Re: svn commit: r881271 - /incubator/pivot/trunk/tutorials/src/org/apache/pivot/tutorials/lists/ListViews.java

[Greg Brown]

I believe the compiler is capable of optimizing this:
String s = "a" + "b" + "c";

but not necessarily this:

String s = "a";
s += "b";
s += "c";

So FindBugs may not have been wrong to suggest the change. However,  
one case was a test app and the other was a tutorial (where clarity is  
much more important than performance), so please revert this change.  
Thanks.

G

On Nov 17, 2009, at 8:23 AM, Noel Grandin wrote:


You're wasting your time and making the code less clear.

See here:
  http://c2.com/cgi/wiki?StringBuffer

This is why it is a bad idea to blindly follow the FindBugs report.


smart...@apache.org wrote:
Author: smartini
Date: Tue Nov 17 13:19:52 2009
New Revision: 881271

URL: http://svn.apache.org/viewvc?rev=881271&view=rev
Log:
string concatenation improvement (as suggested by FindBugs)

Modified:
   incubator/pivot/trunk/tutorials/src/org/apache/pivot/tutorials/ 
lists/ListViews.java

Modified: incubator/pivot/trunk/tutorials/src/org/apache/pivot/ 
tutorials/lists/ListViews.java
URL: 
http://svn.apache.org/viewvc/incubator/pivot/trunk/tutorials/src/org/apache/pivot/tutorials/lists/ListViews.java?rev=881271&r1=881270&r2=881271&view=diff
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=====================================================================
--- incubator/pivot/trunk/tutorials/src/org/apache/pivot/tutorials/ 
lists/ListViews.java (original)
+++ incubator/pivot/trunk/tutorials/src/org/apache/pivot/tutorials/ 
lists/ListViews.java Tue Nov 17 13:19:52 2009
@@ -51,7 +51,7 @@
        }

        private void updateSelection(ListView listView) {
-            String selectionText = "";
+            StringBuffer selectionText = new StringBuffer("");

            Sequence<Span> selectedRanges =  
listView.getSelectedRanges();
            for (int i = 0, n = selectedRanges.getLength(); i < n; i 
++) {
@@ -61,15 +61,15 @@
                    j <= selectedRange.end;
                    j++) {
                    if (selectionText.length() > 0) {
-                        selectionText += ", ";
+                        selectionText.append(", ");
                    }

                    String text = (String)listView.getListData().get 
(j);
-                    selectionText += text;
+                    selectionText.append(text);
                }
            }

-            selectionLabel.setText(selectionText);
+            selectionLabel.setText(selectionText.toString());
        }
    };