8171382: java.time.Duration missing isPositive method

Reviewed-by: rriggs, joehw, iris, bpb, scolebourne

src/java.base/share/classes/java/time/Duration.java

@@ -582,6 +582,20 @@ private static class DurationUnits {
     }
 
     //-----------------------------------------------------------------------
+    /**
+     * Checks if this duration is positive, excluding zero.
+     * <p>
+     * A {@code Duration} represents a directed distance between two points on
+     * the time-line and can therefore be positive, zero or negative.
+     * This method checks whether the length is greater than zero.
+     *
+     * @return true if this duration has a total length greater than zero
+     * @since 18
+     */
+    public boolean isPositive() {
+        return (seconds | nanos) > 0;
+    }
+
     /**
      * Checks if this duration is zero length.
      * <p>

test/jdk/java/time/tck/java/time/TCKDuration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2012, 2016, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2012, 2021, 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
@@ -908,16 +908,32 @@ public void test_isZero() {
         assertEquals(Duration.ofSeconds(-1, -1).isZero(), false);
     }
 
+    @Test
+    public void test_isPositive() {
+        assertEquals(Duration.ofNanos(0).isPositive(), false);
+        assertEquals(Duration.ofSeconds(0).isPositive(), false);
+        assertEquals(Duration.ofNanos(1).isPositive(), true);
+        assertEquals(Duration.ofSeconds(1).isPositive(), true);
+        assertEquals(Duration.ofSeconds(1, 1).isPositive(), true);
+        assertEquals(Duration.ofSeconds(Long.MAX_VALUE, 999_999_999).isPositive(), true);
+        assertEquals(Duration.ofNanos(-1).isPositive(), false);
+        assertEquals(Duration.ofSeconds(-1).isPositive(), false);
+        assertEquals(Duration.ofSeconds(-1, -1).isPositive(), false);
+        assertEquals(Duration.ofSeconds(Long.MIN_VALUE).isPositive(), false);
+    }
+
     @Test
     public void test_isNegative() {
         assertEquals(Duration.ofNanos(0).isNegative(), false);
         assertEquals(Duration.ofSeconds(0).isNegative(), false);
         assertEquals(Duration.ofNanos(1).isNegative(), false);
         assertEquals(Duration.ofSeconds(1).isNegative(), false);
         assertEquals(Duration.ofSeconds(1, 1).isNegative(), false);
+        assertEquals(Duration.ofSeconds(Long.MAX_VALUE, 999_999_999).isNegative(), false);
         assertEquals(Duration.ofNanos(-1).isNegative(), true);
         assertEquals(Duration.ofSeconds(-1).isNegative(), true);
         assertEquals(Duration.ofSeconds(-1, -1).isNegative(), true);
+        assertEquals(Duration.ofSeconds(Long.MIN_VALUE).isNegative(), true);
     }
 
     //-----------------------------------------------------------------------