From 505493d8895df421f2205fdf7d72006a592f7d17 Mon Sep 17 00:00:00 2001
From: Florian Schmaus <flo@geekplace.eu>
Date: Tue, 7 May 2019 10:18:55 +0200
Subject: [PATCH] Add XmlStringBuilder.optAttribute(String, Number)

---
 .../org/jivesoftware/smack/util/XmlStringBuilder.java    | 7 +++++++
 .../smackx/jingle_filetransfer/element/Range.java        | 9 ++-------
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/smack-core/src/main/java/org/jivesoftware/smack/util/XmlStringBuilder.java b/smack-core/src/main/java/org/jivesoftware/smack/util/XmlStringBuilder.java
index 92b1f6a33..e710f52e2 100644
--- a/smack-core/src/main/java/org/jivesoftware/smack/util/XmlStringBuilder.java
+++ b/smack-core/src/main/java/org/jivesoftware/smack/util/XmlStringBuilder.java
@@ -327,6 +327,13 @@ public class XmlStringBuilder implements Appendable, CharSequence, Element {
         return this;
     }
 
+    public XmlStringBuilder optAttribute(String name, Number number) {
+        if (number != null) {
+            attribute(name, number.toString());
+        }
+        return this;
+    }
+
     /**
      * Add the given attribute if {@code value => 0}.
      *
diff --git a/smack-experimental/src/main/java/org/jivesoftware/smackx/jingle_filetransfer/element/Range.java b/smack-experimental/src/main/java/org/jivesoftware/smackx/jingle_filetransfer/element/Range.java
index 71a418818..312aca703 100644
--- a/smack-experimental/src/main/java/org/jivesoftware/smackx/jingle_filetransfer/element/Range.java
+++ b/smack-experimental/src/main/java/org/jivesoftware/smackx/jingle_filetransfer/element/Range.java
@@ -103,13 +103,8 @@ public class Range implements NamedElement {
     public CharSequence toXML(org.jivesoftware.smack.packet.XmlEnvironment enclosingNamespace) {
         XmlStringBuilder sb =  new XmlStringBuilder(this);
 
-        // TODO: (Introduce and) use XmlStringBuilder.optXmlAttribute(name, Number).
-        if (offset != null) {
-            sb.attribute(ATTR_OFFSET, offset);
-        }
-        if (length != null) {
-            sb.attribute(ATTR_LENGTH, length);
-        }
+        sb.optAttribute(ATTR_OFFSET, offset);
+        sb.optAttribute(ATTR_LENGTH, length);
 
         if (hash != null) {
             sb.rightAngleBracket();