From acb16f7348707f13228389bb05a6d1c899bb88b4 Mon Sep 17 00:00:00 2001
From: Henri Yandell <bayard@apache.org>
Date: Thu, 5 Nov 2009 07:25:54 +0000
Subject: [PATCH] =?UTF-8?q?Applying=20J=C3=B6rg=20Gottschling's=20patch=20?=
 =?UTF-8?q?from=20LANG-358=20with=20Thomas=20Menzel's=20naming=20from=20LA?=
 =?UTF-8?q?NG-550=20and=20some=20of=20his=20tests.=20This=20adds=20a=20fir?=
 =?UTF-8?q?stNonNull=20method=20to=20ObjectUtils.?=
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git-svn-id: https://svn.apache.org/repos/asf/commons/proper/lang/trunk@833016 13f79535-47bb-0310-9956-ffa450edef68
---
 .../org/apache/commons/lang/ObjectUtils.java  | 32 +++++++++++++++++++
 .../apache/commons/lang/ObjectUtilsTest.java  | 15 +++++++++
 2 files changed, 47 insertions(+)

diff --git a/src/java/org/apache/commons/lang/ObjectUtils.java b/src/java/org/apache/commons/lang/ObjectUtils.java
index 44d3a9ac7..2bdcb1c30 100644
--- a/src/java/org/apache/commons/lang/ObjectUtils.java
+++ b/src/java/org/apache/commons/lang/ObjectUtils.java
@@ -318,4 +318,36 @@ public class ObjectUtils {
         }
     }
 
+    /**
+     * <p>Returns the first passed value which is not <code>null</code> or
+     * <code>null</code> otherwise.</p>
+     * 
+     * <pre>
+     * ObjectUtils.firstNonNull(null, null)      = null
+     * ObjectUtils.firstNonNull(null, "")        = ""
+     * ObjectUtils.firstNonNull(null, null, "")  = ""
+     * ObjectUtils.firstNonNull(null, "zz")      = "zz"
+     * ObjectUtils.firstNonNull("abc", *)        = "abc"
+     * ObjectUtils.firstNonNull(null, "xyz", *)  = "xyz"
+     * ObjectUtils.firstNonNull(Boolean.TRUE, *) = Boolean.TRUE
+     * ObjectUtils.firstNonNull()                = null
+     * </pre>
+     *
+     * @param values  the values to test, may be <code>null</code> or empty
+     * 
+     * @return The first value from <code>values</code> which is not
+     *         <code>null</code> or <code>null</code> otherwise.
+     */
+    public static <T> T firstNonNull(T... values) {
+      // This is a trivial implementation. There may be faster ones.
+      // According to the JRE Libraries, overloading the method with fixed
+      // parameter sizes may be faster.
+      for (T val : values) {
+        if (val != null && val != ObjectUtils.NULL) {
+          return val;
+        }
+      }
+      return null;
+    }
+
 }
diff --git a/src/test/org/apache/commons/lang/ObjectUtilsTest.java b/src/test/org/apache/commons/lang/ObjectUtilsTest.java
index c92b819ce..20ec1450d 100644
--- a/src/test/org/apache/commons/lang/ObjectUtilsTest.java
+++ b/src/test/org/apache/commons/lang/ObjectUtilsTest.java
@@ -216,4 +216,19 @@ public class ObjectUtilsTest extends TestCase {
 
         assertNull( ObjectUtils.min((String)null, (String)null) );
     }
+
+    public void testFirstNonNull() {
+      assertEquals(null, ObjectUtils.firstNonNull(null, null));
+      assertEquals("", ObjectUtils.firstNonNull(null, ""));
+      assertEquals("123", ObjectUtils.firstNonNull(null, null, "123", "456"));
+      assertEquals("123", ObjectUtils.firstNonNull("123", null, "456", null));
+      assertEquals(null, ObjectUtils.firstNonNull());
+      assertSame(Boolean.TRUE, ObjectUtils.firstNonNull(Boolean.TRUE));
+      assertNull(ObjectUtils.firstNonNull());
+      assertNull(ObjectUtils.firstNonNull(null, null));
+      assertSame("123", ObjectUtils.firstNonNull(null, ObjectUtils.NULL, "123", "456"));
+      assertSame("456", ObjectUtils.firstNonNull(ObjectUtils.NULL, "456", "123", null));
+      assertNull(ObjectUtils.firstNonNull(null, null, ObjectUtils.NULL));
+    }
+
 }