bug 57840: check for null to avoid NPE; add unit test for XSSFWorkbook.getTable()

git-svn-id: https://svn.apache.org/repos/asf/poi/branches/xssf_structured_references@1747621 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -265,10 +265,15 @@ public final class HSSFEvaluationWorkbook implements FormulaRenderingWorkbook, E
         return extIx;
     }
 
+    @Override
     public SpreadsheetVersion getSpreadsheetVersion(){
         return SpreadsheetVersion.EXCEL97;
     }
 
+    /**
+      * @throws IllegalStateException: data tables are not supported in Excel 97-2003 format
+      */
+    @Override
     public Table getTable(String name) {
         throw new IllegalStateException("XSSF-style tables are not supported for HSSF");
     }

src/ooxml/java/org/apache/poi/xssf/usermodel/BaseXSSFEvaluationWorkbook.java

@@ -353,8 +353,11 @@ public abstract class BaseXSSFEvaluationWorkbook implements FormulaRenderingWork
      * @return The Data table in the workbook named <tt>name</tt>, or <tt>null</tt> if no table is named <tt>name</tt>.
      * @since 3.15 beta 2
      */
+    @Override
     public XSSFTable getTable(String name) {
-        return getTableCache().get(name.toLowerCase(Locale.ROOT));
+        if (name == null) return null;
+        String lname = name.toLowerCase(Locale.ROOT);
+        return getTableCache().get(lname);
     }
     
     public UDFFinder getUDFFinder(){

src/ooxml/java/org/apache/poi/xssf/usermodel/XSSFWorkbook.java

@@ -2271,7 +2271,7 @@ public class XSSFWorkbook extends POIXMLDocument implements Workbook {
      * @since 3.15 beta 2
      */
     public XSSFTable getTable(String name) {
-        if (sheets != null) {
+        if (name != null && sheets != null) {
             for (XSSFSheet sheet : sheets) {
                 for (XSSFTable tbl : sheet.getTables()) {
                     if (name.equalsIgnoreCase(tbl.getName())) {

src/ooxml/testcases/org/apache/poi/xssf/usermodel/TestXSSFSheet.java

@@ -1137,7 +1137,7 @@ public final class TestXSSFSheet extends BaseTestXSheet {
     }
 
     /**
-     * See bug #50829
+     * See bug #50829 test data tables
      */
     @Test
     public void tables() throws IOException {

src/ooxml/testcases/org/apache/poi/xssf/usermodel/TestXSSFWorkbook.java

@@ -1107,4 +1107,36 @@ public final class TestXSSFWorkbook extends BaseTestXWorkbook {
 			assertTrue("Had: " + e.getCause(), e.getCause() instanceof IOException);
 		}
 	}
+
+    /**
+     * See bug #57840 test data tables
+     */
+    @Test
+    public void getTable() throws IOException {
+       XSSFWorkbook wb = XSSFTestDataSamples.openSampleWorkbook("WithTable.xlsx");
+       XSSFTable table1 = wb.getTable("Tabella1");
+       assertNotNull("Tabella1 was not found in workbook", table1);
+       assertEquals("Table name", "Tabella1", table1.getName());
+       assertEquals("Sheet name", "Foglio1", table1.getSheetName());
+
+       // Table lookup should be case-insensitive
+       assertSame("Case insensitive table name lookup", table1, wb.getTable("TABELLA1"));
+
+       // If workbook does not contain any data tables matching the provided name, getTable should return null
+       assertNull("Null table name should not throw NPE", wb.getTable(null));
+       assertNull("Should not be able to find non-existent table", wb.getTable("Foglio1"));
+
+       // If a table is added after getTable is called it should still be reachable by XSSFWorkbook.getTable
+       // This test makes sure that if any caching is done that getTable never uses a stale cache
+       XSSFTable table2 = wb.getSheet("Foglio2").createTable();
+       table2.setName("Table2");
+       assertSame("Did not find Table2", table2, wb.getTable("Table2"));
+       
+       // If table name is modified after getTable is called, the table can only be found by its new name
+       // This test makes sure that if any caching is done that getTable never uses a stale cache
+       table1.setName("Table1");
+       assertSame("Did not find Tabella1 renamed to Table1", table1, wb.getTable("TABLE1"));
+
+       wb.close();
+    }
 }