8184693: add Pattern.isEmpty

Added method Pattern.isEmpty

Reviewed-by: forax, chegar, smarks, psandoz, rriggs

src/java.base/share/classes/java/util/Optional.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012, 2017, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012, 2018, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -159,6 +159,17 @@ public final class Optional<T> {
         return value != null;
     }
 
+    /**
+     * If a value is  not present, returns {@code true}, otherwise
+     * {@code false}.
+     *
+     * @return  {@code true} if a value is not present, otherwise {@code false}
+     * @since   11
+     */
+    public boolean isEmpty() {
+        return value == null;
+    }
+
     /**
      * If a value is present, performs the given action with the value,
      * otherwise does nothing.

src/java.base/share/classes/java/util/OptionalDouble.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012, 2017, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012, 2018, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -139,6 +139,17 @@ public final class OptionalDouble {
         return isPresent;
     }
 
+    /**
+     * If a value is not present, returns {@code true}, otherwise
+     * {@code false}.
+     *
+     * @return  {@code true} if a value is not present, otherwise {@code false}
+     * @since   11
+     */
+    public boolean isEmpty() {
+        return !isPresent;
+    }
+
     /**
      * If a value is present, performs the given action with the value,
      * otherwise does nothing.

src/java.base/share/classes/java/util/OptionalInt.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012, 2017, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012, 2018, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -139,6 +139,17 @@ public final class OptionalInt {
         return isPresent;
     }
 
+    /**
+     * If a value is not present, returns {@code true}, otherwise
+     * {@code false}.
+     *
+     * @return  {@code true} if a value is not present, otherwise {@code false}
+     * @since   11
+     */
+    public boolean isEmpty() {
+        return !isPresent;
+    }
+
     /**
      * If a value is present, performs the given action with the value,
      * otherwise does nothing.

src/java.base/share/classes/java/util/OptionalLong.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012, 2017, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012, 2018, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -139,6 +139,17 @@ public final class OptionalLong {
         return isPresent;
     }
 
+    /**
+     * If a value is not present, returns {@code true}, otherwise
+     * {@code false}.
+     *
+     * @return  {@code true} if a value is not present, otherwise {@code false}
+     * @since   11
+     */
+    public boolean isEmpty() {
+        return !isPresent;
+    }
+
     /**
      * If a value is present, performs the given action with the value,
      * otherwise does nothing.

test/jdk/java/util/Optional/Basic.java

@@ -52,6 +52,7 @@ public class Basic {
         assertFalse(empty.equals("unexpected"));
 
         assertFalse(empty.isPresent());
+        assertTrue(empty.isEmpty());
         assertEquals(empty.hashCode(), 0);
         assertEquals(empty.orElse("x"), "x");
         assertEquals(empty.orElseGet(() -> "y"), "y");
@@ -87,6 +88,7 @@ public class Basic {
         assertFalse(opt.equals("unexpected"));
 
         assertTrue(opt.isPresent());
+        assertFalse(opt.isEmpty());
         assertEquals(opt.hashCode(), expected.hashCode());
         assertEquals(opt.orElse("unexpected"), expected);
         assertEquals(opt.orElseGet(() -> "unexpected"), expected);

test/jdk/java/util/Optional/BasicDouble.java

@@ -51,6 +51,7 @@ public class BasicDouble {
         assertFalse(empty.equals("unexpected"));
 
         assertFalse(empty.isPresent());
+        assertTrue(empty.isEmpty());
         assertEquals(empty.hashCode(), 0);
         assertEquals(empty.orElse(UNEXPECTED), UNEXPECTED);
         assertEquals(empty.orElseGet(() -> UNEXPECTED), UNEXPECTED);
@@ -86,6 +87,7 @@ public class BasicDouble {
         assertFalse(opt.equals("unexpected"));
 
         assertTrue(opt.isPresent());
+        assertFalse(opt.isEmpty());
         assertEquals(opt.hashCode(), Double.hashCode(expected));
         assertEquals(opt.orElse(UNEXPECTED), expected);
         assertEquals(opt.orElseGet(() -> UNEXPECTED), expected);

test/jdk/java/util/Optional/BasicInt.java

@@ -52,6 +52,7 @@ public class BasicInt {
         assertFalse(empty.equals("unexpected"));
 
         assertFalse(empty.isPresent());
+        assertTrue(empty.isEmpty());
         assertEquals(empty.hashCode(), 0);
         assertEquals(empty.orElse(UNEXPECTED), UNEXPECTED);
         assertEquals(empty.orElseGet(() -> UNEXPECTED), UNEXPECTED);
@@ -87,6 +88,7 @@ public class BasicInt {
         assertFalse(opt.equals("unexpected"));
 
         assertTrue(opt.isPresent());
+        assertFalse(opt.isEmpty());
         assertEquals(opt.hashCode(), Integer.hashCode(expected));
         assertEquals(opt.orElse(UNEXPECTED), expected);
         assertEquals(opt.orElseGet(() -> UNEXPECTED), expected);

test/jdk/java/util/Optional/BasicLong.java

@@ -51,6 +51,7 @@ public class BasicLong {
         assertFalse(empty.equals("unexpected"));
 
         assertFalse(empty.isPresent());
+        assertTrue(empty.isEmpty());
         assertEquals(empty.hashCode(), 0);
         assertEquals(empty.orElse(UNEXPECTED), UNEXPECTED);
         assertEquals(empty.orElseGet(() -> UNEXPECTED), UNEXPECTED);
@@ -86,6 +87,7 @@ public class BasicLong {
         assertFalse(opt.equals("unexpected"));
 
         assertTrue(opt.isPresent());
+        assertFalse(opt.isEmpty());
         assertEquals(opt.hashCode(), Long.hashCode(expected));
         assertEquals(opt.orElse(UNEXPECTED), expected);
         assertEquals(opt.orElseGet(() -> UNEXPECTED), expected);