From 3db69a5eb075459af5eb7f81b81b0f60ee88e933 Mon Sep 17 00:00:00 2001
From: Filipe Sousa <natros@gmail.com>
Date: Sat, 11 Nov 2023 15:35:07 +0000
Subject: [PATCH] Add 'not' method to Predicate.

---
 .../emul/java/util/function/Predicate.java    |  5 ++
 .../google/gwt/emultest/EmulJava11Suite.java  |  2 +
 .../java11/util/function/PredicateTest.java   | 66 +++++++++++++++++++
 3 files changed, 73 insertions(+)
 create mode 100644 user/test/com/google/gwt/emultest/java11/util/function/PredicateTest.java

diff --git a/user/super/com/google/gwt/emul/java/util/function/Predicate.java b/user/super/com/google/gwt/emul/java/util/function/Predicate.java
index 6babe4f8783..b9ad769b307 100644
--- a/user/super/com/google/gwt/emul/java/util/function/Predicate.java
+++ b/user/super/com/google/gwt/emul/java/util/function/Predicate.java
@@ -47,4 +47,9 @@ default Predicate<T> or(Predicate<? super T> other) {
     checkCriticalNotNull(other);
     return t -> test(t) || other.test(t);
   }
+
+  @SuppressWarnings("unchecked")
+  static <T> Predicate<T> not(Predicate<? super T> other) {
+    return (Predicate<T>) other.negate();
+  }
 }
diff --git a/user/test/com/google/gwt/emultest/EmulJava11Suite.java b/user/test/com/google/gwt/emultest/EmulJava11Suite.java
index 18260e0714f..5e2ad3ab17e 100644
--- a/user/test/com/google/gwt/emultest/EmulJava11Suite.java
+++ b/user/test/com/google/gwt/emultest/EmulJava11Suite.java
@@ -19,6 +19,7 @@
 import com.google.gwt.emultest.java11.util.OptionalIntTest;
 import com.google.gwt.emultest.java11.util.OptionalLongTest;
 import com.google.gwt.emultest.java11.util.OptionalTest;
+import com.google.gwt.emultest.java11.util.function.PredicateTest;
 import org.junit.runner.RunWith;
 import org.junit.runners.Suite;
 
@@ -29,6 +30,7 @@
         OptionalIntTest.class,
         OptionalLongTest.class,
         OptionalTest.class,
+        PredicateTest.class,
 })
 public class EmulJava11Suite {
 }
diff --git a/user/test/com/google/gwt/emultest/java11/util/function/PredicateTest.java b/user/test/com/google/gwt/emultest/java11/util/function/PredicateTest.java
new file mode 100644
index 00000000000..e2bf74df739
--- /dev/null
+++ b/user/test/com/google/gwt/emultest/java11/util/function/PredicateTest.java
@@ -0,0 +1,66 @@
+/*
+ * Copyright 2023 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.google.gwt.emultest.java11.util.function;
+
+import com.google.gwt.emultest.java.util.EmulTestBase;
+import java.util.function.Predicate;
+
+/**
+ * A class that tests the functionality of the {@link Predicate} interface.
+ */
+public class PredicateTest extends EmulTestBase {
+  public void testIsEqual() {
+    Predicate<String> stringPredicate = Predicate.isEqual("test");
+    assertTrue(stringPredicate.test("test"));
+    assertFalse(stringPredicate.test("other string"));
+  }
+
+  public void testTest() {
+    Predicate<Integer> evenNumberPredicate = x -> x % 2 == 0;
+    assertTrue(evenNumberPredicate.test(2));
+    assertFalse(evenNumberPredicate.test(3));
+  }
+
+  public void testNegate() {
+    Predicate<Integer> evenNumberPredicate = x -> x % 2 == 0;
+    Predicate<Integer> notEvenPredicate = evenNumberPredicate.negate();
+    assertTrue(notEvenPredicate.test(3));
+    assertFalse(notEvenPredicate.test(2));
+  }
+
+  public void testAnd() {
+    Predicate<Integer> evenNumberPredicate = x -> x % 2 == 0;
+    Predicate<Integer> greaterThanFourPredicate = x -> x > 4;
+    Predicate<Integer> combinedPredicate = evenNumberPredicate.and(greaterThanFourPredicate);
+    assertTrue(combinedPredicate.test(6));
+    assertFalse(combinedPredicate.test(4));
+  }
+
+  public void testOr() {
+    Predicate<Integer> evenNumberPredicate = x -> x % 2 == 0;
+    Predicate<Integer> lessThanOrEqualToFourPredicate = x -> x <= 4;
+    Predicate<Integer> combinedPredicate = evenNumberPredicate.or(lessThanOrEqualToFourPredicate);
+    assertTrue(combinedPredicate.test(3));
+    assertFalse(combinedPredicate.test(5));
+  }
+
+  public void testNot() {
+    Predicate<Integer> evenNumberPredicate = x -> x % 2 == 0;
+    Predicate<Integer> notEvenPredicate = Predicate.not(evenNumberPredicate);
+    assertTrue(notEvenPredicate.test(3));
+    assertFalse(notEvenPredicate.test(2));
+  }
+}