excel driver probes cells belonging to columns in order to recognize their common value type; columns are nullable now

Author: HardworkingMarek

build.gradle

@@ -50,7 +50,7 @@ publishing {
         maven(MavenPublication) {
             groupId = 'de.inetsoftware'
             artifactId = 'exceljconnect'
-            version = '1.2'
+            version = '1.3'
             from components.java
             pom {
                 name = 'Excel driver for Java'

src/com/inet/excel/ExcelDatabaseMetaData.java

@@ -28,6 +28,7 @@
 import java.util.Objects;
 
 import com.inet.excel.parser.ExcelParser;
+import com.inet.excel.parser.ValueType;
 
 /** Implementation of {@link ResultSetMetaData} for {@link ExcelConnection}
  */
@@ -50,6 +51,48 @@ public ExcelDatabaseMetaData( ExcelParser parser ) {
         this.parser = parser;
     }
 
+    /** Returns constant value that identifies the generic SQL type matching specified {@link ValueType}.
+     * @param type type to return constant value for. Must not be null.
+     * @return constant value that identifies the generic SQL type matching specified {@link ValueType}.
+     */
+    static int getDataType( ValueType type ) {
+        switch( type ) {
+            case DATE:
+                return Types.DATE;
+            case NUMBER:
+                return Types.NUMERIC;
+            case TIME:
+                return Types.TIME;
+            case TIMESTAMP:
+                return Types.TIMESTAMP;
+            case VARCHAR:
+                return Types.VARCHAR;
+            default:
+                return Types.JAVA_OBJECT;
+        }
+    }
+
+    /** Returns name that identifies the generic SQL type matching specified {@link ValueType}.
+     * @param type type to return constant value for. Must not be null.
+     * @return name that identifies the generic SQL type matching specified {@link ValueType}.
+     */
+    static String getDataTypeName( ValueType type ) {
+        switch( type ) {
+            case DATE:
+                return "DATE";
+            case NUMBER:
+                return "NUMERIC";
+            case TIME:
+                return "TIME";
+            case TIMESTAMP:
+                return "TIMESTAMP";
+            case VARCHAR:
+                return "VARCHAR";
+            default:
+                return "JAVA_OBJECT";
+        }
+    }
+
     /**
      * {@inheritDoc}
      */
@@ -1094,8 +1137,11 @@ public ResultSet getProcedureColumns( String catalog, String schemaPattern, Stri
                     continue;
                 }
 
+                List<ValueType> columnTypes = parser.getColumnTypes( sheetName );
                 int colIndex = 0;
                 for( String colName : parser.getColumnNames( sheetName ) ) {
+                    ValueType valueType = columnTypes.get( colIndex );
+
                     colIndex++; // indexing starts with 1
 
                     List<Object> row = new ArrayList<>();
@@ -1104,20 +1150,20 @@ public ResultSet getProcedureColumns( String catalog, String schemaPattern, Stri
                     row.add( sheetName );
                     row.add( colName );
                     row.add( Integer.valueOf( DatabaseMetaData.procedureColumnResult ) );
-                    row.add( Integer.valueOf( Types.JAVA_OBJECT ) );
-                    row.add( "JAVA_OBJECT" );
+                    row.add( Integer.valueOf( getDataType( valueType ) ) );
+                    row.add( getDataTypeName( valueType ) );
                     row.add( Integer.valueOf( 0 ) );
                     row.add( Integer.valueOf( COLUMN_SIZE_IN_BYTES ) );
                     row.add( Integer.valueOf( COLUMN_SIZE_IN_BYTES ) );
                     row.add( null );
-                    row.add( Integer.valueOf( DatabaseMetaData.procedureNoNulls ) );
+                    row.add( Integer.valueOf( DatabaseMetaData.procedureNullable ) );
                     row.add( "" );
                     row.add( "" );
                     row.add( null );
                     row.add( null );
                     row.add( Integer.valueOf( COLUMN_SIZE_IN_BYTES ) );
                     row.add( Integer.valueOf( colIndex ) );
-                    row.add( "NO" );
+                    row.add( "YES" );
                     row.add( sheetName );
 
                     allRows.add( row );

src/com/inet/excel/ExcelDriver.java

@@ -35,7 +35,7 @@ public class ExcelDriver implements Driver {
     public static final String URL_PREFIX    = "jdbc:inetexcel:";
     public static final String DRIVER_NAME   = "inetexcel";
     public static final int    MAJOR_VERSION = 1;
-    public static final int    MINOR_VERSION = 2;
+    public static final int    MINOR_VERSION = 3;
 
