Add emptyForBlank to StringHelpers. Closes lift#1127

core/util/src/main/scala/net/liftweb/util/StringHelpers.scala

@@ -364,11 +364,25 @@ trait StringHelpers {
   /** @return a SuperString with more available methods such as roboSplit or commafy */
   implicit def listStringToSuper(in: List[String]): SuperListString = new SuperListString(in)
 
+  @deprecated("Use blankForNull instead")
+  def emptyForNull(s: String) = blankForNull(s)
 
   /**
-   * Test for null and return either the given String if not null or the empty String.
+   * Test for null and return either the given String if not null or the blank String.
    */
-  def emptyForNull(s: String) = if (s != null) s else ""
+  def blankForNull(s: String) = if (s != null) s else ""
+
+  /**
+   * Turn a String into a Box[String], with Empty for the blank string.
+   *
+   * A string containing only spaces is considered blank.
+   *
+   * @return Full(s.trim) if s is not null or blank, Empty otherwise
+   */
+  def emptyForBlank(s: String) = blankForNull(s).trim match {
+    case "" => Empty
+    case s => Full(s)
+  }
 }
 
 /**

core/util/src/test/scala/net/liftweb/util/StringHelpersSpec.scala

@@ -306,12 +306,27 @@ object StringHelpersSpec extends Specification("StringHelpers Specification") wi
       (null: String).commafy must beNull
     }
   }
-  "The emptyForNull method" should {
+  "The blankForNull method" should {
     "return the empty String for a given null String" in {
-      StringHelpers.emptyForNull(null) must_== ""
+      StringHelpers.blankForNull(null) must_== ""
     }
     "return the given String for a given not-null String" in {
-      StringHelpers.emptyForNull("x") must_== "x"
+      StringHelpers.blankForNull("x") must_== "x"
+    }
+  }
+  "The emptyForBlank method" should {
+    import net.liftweb.common._
+    "return Empty for a given null String" in {
+      StringHelpers.emptyForBlank(null) must_== Empty
+    }
+    "return Empty for a given a blank String" in {
+      StringHelpers.emptyForBlank("") must_== Empty
+    }
+    "return Empty for a String of spaces" in {
+      StringHelpers.emptyForBlank("  ") must_== Empty
+    }
+    "return the trim'ed  String for a given not-null String" in {
+      StringHelpers.emptyForBlank(" x ") must_== Full("x")
     }
   }
 }