diff --git a/src/fr/devinsy/util/FileTools.java b/src/fr/devinsy/util/FileTools.java
index c33c125..47b30cd 100644
--- a/src/fr/devinsy/util/FileTools.java
+++ b/src/fr/devinsy/util/FileTools.java
@@ -24,6 +24,45 @@ import java.net.URL;
  */
 public class FileTools
 {
+	/**
+	 * 
+	 * 
+	 * @param fileName
+	 *            Source.
+	 * 
+	 * @return Extension value or null.
+	 */
+	public static String addBeforeExtension(final String fileName, final String addition)
+	{
+		String result;
+
+		if (fileName == null)
+		{
+			result = null;
+		}
+		else if (addition == null)
+		{
+			result = fileName;
+		}
+		else
+		{
+			//
+			int separatorIndex = fileName.lastIndexOf('.');
+
+			//
+			if (separatorIndex > 0)
+			{
+				result = fileName.substring(0, separatorIndex) + addition + fileName.substring(separatorIndex);
+			}
+			else
+			{
+				result = fileName + addition;
+			}
+		}
+
+		//
+		return result;
+	}
 
 	/**
 	 * 
@@ -49,20 +88,7 @@ public class FileTools
 		{
 			//
 			String sourceFileName = file.getAbsolutePath();
-			int separatorIndex = sourceFileName.lastIndexOf('.');
-
-			//
-			String targetFileName;
-			if (separatorIndex > 0)
-			{
-				targetFileName = sourceFileName.substring(0, separatorIndex) + addition + sourceFileName.substring(separatorIndex);
-			}
-			else
-			{
-				targetFileName = sourceFileName + addition;
-			}
-
-			//
+			String targetFileName = addBeforeExtension(sourceFileName, addition);
 			result = new File(targetFileName);
 		}