java/org/apache/commons/rng/UniformRandomProvider.java

@@ -26,6 +26,7 @@
  *
  * @since 1.0
  */
+@FunctionalInterface
 public interface UniformRandomProvider {
     /**
      * Generates {@code byte} values and places them into a user-supplied array.

commons-rng-core/src/main/java/org/apache/commons/rng/core/source32/RandomIntSource.java

@@ -22,6 +22,7 @@
  *
  * @since 1.0
  */
+@FunctionalInterface
 public interface RandomIntSource {
     /**
      * Return the next random value.

commons-rng-core/src/main/java/org/apache/commons/rng/core/source64/RandomLongSource.java

@@ -22,6 +22,7 @@
  *
  * @since 1.0
  */
+@FunctionalInterface
 public interface RandomLongSource {
     /**
      * Return the next random value.

commons-rng-core/src/main/java/org/apache/commons/rng/core/util/RandomStreams.java

@@ -40,6 +40,7 @@ public final class RandomStreams {
      * @param <T> the object type
      * @since 1.5
      */
+    @FunctionalInterface
     public interface SeededObjectFactory<T> {
         /**
          * Creates the object.

commons-rng-sampling/src/main/java/org/apache/commons/rng/sampling/CompositeSamplers.java

@@ -73,6 +73,7 @@ public final class CompositeSamplers {
      * <a href="http://en.wikipedia.org/wiki/Probability_distribution#Discrete_probability_distribution">
      * discrete probability distribution</a>.
      */
+    @FunctionalInterface
     public interface DiscreteProbabilitySamplerFactory {
         /**
          * Creates the sampler.
@@ -273,6 +274,7 @@ enum Specialisation {
          *
          * @param <S> Type of sampler
          */
+        @FunctionalInterface
         interface SamplerFactory<S> {
             /**
              * Creates a new composite sampler.

commons-rng-sampling/src/main/java/org/apache/commons/rng/sampling/ObjectSampler.java

@@ -25,6 +25,7 @@
  * @param <T> Type of the sample.
  * @since 1.4
  */
+@FunctionalInterface
 public interface ObjectSampler<T> {
     /**
      * Create an object sample.

commons-rng-sampling/src/main/java/org/apache/commons/rng/sampling/SharedStateSampler.java

@@ -26,6 +26,7 @@
  * @param <R> Type of the sampler.
  * @since 1.3
  */
+@FunctionalInterface
 public interface SharedStateSampler<R> {
     /**
      * Create a new instance of the sampler with the same underlying state using the given

commons-rng-sampling/src/main/java/org/apache/commons/rng/sampling/distribution/ContinuousInverseCumulativeProbabilityFunction.java

@@ -23,6 +23,7 @@
  *
  * @since 1.0
  */
+@FunctionalInterface
 public interface ContinuousInverseCumulativeProbabilityFunction {
     /**
      * Computes the quantile function of the distribution.

commons-rng-sampling/src/main/java/org/apache/commons/rng/sampling/distribution/ContinuousSampler.java

@@ -23,6 +23,7 @@
  *
  * @since 1.0
  */
+@FunctionalInterface
 public interface ContinuousSampler {
     /**
      * Creates a {@code double} sample.

commons-rng-sampling/src/main/java/org/apache/commons/rng/sampling/distribution/DiscreteInverseCumulativeProbabilityFunction.java

@@ -23,6 +23,7 @@
  *
  * @since 1.0
  */
+@FunctionalInterface
 public interface DiscreteInverseCumulativeProbabilityFunction {
     /**
      * Computes the quantile function of the distribution.