various trivial nit-picking

core/src/main/java/hudson/Util.java

@@ -474,8 +474,7 @@ public class Util {
     }
 
     public static String nullify(String v) {
-        if(v!=null && v.length()==0)    v=null;
-        return v;
+        return fixEmpty(v);
     }
 
     public static String removeTrailingSlash(String s) {

core/src/main/java/hudson/model/AbstractItem.java

@@ -153,7 +153,7 @@ public abstract class AbstractItem extends Actionable implements Item, HttpDelet
     }
     
     public void setDisplayName(String displayName) throws IOException {
-        this.displayName = displayName;
+        this.displayName = Util.fixEmpty(displayName);
         save();
     }
              

core/src/main/java/hudson/model/Job.java

@@ -941,21 +941,6 @@ public abstract class Job<JobT extends Job<JobT, RunT>, RunT extends Run<JobT, R
         return null;
     }
 
-    /**
-     * Takes the displayName request parameter and sets it into the the
-     * displayName member variable. If the displayName request parameter is a 
-     * 0 length string, then set the displayName member variable to null.
-     * @param req
-     * @throws IOException
-     */
-    void setDisplayNameFromRequest(StaplerRequest req) throws IOException {
-        String displayName = req.getParameter("displayName");
-        // if displayName is an empty string, just make it null so that we 
-        // use the project name
-        displayName = Util.nullify(displayName);
-        setDisplayName(displayName);        
-    }
-    
     //
     //
     // actions
@@ -973,11 +958,11 @@ public abstract class Job<JobT extends Job<JobT, RunT>, RunT extends Run<JobT, R
 
         keepDependencies = req.getParameter("keepDependencies") != null;
 
-        setDisplayNameFromRequest(req);
-        
         try {
             JSONObject json = req.getSubmittedForm();
 
+            setDisplayName(json.optString("displayNameOrNull"));
+
             if (req.getParameter("logrotate") != null)
                 logRotator = LogRotator.DESCRIPTOR.newInstance(req,json.getJSONObject("logrotate"));
             else

core/src/main/resources/hudson/model/AbstractItem/configure-common.jelly

@@ -64,9 +64,8 @@ THE SOFTWARE.
       <p:config-blockWhenUpstreamBuilding />
       <p:config-blockWhenDownstreamBuilding />
       <st:include page="configure-advanced.jelly" optional="true" />
-      <f:entry title="${%Display Name}" help="/help/project-config/displayName.html">
-         <f:textbox name="displayName" value="${it.displayNameOrNull}" 
-            checkUrl="'${rootURL}/checkDisplayName?displayName='+escape(this.value)+'&amp;jobName=${it.name}'"/>
+      <f:entry title="${%Display Name}" field="displayNameOrNull">
+         <f:textbox checkUrl="'${rootURL}/checkDisplayName?displayName='+escape(this.value)+'&amp;jobName=${it.name}'"/>
       </f:entry>
       
     </f:advanced>

core/src/test/java/hudson/model/JobTest.java

@@ -15,13 +15,10 @@ public class JobTest {
     @Test
     public void testSetDisplayName() throws Exception {
        final String displayName = "testSetDisplayName";
-       // create a mock stapler request that returns a display name
-       StaplerRequest req = Mockito.mock(StaplerRequest.class);
-       Mockito.when(req.getParameter(DISPLAY_NAME_PARAMETER_NAME)).thenReturn(displayName);
-       
+
        StubJob j = new StubJob();      
        // call setDisplayNameFromRequest
-       j.setDisplayNameFromRequest(req);
+       j.setDisplayNameOrNull(displayName);
        
        // make sure the displayname has been set
        Assert.assertEquals(displayName, j.getDisplayName());
@@ -29,14 +26,10 @@ public class JobTest {
 
     @Test
     public void testSetDisplayNameZeroLength() throws Exception {
-        // create a mock stapler request that returns a ""
-        StaplerRequest req = Mockito.mock(StaplerRequest.class);
-        Mockito.when(req.getParameter(DISPLAY_NAME_PARAMETER_NAME)).thenReturn("");
-
-        StubJob j = new StubJob();       
+        StubJob j = new StubJob();
         // call setDisplayNameFromRequest
-        j.setDisplayNameFromRequest(req);
-       
+        j.setDisplayNameOrNull("");
+
         // make sure the getDisplayName returns the project name
         Assert.assertEquals(StubJob.DEFAULT_STUB_JOB_NAME, j.getDisplayName());
     }