added HSSFName.isDeleted() to check if the name points to cell that no longer exists

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@657355 13f79535-47bb-0310-9956-ffa450edef68

src/documentation/content/xdocs/changes.xml

@@ -37,6 +37,7 @@
 
 		<!-- Don't forget to update status.xml too! -->
         <release version="3.1-beta2" date="2008-05-??">
+           <action dev="POI-DEVELOPERS" type="fix">24207 - added HSSFName.isDeleted() to check if the name points to cell that no longer exists</action>
            <action dev="POI-DEVELOPERS" type="fix">40414 - fixed selected/active sheet after removing sheet from workbook</action>
            <action dev="POI-DEVELOPERS" type="fix">44523 - fixed workbook sheet selection and focus</action>
            <action dev="POI-DEVELOPERS" type="fix">45000 - Fixed NPE in ListLevel when numberText is null</action>

src/documentation/content/xdocs/hssf/quick-guide.xml

@@ -1225,7 +1225,19 @@ Examples:
             // Do something with this corner cell
         }
     }
-            </source>
+          </source>
+          <p>
+            Note, when a cell is deleted, Excel does not delete the attached named range. 
+            As result, workbook can contain named ranges that point to cells that no longer exist.
+            You should check the validity of a reference before constructing AreaReference  
+          </p>
+          <source>
+    if(hssfName.isDeleted()){
+      //named range points to a deleted cell. 
+    } else {
+      AreaReference ref = new AreaReference(hssfName.getReference());
+    }
+          </source>
         </section>
         <anchor id="CellComments"/>
         <section><title>Cell Comments</title>

src/documentation/content/xdocs/status.xml

@@ -34,6 +34,7 @@
 	<!-- Don't forget to update changes.xml too! -->
     <changes>
         <release version="3.1-beta2" date="2008-05-??">
+           <action dev="POI-DEVELOPERS" type="fix">24207 - added HSSFName.isDeleted() to check if the name points to cell that no longer exists</action>
            <action dev="POI-DEVELOPERS" type="fix">40414 - fixed selected/active sheet after removing sheet from workbook</action>
            <action dev="POI-DEVELOPERS" type="fix">44523 - fixed workbook sheet selection and focus</action>
            <action dev="POI-DEVELOPERS" type="fix">45000 - Fixed NPE in ListLevel when numberText is null</action>

src/java/org/apache/poi/hssf/usermodel/HSSFName.java

@@ -139,4 +139,13 @@ public class HSSFName {
 
     }
 
+    /**
+     * Tests if this name points to a cell that no longer exists
+     *
+     * @return true if the name refers to a deleted cell, false otherwise
+     */
+    public boolean isDeleted(){
+        String ref = getReference();
+        return "#REF!".endsWith(ref);
+    }
 }

src/testcases/org/apache/poi/hssf/usermodel/TestNamedRange.java

@@ -533,4 +533,28 @@ public final class TestNamedRange extends TestCase {
 		String contents = c.getStringCellValue();
 		assertEquals("Contents of cell retrieved by its named reference", contents, cvalue);
 	}
+
+    public void testDeletedReference() throws Exception {
+        HSSFWorkbook wb = HSSFTestDataSamples.openSampleWorkbook("24207.xls");
+        assertEquals(2, wb.getNumberOfNames());
+
+        HSSFName name1 = wb.getNameAt(0);
+        assertEquals("a", name1.getNameName());
+        assertEquals("Sheet1!$A$1", name1.getReference());
+        AreaReference ref1 = new AreaReference(name1.getReference());
+        assertTrue("Successfully constructed first reference", true);
+
+        HSSFName name2 = wb.getNameAt(1);
+        assertEquals("b", name2.getNameName());
+        assertEquals("#REF!", name2.getReference());
+        assertTrue(name2.isDeleted());
+        try {
+            AreaReference ref2 = new AreaReference(name2.getReference());
+            fail("attempt to supply an invalid reference to AreaReference constructor results in exception");
+        } catch (Exception e){
+            ;
+        }
+
+    }
+
 }