PDFBOX-6025: null is allowed

git-svn-id: https://svn.apache.org/repos/asf/pdfbox/trunk@1926700 13f79535-47bb-0310-9956-ffa450edef68

Author: THausherr

pdfbox/src/main/java/org/apache/pdfbox/pdmodel/PDEmbeddedFilesNameTreeNode.java

@@ -49,7 +49,7 @@ public PDEmbeddedFilesNameTreeNode( COSDictionary dic )
     @Override
     protected PDComplexFileSpecification convertCOSToPD( COSBase base ) throws IOException
     {
-        if (!(base instanceof COSDictionary))
+        if (base != null && !(base instanceof COSDictionary))
         {
             throw new IOException("dictionary expected here, but got " + base);
         }

pdfbox/src/main/java/org/apache/pdfbox/pdmodel/PDStructureElementNameTreeNode.java

@@ -51,7 +51,7 @@ public PDStructureElementNameTreeNode( COSDictionary dic )
     @Override
     protected PDStructureElement convertCOSToPD( COSBase base ) throws IOException
     {
-        if (!(base instanceof COSDictionary))
+        if (base != null && !(base instanceof COSDictionary))
         {
             throw new IOException("dictionary expected here, but got " + base);
         }

pdfbox/src/test/java/org/apache/pdfbox/pdmodel/common/PDIntegerNameTreeNode.java

@@ -49,7 +49,7 @@ public PDIntegerNameTreeNode(COSDictionary dic)
     @Override
     protected COSInteger convertCOSToPD(COSBase base) throws IOException
     {
-        if (!(base instanceof COSInteger))
+        if (base != null && !(base instanceof COSInteger))
         {
             throw new IOException("integer expected here, but got " + base);
         }