/*
 * Copyright (c) 2003, 2014, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */

package javax.sql.rowset;

import java.sql.*;
import javax.sql.*;
import java.io.*;

import java.lang.reflect.*;

/**
 * Provides implementations for the methods that set and get
 * metadata information about a <code>RowSet</code> object's columns.
 * A <code>RowSetMetaDataImpl</code> object keeps track of the
 * number of columns in the rowset and maintains an internal array
 * of column attributes for each column.
 * <P>
 * A <code>RowSet</code> object creates a <code>RowSetMetaDataImpl</code>
 * object internally in order to set and retrieve information about
 * its columns.
 * <P>
 * NOTE: All metadata in a <code>RowSetMetaDataImpl</code> object
 * should be considered as unavailable until the <code>RowSet</code> object
 * that it describes is populated.
 * Therefore, any <code>RowSetMetaDataImpl</code> method that retrieves information
 * is defined as having unspecified behavior when it is called
 * before the <code>RowSet</code> object contains data.
 *
 * @since 1.5
 */
public class RowSetMetaDataImpl implements RowSetMetaData, Serializable {

 /**
 * The number of columns in the <code>RowSet</code> object that created
 * this <code>RowSetMetaDataImpl</code> object.
 * @serial
 */
 private int colCount;

 /**
 * An array of <code>ColInfo</code> objects used to store information
 * about each column in the <code>RowSet</code> object for which
 * this <code>RowSetMetaDataImpl</code> object was created. The first
 * <code>ColInfo</code> object in this array contains information about
 * the first column in the <code>RowSet</code> object, the second element
 * contains information about the second column, and so on.
 * @serial
 */
 private ColInfo[] colInfo;

 /**
 * Checks to see that the designated column is a valid column number for
 * the <code>RowSet</code> object for which this <code>RowSetMetaDataImpl</code>
 * was created. To be valid, a column number must be greater than
 * <code>0</code> and less than or equal to the number of columns in a row.
 * @throws <code>SQLException</code> with the message "Invalid column index"
 * if the given column number is out of the range of valid column
 * numbers for the <code>RowSet</code> object
 */
 private void checkColRange(int col) throws SQLException {
 if (col <= 0 || col > colCount) {
 throw new SQLException("Invalid column index :"+col);
 }
 }

 /**
 * Checks to see that the given SQL type is a valid column type and throws an
 * <code>SQLException</code> object if it is not.
 * To be valid, a SQL type must be one of the constant values
 * in the <code><a href="../../sql/Types.html">java.sql.Types</a></code>
 * class.
 *
 * @param SQLType an <code>int</code> defined in the class <code>java.sql.Types</code>
 * @throws SQLException if the given <code>int</code> is not a constant defined in the
 * class <code>java.sql.Types</code>
 */
 private void checkColType(int SQLType) throws SQLException {
 try {
 Class<?> c = java.sql.Types.class;
 Field[] publicFields = c.getFields();
 int fieldValue = 0;
 for (int i = 0; i < publicFields.length; i++) {
 fieldValue = publicFields[i].getInt(c);
 if (fieldValue == SQLType) {
 return;
 }
 }
 } catch (Exception e) {
 throw new SQLException(e.getMessage());
 }
 throw new SQLException("Invalid SQL type for column");
 }

 /**
 * Sets to the given number the number of columns in the <code>RowSet</code>
 * object for which this <code>RowSetMetaDataImpl</code> object was created.
 *
 * @param columnCount an <code>int</code> giving the number of columns in the
 * <code>RowSet</code> object
 * @throws SQLException if the given number is equal to or less than zero
 */
 public void setColumnCount(int columnCount) throws SQLException {

 if (columnCount <= 0) {
 throw new SQLException("Invalid column count. Cannot be less " +
 "or equal to zero");
 }

 colCount = columnCount;

 // If the colCount is Integer.MAX_VALUE,
 // we do not initialize the colInfo object.
 // even if we try to initialize the colCount with
 // colCount = Integer.MAx_VALUE-1, the colInfo
 // initialization fails throwing an ERROR
 // OutOfMemory Exception. So we do not initialize
 // colInfo at Integer.MAX_VALUE. This is to pass TCK.

