44929 - Improved error handling in HSSFWorkbook when attempting to read a BIFF5 file

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@653117 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">44929 - Improved error handling in HSSFWorkbook when attempting to read a BIFF5 file</action>
            <action dev="POI-DEVELOPERS" type="fix">44675 - Parameter operand classes (function metadata) required to encode SUM() etc properly. Added parse validation for number of parameters</action>
            <action dev="POI-DEVELOPERS" type="fix">44921 - allow Ptg.writeBytes() to be called on relative ref Ptgs (RefN* and AreaN*)</action>
            <action dev="POI-DEVELOPERS" type="fix">44914 - Fix/suppress warning message "WARN. Unread n bytes of record 0xNN"</action>

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">44929 - Improved error handling in HSSFWorkbook when attempting to read a BIFF5 file</action>
            <action dev="POI-DEVELOPERS" type="fix">44675 - Parameter operand classes (function metadata) required to encode SUM() etc properly. Added parse validation for number of parameters</action>
            <action dev="POI-DEVELOPERS" type="fix">44921 - allow Ptg.writeBytes() to be called on relative ref Ptgs (RefN* and AreaN*)</action>
            <action dev="POI-DEVELOPERS" type="fix">44914 - Fix/suppress warning message "WARN. Unread n bytes of record 0xNN"</action>

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

@@ -168,6 +168,42 @@ public class HSSFWorkbook extends POIDocument
         this(fs.getRoot(), fs, preserveNodes);
     }
 
+    /**
+     * Normally, the Workbook will be in a POIFS Stream
+     * called "Workbook". However, some weird XLS generators use "WORKBOOK"
+     */
+    private static final String[] WORKBOOK_DIR_ENTRY_NAMES = {
+        "Workbook", // as per BIFF8 spec
+        "WORKBOOK",
+    };
+
+
+    private static String getWorkbookDirEntryName(DirectoryNode directory) {
+
+        String[] potentialNames = WORKBOOK_DIR_ENTRY_NAMES;
+        for (int i = 0; i < potentialNames.length; i++) {
+            String wbName = potentialNames[i];
+            try {
+                directory.getEntry(wbName);
+                return wbName;
+            } catch (FileNotFoundException e) {
+                // continue - to try other options
+            }
+        }
+
+        // check for previous version of file format
+        try {
+            directory.getEntry("Book");
+            throw new IllegalArgumentException("The supplied spreadsheet seems to be Excel 5.0/7.0 (BIFF5) format. "
+                    + "POI only supports BIFF8 format (from Excel versions 97/2000/XP/2003)");
+        } catch (FileNotFoundException e) {
+            // fall through
+        }
+
+        throw new IllegalArgumentException("The supplied POIFSFileSystem does not contain a BIFF8 'Workbook' entry. "
+            + "Is it really an excel file?");
+    }
+
     /**
      * given a POI POIFSFileSystem object, and a specific directory
      *  within it, read in its Workbook and populate the high and
@@ -186,6 +222,8 @@ public class HSSFWorkbook extends POIDocument
             throws IOException
     {
         super(directory, fs);
+        String workbookName = getWorkbookDirEntryName(directory);
+
         this.preserveNodes = preserveNodes;
 
         // If we're not preserving nodes, don't track the
@@ -198,27 +236,8 @@ public class HSSFWorkbook extends POIDocument
         sheets = new ArrayList(INITIAL_CAPACITY);
         names  = new ArrayList(INITIAL_CAPACITY);
 
-        // Normally, the Workbook will be in a POIFS Stream
-        //  called "Workbook". However, some wierd XLS generators
-        //  put theirs in one called "WORKBOOK"
-        String workbookName = "Workbook";
-        try {
-        	directory.getEntry(workbookName);
-        	// Is the default name
-        } catch(FileNotFoundException fe) {
-        	// Try the upper case form
-        	try {
-        		workbookName = "WORKBOOK";
-        		directory.getEntry(workbookName);
-        	} catch(FileNotFoundException wfe) {
-        		// Doesn't contain it in either form
-        		throw new IllegalArgumentException("The supplied POIFSFileSystem contained neither a 'Workbook' entry, nor a 'WORKBOOK' entry. Is it really an excel file?");
-        	}
-        }
-
-        
         // Grab the data from the workbook stream, however
-        //  it happens to be spelt.
+        //  it happens to be spelled.
         InputStream stream = directory.createDocumentInputStream(workbookName);
 
         EventRecordFactory factory = new EventRecordFactory();