Add Strings.isNullOfEmpty(String) and Strings.emptyToNull(String), re #…

…70

src/main/java/org/libj/lang/Strings.java

@@ -52,6 +52,26 @@ private static String getRandom(final SecureRandom secureRandom, final int lengt
     return new String(array);
   }
 
+  /**
+   * Returns {@code true} if the given string is null or its length is {@code 0}, otherwise {@code false}.
+   *
+   * @param string The string to check.
+   * @return {@code true} if the string is null or its length is {@code 0}, otherwise {@code false}.
+   */
+  public static boolean isNullOrEmpty(final String string) {
+    return string == null || string.length() == 0;
+  }
+
+  /**
+   * Returns the given string if it is nonempty; otherwise {@code null}.
+   *
+   * @param string The string to test.
+   * @return The given string if it is nonempty; otherwise {@code null}.
+   */
+  public static String emptyToNull(final String string) {
+    return string == null || string.length() == 0 ? null : string;
+  }
+
   /**
    * Returns a randomly constructed alphanumeric string of the specified length.
    *

src/test/java/org/libj/lang/StringsTest.java

@@ -33,6 +33,20 @@ public class StringsTest {
 
   private static final Random r = new Random();
 
+  @Test
+  public void testIsNullOrEmpty() {
+    assertTrue(Strings.isNullOrEmpty(null));
+    assertTrue(Strings.isNullOrEmpty(""));
+    assertFalse(Strings.isNullOrEmpty(" "));
+  }
+
+  @Test
+  public void testEmptyToNull() {
+    assertNull(null);
+    assertNull(Strings.emptyToNull(""));
+    assertNotNull(Strings.emptyToNull(" "));
+  }
+
   @Test
   public void testIndexOf1() {
     for (int i = 0; i < 10000; ++i) { // [N]