 if(!(colCount == Integer.MAX_VALUE)) {
 colInfo = new ColInfo[colCount + 1];

 for (int i=1; i <= colCount; i++) {
 colInfo[i] = new ColInfo();
 }
 }


 }

 /**
 * Sets whether the designated column is automatically
 * numbered, thus read-only, to the given <code>boolean</code>
 * value.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns
 * in the rowset, inclusive
 * @param property <code>true</code> if the given column is
 * automatically incremented; <code>false</code>
 * otherwise
 * @throws SQLException if a database access error occurs or
 * the given index is out of bounds
 */
 public void setAutoIncrement(int columnIndex, boolean property) throws SQLException {
 checkColRange(columnIndex);
 colInfo[columnIndex].autoIncrement = property;
 }

 /**
 * Sets whether the name of the designated column is case sensitive to
 * the given <code>boolean</code>.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns
 * in the rowset, inclusive
 * @param property <code>true</code> to indicate that the column
 * name is case sensitive; <code>false</code> otherwise
 * @throws SQLException if a database access error occurs or
 * the given column number is out of bounds
 */
 public void setCaseSensitive(int columnIndex, boolean property) throws SQLException {
 checkColRange(columnIndex);
 colInfo[columnIndex].caseSensitive = property;
 }

 /**
 * Sets whether a value stored in the designated column can be used
 * in a <code>WHERE</code> clause to the given <code>boolean</code> value.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number
 * of columns in the rowset, inclusive
 * @param property <code>true</code> to indicate that a column
 * value can be used in a <code>WHERE</code> clause;
 * <code>false</code> otherwise
 *
 * @throws SQLException if a database access error occurs or
 * the given column number is out of bounds
 */
 public void setSearchable(int columnIndex, boolean property)
 throws SQLException {
 checkColRange(columnIndex);
 colInfo[columnIndex].searchable = property;
 }

 /**
 * Sets whether a value stored in the designated column is a cash
 * value to the given <code>boolean</code>.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns,
 * inclusive between <code>1</code> and the number of columns, inclusive
 * @param property true if the value is a cash value; false otherwise.
 * @throws SQLException if a database access error occurs
 * or the given column number is out of bounds
 */
 public void setCurrency(int columnIndex, boolean property)
 throws SQLException {
 checkColRange(columnIndex);
 colInfo[columnIndex].currency = property;
 }

 /**
 * Sets whether a value stored in the designated column can be set
 * to <code>NULL</code> to the given constant from the interface
 * <code>ResultSetMetaData</code>.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns, inclusive
 * @param property one of the following <code>ResultSetMetaData</code> constants:
 * <code>columnNoNulls</code>,
 * <code>columnNullable</code>, or
 * <code>columnNullableUnknown</code>
 *
 * @throws SQLException if a database access error occurs,
 * the given column number is out of bounds, or the value supplied
 * for the <i>property</i> parameter is not one of the following
 * constants:
 * <code>ResultSetMetaData.columnNoNulls</code>,
 * <code>ResultSetMetaData.columnNullable</code>, or
 * <code>ResultSetMetaData.columnNullableUnknown</code>
 */
 public void setNullable(int columnIndex, int property) throws SQLException {
 if ((property < ResultSetMetaData.columnNoNulls) ||
 property > ResultSetMetaData.columnNullableUnknown) {
 throw new SQLException("Invalid nullable constant set. Must be " +
 "either columnNoNulls, columnNullable or columnNullableUnknown");
 }
 checkColRange(columnIndex);
 colInfo[columnIndex].nullable = property;
 }

 /**
 * Sets whether a value stored in the designated column is a signed
 * number to the given <code>boolean</code>.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns, inclusive
 * @param property <code>true</code> to indicate that a column
 * value is a signed number;
 * <code>false</code> to indicate that it is not
 * @throws SQLException if a database access error occurs
 * or the given column number is out of bounds
 */
 public void setSigned(int columnIndex, boolean property) throws SQLException {
 checkColRange(columnIndex);
 colInfo[columnIndex].signed = property;
 }

 /**
 * Sets the normal maximum number of chars in the designated column
 * to the given number.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns, inclusive
 * @param size the maximum size of the column in chars; must be
 * <code>0</code> or more
 * @throws SQLException if a database access error occurs,
 * the given column number is out of bounds, or <i>size</i> is
 * less than <code>0</code>
 */
 public void setColumnDisplaySize(int columnIndex, int size) throws SQLException {
 if (size < 0) {
 throw new SQLException("Invalid column display size. Cannot be less " +
 "than zero");
 }
 checkColRange(columnIndex);
 colInfo[columnIndex].columnDisplaySize = size;
 }

