From 06edc8ac8cb720d6ddf0c2afd92fb33ec66b8811 Mon Sep 17 00:00:00 2001
From: Anna-Lena Nowicki <nowicki@zib.de>
Date: Fri, 20 Feb 2026 18:15:15 +0100
Subject: [PATCH] add check for empty element (literatur_isbn, literatur_gnd)
 to avoid creation of empty LIDO element

---
 src/lido-1.0.xsl | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/lido-1.0.xsl b/src/lido-1.0.xsl
index 2c16f7f..e0e914a 100644
--- a/src/lido-1.0.xsl
+++ b/src/lido-1.0.xsl
@@ -1446,17 +1446,21 @@
                                             </lido:objectWebResource>
                                           </xsl:for-each>
                                             <xsl:for-each select="../literatur_isbn">
+                                              <xsl:if test="string-length(.) != 0">
                                                 <lido:objectID>
                                                     <xsl:attribute name="lido:type">ISBN</xsl:attribute>
                                                     <xsl:value-of select="."/>
                                                 </lido:objectID>
+                                              </xsl:if>
                                             </xsl:for-each>
                                             <xsl:for-each select="../literatur_gnd">
+                                              <xsl:if test="string-length(.) != 0">
                                                 <lido:objectID>
                                                     <xsl:attribute name="lido:source">dnb</xsl:attribute>
                                                     <xsl:attribute name="lido:type">uri</xsl:attribute>
                                                     <xsl:value-of select="."/>
                                                 </lido:objectID>
+                                              </xsl:if>
                                             </xsl:for-each>
                                         </lido:object>
                                     </xsl:if>