Refactored target array allocation in the various SequenceSampler implementations

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 * Refactored Permutation.equals() method (non-breaking).
+* Refactored target array allocation in the various SequenceSampler implementations (non-breaking).
 
 ### Deprecated
 

pom.xml

@@ -230,6 +230,9 @@
 				<version>3.15.0</version>
 				<configuration>
 					<release>25</release>
+                    <compilerArgs>
+                        <arg>-Xlint:unchecked</arg>
+                    </compilerArgs>
 				</configuration>
 			</plugin>
 			<plugin>

src/main/java/org/cicirello/sequences/SequenceInsertionSampler.java

@@ -1,6 +1,6 @@
 /*
  * JavaPermutationTools: A Java library for computation on permutations and sequences
- * Copyright 2005-2023 Vincent A. Cicirello, <https://www.cicirello.org/>.
+ * Copyright 2005-2026 Vincent A. Cicirello, <https://www.cicirello.org/>.
  *
  * This file is part of JavaPermutationTools (https://jpt.cicirello.org/).
  *
@@ -222,7 +222,8 @@ public char[] nextSample(String source, int k, char[] target) {
   @Override
   public <T> T[] nextSample(T[] source, int k, T[] target) {
     SequenceSamplerUtils.validateK(k, source.length);
-    target = SequenceSamplerUtils.allocateIfNecessary(source, k, target);
+    target =
+        SequenceSamplerUtils.allocateIfNecessary(source.getClass().getComponentType(), k, target);
     int[] indexes = r.sampleInsertion(source.length, k, null);
     for (int i = 0; i < k; i++) {
       target[i] = source[indexes[i]];
@@ -595,7 +596,8 @@ public static float[] sample(float[] source, int k, float[] target, RandomGenera
    */
   public static <T> T[] sample(T[] source, int k, T[] target, RandomGenerator r) {
     SequenceSamplerUtils.validateK(k, source.length);
-    target = SequenceSamplerUtils.allocateIfNecessary(source, k, target);
+    target =
+        SequenceSamplerUtils.allocateIfNecessary(source.getClass().getComponentType(), k, target);
     int[] indexes = RandomSampler.sampleInsertion(source.length, k, null, r);
     for (int i = 0; i < k; i++) {
       target[i] = source[indexes[i]];

src/main/java/org/cicirello/sequences/SequencePoolSampler.java

@@ -1,6 +1,6 @@
 /*
  * JavaPermutationTools: A Java library for computation on permutations and sequences
- * Copyright 2005-2023 Vincent A. Cicirello, <https://www.cicirello.org/>.
+ * Copyright 2005-2026 Vincent A. Cicirello, <https://www.cicirello.org/>.
  *
  * This file is part of JavaPermutationTools (https://jpt.cicirello.org/).
  *
@@ -247,7 +247,8 @@ public char[] nextSample(String source, int k, char[] target) {
   @Override
   public <T> T[] nextSample(T[] source, int k, T[] target) {
     SequenceSamplerUtils.validateK(k, source.length);
-    target = SequenceSamplerUtils.allocateIfNecessary(source, k, target);
+    target =
+        SequenceSamplerUtils.allocateIfNecessary(source.getClass().getComponentType(), k, target);
     T[] pool = Arrays.copyOf(source, source.length);
     int remaining = pool.length;
     for (int i = 0; i < k; i++) {
@@ -653,7 +654,8 @@ public static float[] sample(float[] source, int k, float[] target, RandomGenera
    */
   public static <T> T[] sample(T[] source, int k, T[] target, RandomGenerator r) {
     SequenceSamplerUtils.validateK(k, source.length);
-    target = SequenceSamplerUtils.allocateIfNecessary(source, k, target);
+    target =
+        SequenceSamplerUtils.allocateIfNecessary(source.getClass().getComponentType(), k, target);
     T[] pool = Arrays.copyOf(source, source.length);
     int remaining = pool.length;
     for (int i = 0; i < k; i++) {

src/main/java/org/cicirello/sequences/SequenceReservoirSampler.java

@@ -1,6 +1,6 @@
 /*
  * JavaPermutationTools: A Java library for computation on permutations and sequences
- * Copyright 2005-2023 Vincent A. Cicirello, <https://www.cicirello.org/>.
+ * Copyright 2005-2026 Vincent A. Cicirello, <https://www.cicirello.org/>.
  *
  * This file is part of JavaPermutationTools (https://jpt.cicirello.org/).
  *
@@ -237,7 +237,8 @@ public char[] nextSample(String source, int k, char[] target) {
   @Override
   public <T> T[] nextSample(T[] source, int k, T[] target) {
     SequenceSamplerUtils.validateK(k, source.length);
-    target = SequenceSamplerUtils.allocateIfNecessary(source, k, target);
+    target =
+        SequenceSamplerUtils.allocateIfNecessary(source.getClass().getComponentType(), k, target);
     System.arraycopy(source, 0, target, 0, k);
     for (int i = k; i < source.length; i++) {
       int j = r.nextInt(i + 1);
@@ -635,7 +636,8 @@ public static float[] sample(float[] source, int k, float[] target, RandomGenera
    */
   public static <T> T[] sample(T[] source, int k, T[] target, RandomGenerator r) {
     SequenceSamplerUtils.validateK(k, source.length);
-    target = SequenceSamplerUtils.allocateIfNecessary(source, k, target);
+    target =
+        SequenceSamplerUtils.allocateIfNecessary(source.getClass().getComponentType(), k, target);
     System.arraycopy(source, 0, target, 0, k);
     for (int i = k; i < source.length; i++) {
       int j = RandomIndexer.nextInt(i + 1, r);

src/main/java/org/cicirello/sequences/SequenceSamplerUtils.java

@@ -1,6 +1,6 @@
 /*
  * JavaPermutationTools: A Java library for computation on permutations and sequences
- * Copyright 2005-2023 Vincent A. Cicirello, <https://www.cicirello.org/>.
+ * Copyright 2005-2026 Vincent A. Cicirello, <https://www.cicirello.org/>.
  *
  * This file is part of JavaPermutationTools (https://jpt.cicirello.org/).
  *
@@ -42,11 +42,9 @@ static void validateK(int k, int sourceLength) {
   }
 
   @SuppressWarnings("unchecked")
-  static <T> T[] allocateIfNecessary(T[] source, int k, T[] target) {
-    if (target == null) {
-      target = (T[]) Array.newInstance(source.getClass().getComponentType(), k);
-    } else if (target.length < k) {
-      target = (T[]) Array.newInstance(target.getClass().getComponentType(), k);
+  static <T> T[] allocateIfNecessary(Class<?> componentType, int k, T[] target) {
+    if (target == null || target.length < k) {
+      return (T[]) Array.newInstance(componentType, k);
     }
     return target;
   }