 /**
 * Sets the suggested column label for use in printouts and
 * displays, if any, to <i>label</i>. If <i>label</i> is
 * <code>null</code>, the column label is set to an empty string
 * ("").
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns, inclusive
 * @param label the column label to be used in printouts and displays; if the
 * column label is <code>null</code>, an empty <code>String</code> is
 * set
 * @throws SQLException if a database access error occurs
 * or the given column index is out of bounds
 */
 public void setColumnLabel(int columnIndex, String label) throws SQLException {
 checkColRange(columnIndex);
 if (label != null) {
 colInfo[columnIndex].columnLabel = label;
 } else {
 colInfo[columnIndex].columnLabel = "";
 }
 }

 /**
 * Sets the column name of the designated column to the given name.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns, inclusive
 * @param columnName a <code>String</code> object indicating the column name;
 * if the given name is <code>null</code>, an empty <code>String</code>
 * is set
 * @throws SQLException if a database access error occurs or the given column
 * index is out of bounds
 */
 public void setColumnName(int columnIndex, String columnName) throws SQLException {
 checkColRange(columnIndex);
 if (columnName != null) {
 colInfo[columnIndex].columnName = columnName;
 } else {
 colInfo[columnIndex].columnName = "";
 }
 }

 /**
 * Sets the designated column's table's schema name, if any, to
 * <i>schemaName</i>. If <i>schemaName</i> is <code>null</code>,
 * the schema name is set to an empty string ("").
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns, inclusive
 * @param schemaName the schema name for the table from which a value in the
 * designated column was derived; may be an empty <code>String</code>
 * or <code>null</code>
 * @throws SQLException if a database access error occurs
 * or the given column number is out of bounds
 */
 public void setSchemaName(int columnIndex, String schemaName) throws SQLException {
 checkColRange(columnIndex);
 if (schemaName != null ) {
 colInfo[columnIndex].schemaName = schemaName;
 } else {
 colInfo[columnIndex].schemaName = "";
 }
 }

 /**
 * Sets the total number of decimal digits in a value stored in the
 * designated column to the given number.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns, inclusive
 * @param precision the total number of decimal digits; must be <code>0</code>
 * or more
 * @throws SQLException if a database access error occurs,
 * <i>columnIndex</i> is out of bounds, or <i>precision</i>
 * is less than <code>0</code>
 */
 public void setPrecision(int columnIndex, int precision) throws SQLException {

 if (precision < 0) {
 throw new SQLException("Invalid precision value. Cannot be less " +
 "than zero");
 }
 checkColRange(columnIndex);
 colInfo[columnIndex].colPrecision = precision;
 }

 /**
 * Sets the number of digits to the right of the decimal point in a value
 * stored in the designated column to the given number.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns, inclusive
 * @param scale the number of digits to the right of the decimal point; must be
 * zero or greater
 * @throws SQLException if a database access error occurs,
 * <i>columnIndex</i> is out of bounds, or <i>scale</i>
 * is less than <code>0</code>
 */
 public void setScale(int columnIndex, int scale) throws SQLException {
 if (scale < 0) {
 throw new SQLException("Invalid scale size. Cannot be less " +
 "than zero");
 }
 checkColRange(columnIndex);
 colInfo[columnIndex].colScale = scale;
 }

 /**
 * Sets the name of the table from which the designated column
 * was derived to the given table name.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns, inclusive
 * @param tableName the column's table name; may be <code>null</code> or an
 * empty string
 * @throws SQLException if a database access error occurs
 * or the given column number is out of bounds
 */
 public void setTableName(int columnIndex, String tableName) throws SQLException {
 checkColRange(columnIndex);
 if (tableName != null) {
 colInfo[columnIndex].tableName = tableName;
 } else {
 colInfo[columnIndex].tableName = "";
 }
 }

