avoid NPE in ListLevel.getNumberText() when numberText is null, see Bugzilla 50075

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1022456 13f79535-47bb-0310-9956-ffa450edef68

src/documentation/content/xdocs/status.xml

@@ -34,6 +34,7 @@
 
     <changes>
         <release version="3.7-beta4" date="2010-??-??">
+           <action dev="poi-developers" type="fix">50075 - avoid NPE in ListLevel.getNumberText() when numberText is null </action>
            <action dev="poi-developers" type="fix">50067 - marked commons-logging and log4j as optional dependencies in POI poms</action>
            <action dev="poi-developers" type="add">49928 - allow overridden built-in formats in XSSFCellStyle</action>
            <action dev="poi-developers" type="fix">49919 - support for BorderCode in HWPF</action>

src/scratchpad/src/org/apache/poi/hwpf/model/ListLevel.java

@@ -141,7 +141,10 @@ public final class ListLevel
 
   public String getNumberText()
   {
-    return new String(_numberText);
+    if (_numberText != null)
+      return new String(_numberText);
+    else
+      return null;
   }
 
   public void setStartAt(int startAt)

src/scratchpad/testcases/org/apache/poi/hwpf/usermodel/TestBug50075.java

@@ -0,0 +1,41 @@
+/* ====================================================================
+   Licensed to the Apache Software Foundation (ASF) under one or more
+   contributor license agreements.  See the NOTICE file distributed with
+   this work for additional information regarding copyright ownership.
+   The ASF licenses this file to You under the Apache License, Version 2.0
+   (the "License"); you may not use this file except in compliance with
+   the License.  You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+==================================================================== */
+package org.apache.poi.hwpf.usermodel;
+
+import org.apache.poi.hwpf.HWPFDocument;
+import org.apache.poi.hwpf.HWPFTestDataSamples;
+import org.apache.poi.hwpf.model.ListFormatOverride;
+import org.apache.poi.hwpf.model.ListLevel;
+
+import junit.framework.TestCase;
+
+public class TestBug50075 extends TestCase
+{
+
+  public void test() {
+    HWPFDocument doc = HWPFTestDataSamples.openSampleFile("Bug50075.doc");
+    Range range = doc.getRange();
+    assertEquals(1, range.numParagraphs());
+    ListEntry entry = (ListEntry) range.getParagraph(0);
+    ListFormatOverride override = doc.getListTables().getOverride(entry.getIlfo());
+    ListLevel level = doc.getListTables().getLevel(override.getLsid(), entry.getIlvl());
+    
+    // the bug reproduces, if this call fails with NullPointerException
+    level.getNumberText();
+  }
+  
+}