Implement Optional.ifPresentOrElse.

PiperOrigin-RevId: 585727393
google · Nov 27, 2023 · 1f564eb · 1f564eb
1 parent cff83e5
commit 1f564eb
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diff --git a/jre/java/java/util/Optional.java b/jre/java/java/util/Optional.java
@@ -72,6 +72,14 @@ public void ifPresent(Consumer<? super T> consumer) {
     }
   }
 
+  public void ifPresentOrElse(Consumer<? super T> consumer, Runnable emptyConsumer) {
+    if (isPresent()) {
+      consumer.accept(ref);
+    } else {
+      emptyConsumer.run();
+    }
+  }
+
   public Optional<T> filter(Predicate<? super T> predicate) {
     checkNotNull(predicate);
     if (!isPresent() || predicate.test(ref)) {

diff --git a/jre/javatests/com/google/j2cl/jre/java8/util/OptionalTest.java b/jre/javatests/com/google/j2cl/jre/java8/util/OptionalTest.java
@@ -107,6 +107,38 @@ public void testIfPresent() {
     assertTrue("Consumer not executed", mutableFlag[0]);
   }
 
+  public void testIfPresentOrElse() {
+    if (isWasm()) {
+      // TODO(b/183769034): Re-enable when NPE on dereference is supported
+      return;
+    }
+
+    // empty case
+    empty.ifPresentOrElse(null, () -> {}); // should not fail as per JavaDoc
+    empty.ifPresentOrElse(wrapped -> fail("Empty Optional should not execute consumer"), () -> {});
+
+    // non-empty case
+    try {
+      present.ifPresentOrElse(null, () -> {});
+      fail("Non-Empty Optional must throw NullPointerException if consumer is null");
+    } catch (NullPointerException e) {
+      // expected
+    }
+
+    present.ifPresentOrElse(
+        (wrapped) -> {
+          assertSame(REFERENCE, wrapped);
+          mutableFlag[0] = true;
+        },
+        () -> fail("Non-Empty Optional should not call empty consumer"));
+    assertTrue("Consumer not executed", mutableFlag[0]);
+    mutableFlag[0] = false;
+    empty.ifPresentOrElse(
+        (wrapped) -> fail("Empty Optional should not call non-empty consumer"),
+        () -> mutableFlag[0] = true);
+    assertTrue("Consumer not executed", mutableFlag[0]);
+  }
+
   public void testFilter() {
     if (isWasm()) {
       // TODO(b/183769034): Re-enable when NPE on dereference is supported