Add toImmutableMap to RichIterable.

Signed-off-by: Donald Raab <Donald.Raab@bnymellon.com>
eclipse · May 11, 2021 · 7572d68 · 7572d68
1 parent 43b9c67
commit 7572d68
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diff --git a/eclipse-collections-api/src/main/java/org/eclipse/collections/api/RichIterable.java b/eclipse-collections-api/src/main/java/org/eclipse/collections/api/RichIterable.java
@@ -67,6 +67,7 @@
 import org.eclipse.collections.api.factory.SortedSets;
 import org.eclipse.collections.api.list.ImmutableList;
 import org.eclipse.collections.api.list.MutableList;
+import org.eclipse.collections.api.map.ImmutableMap;
 import org.eclipse.collections.api.map.MapIterable;
 import org.eclipse.collections.api.map.MutableMap;
 import org.eclipse.collections.api.map.MutableMapIterable;
@@ -1875,6 +1876,18 @@ default <V extends Comparable<? super V>> ImmutableSortedBag<T> toImmutableSorte
         return this.toImmutableSortedBag(Comparator.comparing(function));
     }
 
+    /**
+     * Converts the collection to an ImmutableMap implementation using the specified key and value functions.
+     *
+     * @since 11.0
+     */
+    default <NK, NV> ImmutableMap<NK, NV> toImmutableMap(
+            Function<? super T, ? extends NK> keyFunction,
+            Function<? super T, ? extends NV> valueFunction)
+    {
+        return this.<NK, NV>toMap(keyFunction, valueFunction).toImmutable();
+    }
+
     /**
      * Returns a lazy (deferred) iterable, most likely implemented by calling LazyIterate.adapt(this).
      *

diff --git a/unit-tests/src/test/java/org/eclipse/collections/impl/AbstractRichIterableTestCase.java b/unit-tests/src/test/java/org/eclipse/collections/impl/AbstractRichIterableTestCase.java
@@ -75,6 +75,7 @@
 import org.eclipse.collections.api.factory.SortedBags;
 import org.eclipse.collections.api.list.ImmutableList;
 import org.eclipse.collections.api.list.MutableList;
+import org.eclipse.collections.api.map.ImmutableMap;
 import org.eclipse.collections.api.map.MapIterable;
 import org.eclipse.collections.api.map.MutableMap;
 import org.eclipse.collections.api.map.primitive.ObjectDoubleMap;
@@ -1715,6 +1716,19 @@ public void toMap()
         Assert.assertEquals(UnifiedMap.newWithKeysValues("1", "1", "2", "2", "3", "3", "4", "4"), map);
     }
 
+    @Test
+    public void toImmutableMap()
+    {
+        RichIterable<Integer> integers = this.newWith(1, 2, 3, 4);
+        ImmutableMap<String, String> map =
+                integers.toImmutableMap(Object::toString, Object::toString);
+        Assert.assertEquals(UnifiedMap.newWithKeysValues("1", "1", "2", "2", "3", "3", "4", "4"), map);
+        RichIterable<Integer> empty = this.newWith();
+        ImmutableMap<String, String> emptyMap =
+                empty.toImmutableMap(Object::toString, Object::toString);
+        Assert.assertSame(Maps.immutable.empty(), emptyMap);
+    }
+
     @Test
     public void toMapTarget()
     {