PDFBOX-6186: avoid NPE + test

git-svn-id: https://svn.apache.org/repos/asf/pdfbox/trunk@1932830 13f79535-47bb-0310-9956-ffa450edef68

Author: THausherr

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

@@ -238,6 +238,11 @@ public List<PDThread> getThreads()
      */
     public void setThreads(List<PDThread> threads)
     {
+        if (threads == null)
+        {
+            root.removeItem(COSName.THREADS);
+            return;
+        }
         COSArray threadsArray = new COSArray(threads);
         threadsArray.setDirect(false);
         root.setItem(COSName.THREADS, threadsArray);

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

@@ -685,6 +685,11 @@ public List<PDThreadBead> getThreadBeads()
      */
     public void setThreadBeads(List<PDThreadBead> beads)
     {
+        if (beads == null)
+        {
+            page.removeItem(COSName.B);
+            return;
+        }
         page.setItem(COSName.B, new COSArray(beads));
     }
 

pdfbox/src/test/java/org/apache/pdfbox/pdmodel/TestPDDocumentCatalog.java

@@ -18,6 +18,7 @@
 
 import java.io.IOException;
 import java.io.InputStream;
+import java.util.ArrayList;
 import java.util.List;
 
 import org.apache.pdfbox.Loader;
@@ -164,4 +165,19 @@ void handleBooleanInOpenAction() throws IOException
             assertNull(doc.getDocumentCatalog().getOpenAction());
         }
     }
+    
+    @Test
+    void testNullThreads() throws IOException
+    {
+        // PDFBOX-6186
+        try (PDDocument doc = new PDDocument())
+        {
+            PDDocumentCatalog documentCatalog = doc.getDocumentCatalog();
+            assertEquals(0, documentCatalog.getThreads().size());
+            documentCatalog.setThreads(new ArrayList<>());
+            assertEquals(0, documentCatalog.getThreads().size());
+            documentCatalog.setThreads(null);
+            assertEquals(0, documentCatalog.getThreads().size());
+        }
+   }
 }

pdfbox/src/test/java/org/apache/pdfbox/pdmodel/TestPDPage.java

@@ -18,23 +18,22 @@
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
+import java.util.ArrayList;
 
 import org.apache.pdfbox.pdmodel.common.PDRectangle;
 import org.apache.pdfbox.pdmodel.interactive.annotation.PDAnnotationWidget;
 import org.apache.pdfbox.pdmodel.interactive.form.PDAcroForm;
 import org.apache.pdfbox.pdmodel.interactive.form.PDTextField;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import org.junit.jupiter.api.Test;
 
-/**
- * Test case introduced with PDFBOX-6097
- * 
- */
 class TestPDPage
 {
     @Test
     void testAddingPageAfterCreatingAnnotation() throws IOException
     {
+        // PDFBOX-6097
         try (PDDocument document = new PDDocument())
         {
             PDPage page = new PDPage(PDRectangle.A4);
@@ -58,5 +57,19 @@ void testAddingPageAfterCreatingAnnotation() throws IOException
             document.close();
         }
     }
-
+    
+    @Test
+    void testNullThreadBeads() throws IOException
+    {
+        // PDFBOX-6186
+        try (PDDocument document = new PDDocument())
+        {
+            PDPage page = new PDPage();
+            assertEquals(0, page.getThreadBeads().size());
+            page.setThreadBeads(new ArrayList<>());
+            assertEquals(0, page.getThreadBeads().size());
+            page.setThreadBeads(null);
+            assertEquals(0, page.getThreadBeads().size());
+        }
+    }
 }