PDFBOX-4892: avoid NPE, as suggested by valerybokov

git-svn-id: https://svn.apache.org/repos/asf/pdfbox/trunk@1891934 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/xmpbox/src/main/java/org/apache/xmpbox/xml/DomXmpParser.java b/xmpbox/src/main/java/org/apache/xmpbox/xml/DomXmpParser.java
index 58f9a43..2ac48a7 100644
--- a/xmpbox/src/main/java/org/apache/xmpbox/xml/DomXmpParser.java
+++ b/xmpbox/src/main/java/org/apache/xmpbox/xml/DomXmpParser.java
@@ -380,6 +380,11 @@
         if (DomHelper.isParseTypeResource(property))

         {

             AbstractStructuredType ast = parseLiDescription(xmp, DomHelper.getQName(property), property);

+            if (ast == null)

+            {

+                throw new XmpParsingException(ErrorType.Format, "property should contain child elements : "

+                        + property);

+            }

             ast.setPrefix(prefix);

             container.addProperty(ast);

         }

@@ -392,6 +397,11 @@
                         + property);

             }

             AbstractStructuredType ast = parseLiDescription(xmp, DomHelper.getQName(property), inner);

+            if (ast == null)

+            {

+                throw new XmpParsingException(ErrorType.Format, "inner element should contain child elements : "

+                        + inner);

+            }

             ast.setPrefix(prefix);

             container.addProperty(ast);

         }

@@ -416,6 +426,11 @@
             {

                 nsFinder.push(inner);

                 AbstractStructuredType ast = parseLiDescription(xmp, DomHelper.getQName(property), inner);

+                if (ast == null)

+                {

+                    throw new XmpParsingException(ErrorType.Format, "inner element should contain child elements : "

+                            + inner);

+                }

                 ast.setPrefix(prefix);

                 container.addProperty(ast);

             }