Add toImmutableBiMap to RichIterable.

Signed-off-by: Donald Raab <Donald.Raab@bnymellon.com>
eclipse · May 12, 2021 · 9ea7f6c · 9ea7f6c
1 parent 4372b31
commit 9ea7f6c
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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
@@ -31,6 +31,7 @@
 import org.eclipse.collections.api.bag.MutableBagIterable;
 import org.eclipse.collections.api.bag.sorted.ImmutableSortedBag;
 import org.eclipse.collections.api.bag.sorted.MutableSortedBag;
+import org.eclipse.collections.api.bimap.ImmutableBiMap;
 import org.eclipse.collections.api.bimap.MutableBiMap;
 import org.eclipse.collections.api.block.function.Function;
 import org.eclipse.collections.api.block.function.Function0;
@@ -1888,6 +1889,18 @@ default <NK, NV> ImmutableMap<NK, NV> toImmutableMap(
         return this.<NK, NV>toMap(keyFunction, valueFunction).toImmutable();
     }
 
+    /**
+     * Converts the collection to an immutable BiMap implementation using the specified key and value functions.
+     *
+     * @since 11.0
+     */
+    default <NK, NV> ImmutableBiMap<NK, NV> toImmutableBiMap(
+            Function<? super T, ? extends NK> keyFunction,
+            Function<? super T, ? extends NV> valueFunction)
+    {
+        return this.<NK, NV>toBiMap(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
@@ -1793,6 +1793,26 @@ public void toBiMap()
                 () -> integers.toBiMap(i -> "Constant Key", i -> "Constant Value"));
     }
 
+    @Test
+    public void toImmutableBiMap()
+    {
+        RichIterable<Integer> integers = this.newWith(1, 2, 3);
+
+        Assert.assertEquals(
+                Maps.mutable.with("1", "1", "2", "2", "3", "3"),
+                integers.toImmutableBiMap(Object::toString, Object::toString));
+
+        Assert.assertThrows(
+                IllegalArgumentException.class,
+                () -> integers.toImmutableBiMap(i -> "Constant Key", Objects::toString));
+        Assert.assertThrows(
+                IllegalArgumentException.class,
+                () -> integers.toImmutableBiMap(Object::toString, i -> "Constant Value"));
+        Assert.assertThrows(
+                IllegalArgumentException.class,
+                () -> integers.toImmutableBiMap(i -> "Constant Key", i -> "Constant Value"));
+    }
+
     @Test
     public void testToString()
     {