     /** Throws exception indicating that requested operation is not supported.
      * @throws SQLException exception indicating that requested operation is not supported.

src/com/inet/excel/ExcelSheetResultSet.java

@@ -20,6 +20,7 @@
 import java.util.List;
 
 import com.inet.excel.parser.ExcelParser;
+import com.inet.excel.parser.ValueType;
 
 /** Class for result set used to retrieve data of the sheet from Excel document.
  */
@@ -50,7 +51,8 @@ public ExcelSheetResultSet( ExcelParser parser, String sheetName, int maxRowsPer
         this.parser = parser;
         this.sheetName = sheetName;
         this.maxRowsPerBatch = maxRowsPerBatch;
-        this.metaData = new ExcelSheetResultSetMetaData( parser.getFileName(), sheetName, getColumnNames() );
+        List<ValueType> columnTypes = parser.getColumnTypes( sheetName );
+        this.metaData = new ExcelSheetResultSetMetaData( parser.getFileName(), sheetName, getColumnNames(), columnTypes );
         this.rowCount = parser.getRowCount( sheetName );
         this.currentRowIndex = -1;
         this.currentBatchIndex = -1;

src/com/inet/excel/ExcelSheetResultSetMetaData.java

@@ -20,21 +20,25 @@
 import java.sql.Types;
 import java.util.List;
 
+import com.inet.excel.parser.ValueType;
+
 /** Implementation of {@link ResultSetMetaData} for {@link ExcelSheetResultSet}.
  */
 public class ExcelSheetResultSetMetaData implements ResultSetMetaData {
 
     private String fileName;
     private String sheetName;
     private List<String> columnNames;
+    private List<ValueType> columnTypes;
 
     /** Constructor of the class.
      * @param fileName file name of the Excel document.
      * @param sheetName name of the sheet from Excel document.
      * @param columnNames list of column names.
+     * @param columnTypes list of column types.
      * @throws IllegalArgumentException if any of given arguments is null.
      */
-    public ExcelSheetResultSetMetaData( String fileName, String sheetName, List<String> columnNames ) {
+    public ExcelSheetResultSetMetaData( String fileName, String sheetName, List<String> columnNames, List<ValueType> columnTypes ) {
         if( fileName == null ) {
             throw new IllegalArgumentException( "file name must not be null" );
         }
@@ -44,9 +48,13 @@ public ExcelSheetResultSetMetaData( String fileName, String sheetName, List<Stri
         if( columnNames == null ) {
             throw new IllegalArgumentException( "list of column names must not be null" );
         }
+        if( columnTypes == null ) {
+            throw new IllegalArgumentException( "list of column types must not be null" );
+        }
         this.fileName = fileName;
         this.sheetName = sheetName;
         this.columnNames = columnNames;
+        this.columnTypes = columnTypes;
     }
 
     /**
@@ -112,7 +120,7 @@ public boolean isCurrency( int column ) throws SQLException {
      */
     @Override
     public int isNullable( int column ) throws SQLException {
-        return columnNoNulls;
+        return columnNullable;
     }
 
     /**
@@ -192,15 +200,17 @@ public String getCatalogName( int column ) throws SQLException {
      */
     @Override
     public int getColumnType( int column ) throws SQLException {
-        return Types.JAVA_OBJECT;
+        ValueType valueType = columnTypes.get( column - 1 );
+        return ExcelDatabaseMetaData.getDataType( valueType );
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public String getColumnTypeName( int column ) throws SQLException {
-        return "JAVA_OBJECT";
+        ValueType valueType = columnTypes.get( column - 1 );
+        return ExcelDatabaseMetaData.getDataTypeName( valueType );
     }
 
     /**
@@ -232,6 +242,19 @@ public boolean isDefinitelyWritable( int column ) throws SQLException {
      */
     @Override
     public String getColumnClassName( int column ) throws SQLException {
-        return String.class.getName(); //TODO
+        ValueType valueType = columnTypes.get( column - 1 );
+        switch( valueType ) {
+            case DATE:
+                return java.util.Date.class.getName();
+            case NUMBER:
+                return Double.class.getName();
+            case TIME:
+                return java.sql.Time.class.getName();
+            case TIMESTAMP:
+                return java.sql.Timestamp.class.getName();
+            case VARCHAR:
+            default:
+                return String.class.getName();
+        }
     }
 }