(jackrabbit-oak) branch trunk updated: OAK-11528 : added util method for replacing Guava's Iterables.transform in oak-commons module (#2117)

[da...@apache.org]

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daim pushed a commit to branch trunk
in repository https://gitbox.apache.org/repos/asf/jackrabbit-oak.git


The following commit(s) were added to refs/heads/trunk by this push:
     new 77b7999340 OAK-11528 : added util method for replacing Guava's Iterables.transform in oak-commons module (#2117)
77b7999340 is described below

commit 77b799934028af9349de31da66f6499560bbf930
Author: Rishabh Kumar <ri...@gmail.com>
AuthorDate: Wed Feb 26 14:54:58 2025 +0530

    OAK-11528 : added util method for replacing Guava's Iterables.transform in oak-commons module (#2117)
    
    Co-authored-by: Rishabh Kumar <di...@adobe.com>
---
 .../oak/commons/collections/IterableUtils.java     | 15 ++++++++
 .../oak/commons/collections/IterableUtilsTest.java | 44 ++++++++++++++++++++++
 2 files changed, 59 insertions(+)

diff --git a/oak-commons/src/main/java/org/apache/jackrabbit/oak/commons/collections/IterableUtils.java b/oak-commons/src/main/java/org/apache/jackrabbit/oak/commons/collections/IterableUtils.java
index 171dc3604c..9d20b68acb 100644
--- a/oak-commons/src/main/java/org/apache/jackrabbit/oak/commons/collections/IterableUtils.java
+++ b/oak-commons/src/main/java/org/apache/jackrabbit/oak/commons/collections/IterableUtils.java
@@ -30,6 +30,7 @@ import java.util.Iterator;
 import java.util.List;
 import java.util.NoSuchElementException;
 import java.util.Objects;
+import java.util.function.Function;
 import java.util.stream.Collectors;
 
 /**
@@ -288,4 +289,18 @@ public class IterableUtils {
     public static <E> Iterable<E> filter(final Iterable<?> itr, final Class<E> type) {
         return (Iterable<E>) StreamUtils.toStream(itr).filter(type::isInstance).collect(Collectors.toList());
     }
+
+    /**
+     * Transforms an Iterable by applying a given function to each element.
+     *
+     * @param <I> the type of input elements
+     * @param <O> the type of output elements
+     * @param iterable the iterable to transform, must not be null
+     * @param function the function to apply to each element, must not be null
+     * @return an iterable containing the transformed elements
+     * @throws NullPointerException if the iterable or function is null
+     */
+    public static <I, O> Iterable<O> transform(final Iterable<I> iterable, final Function<? super I, ? extends O> function) {
+        return org.apache.commons.collections4.IterableUtils.transformedIterable(iterable, function::apply);
+    }
 }
diff --git a/oak-commons/src/test/java/org/apache/jackrabbit/oak/commons/collections/IterableUtilsTest.java b/oak-commons/src/test/java/org/apache/jackrabbit/oak/commons/collections/IterableUtilsTest.java
index 3a741e7532..ab9208e754 100644
--- a/oak-commons/src/test/java/org/apache/jackrabbit/oak/commons/collections/IterableUtilsTest.java
+++ b/oak-commons/src/test/java/org/apache/jackrabbit/oak/commons/collections/IterableUtilsTest.java
@@ -27,6 +27,7 @@ import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 import java.util.NoSuchElementException;
+import java.util.function.Function;
 
 /**
  * Unit tests for the {@link IterableUtils} class.
@@ -492,4 +493,47 @@ public class IterableUtilsTest {
             IterableUtils.filter(iterable, (Class)null);
         });
     }
+
+    @Test
+    public void testTransformWithNonEmptyIterable() {
+        Iterable<Integer> iterable = Arrays.asList(1, 2, 3);
+        Function<Integer, String> function = Object::toString;
+        Iterable<String> transformed = IterableUtils.transform(iterable, function);
+        List<String> result = ListUtils.toList(transformed.iterator());
+        Assert.assertEquals(Arrays.asList("1", "2", "3"), result);
+    }
+
+    @Test
+    public void testTransformWithEmptyIterable() {
+        Iterable<Integer> iterable = Collections.emptyList();
+        Function<Integer, String> function = Object::toString;
+        Iterable<String> transformed = IterableUtils.transform(iterable, function);
+        List<String> result = ListUtils.toList(transformed.iterator());
+        Assert.assertTrue(result.isEmpty());
+    }
+
+    @Test
+    public void testTransformWithNullIterable() {
+        Function<Integer, String> function = Object::toString;
+        Assert.assertThrows(NullPointerException.class, () -> {
+            IterableUtils.transform(null, function);
+        });
+    }
+
+    @Test
+    public void testTransformWithNullFunction() {
+        Iterable<Integer> iterable = Arrays.asList(1, 2, 3);
+        Assert.assertThrows(NullPointerException.class, () -> {
+            IterableUtils.transform(iterable, null);
+        });
+    }
+
+    @Test
+    public void testTransformWithComplexFunction() {
+        Iterable<String> iterable = Arrays.asList("a", "bb", "ccc");
+        Function<String, Integer> function = String::length;
+        Iterable<Integer> transformed = IterableUtils.transform(iterable, function);
+        List<Integer> result = ListUtils.toList(transformed.iterator());
+        Assert.assertEquals(Arrays.asList(1, 2, 3), result);
+    }
 }