 /**
 * Sets the catalog name of the table from which the designated
 * column was derived to <i>catalogName</i>. If <i>catalogName</i>
 * is <code>null</code>, the catalog name is set to an empty string.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns, inclusive
 * @param catalogName the column's table's catalog name; if the catalogName
 * is <code>null</code>, an empty <code>String</code> is set
 * @throws SQLException if a database access error occurs
 * or the given column number is out of bounds
 */
 public void setCatalogName(int columnIndex, String catalogName) throws SQLException {
 checkColRange(columnIndex);
 if (catalogName != null)
 colInfo[columnIndex].catName = catalogName;
 else
 colInfo[columnIndex].catName = "";
 }

 /**
 * Sets the SQL type code for values stored in the designated column
 * to the given type code from the class <code>java.sql.Types</code>.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns, inclusive
 * @param SQLType the designated column's SQL type, which must be one of the
 * constants in the class <code>java.sql.Types</code>
 * @throws SQLException if a database access error occurs,
 * the given column number is out of bounds, or the column type
 * specified is not one of the constants in
 * <code>java.sql.Types</code>
 * @see java.sql.Types
 */
 public void setColumnType(int columnIndex, int SQLType) throws SQLException {
 // examine java.sql.Type reflectively, loop on the fields and check
 // this. Separate out into a private method
 checkColType(SQLType);
 checkColRange(columnIndex);
 colInfo[columnIndex].colType = SQLType;
 }

 /**
 * Sets the type name used by the data source for values stored in the
 * designated column to the given type name.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns, inclusive
 * @param typeName the data source-specific type name; if <i>typeName</i> is
 * <code>null</code>, an empty <code>String</code> is set
 * @throws SQLException if a database access error occurs
 * or the given column number is out of bounds
 */
 public void setColumnTypeName(int columnIndex, String typeName)
 throws SQLException {
 checkColRange(columnIndex);
 if (typeName != null) {
 colInfo[columnIndex].colTypeName = typeName;
 } else {
 colInfo[columnIndex].colTypeName = "";
 }
 }

 /**
 * Retrieves the number of columns in the <code>RowSet</code> object
 * for which this <code>RowSetMetaDataImpl</code> object was created.
 *
 * @return the number of columns
 * @throws SQLException if an error occurs determining the column count
 */
 public int getColumnCount() throws SQLException {
 return colCount;
 }

 /**
 * Retrieves whether a value stored in the designated column is
 * automatically numbered, and thus readonly.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns, inclusive
 * @return <code>true</code> if the column is automatically numbered;
 * <code>false</code> otherwise
 * @throws SQLException if a database access error occurs
 * or the given column number is out of bounds
 */
 public boolean isAutoIncrement(int columnIndex) throws SQLException {
 checkColRange(columnIndex);
 return colInfo[columnIndex].autoIncrement;
 }

 /**
 * Indicates whether the case of the designated column's name
 * matters.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns, inclusive
 * @return <code>true</code> if the column name is case sensitive;
 * <code>false</code> otherwise
 * @throws SQLException if a database access error occurs
 * or the given column number is out of bounds
 */
 public boolean isCaseSensitive(int columnIndex) throws SQLException {
 checkColRange(columnIndex);
 return colInfo[columnIndex].caseSensitive;
 }

 /**
 * Indicates whether a value stored in the designated column
 * can be used in a <code>WHERE</code> clause.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns, inclusive
 * @return <code>true</code> if a value in the designated column can be used in a
 * <code>WHERE</code> clause; <code>false</code> otherwise
 * @throws SQLException if a database access error occurs
 * or the given column number is out of bounds
 */
 public boolean isSearchable(int columnIndex) throws SQLException {
 checkColRange(columnIndex);
 return colInfo[columnIndex].searchable;
 }

 /**
 * Indicates whether a value stored in the designated column
 * is a cash value.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns, inclusive
 * @return <code>true</code> if a value in the designated column is a cash value;
 * <code>false</code> otherwise
 * @throws SQLException if a database access error occurs
 * or the given column number is out of bounds
 */
 public boolean isCurrency(int columnIndex) throws SQLException {
 checkColRange(columnIndex);
 return colInfo[columnIndex].currency;
 }

 /**
 * Retrieves a constant indicating whether it is possible
 * to store a <code>NULL</code> value in the designated column.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns, inclusive
 * @return a constant from the <code>ResultSetMetaData</code> interface;
 * either <code>columnNoNulls</code>,
 * <code>columnNullable</code>, or
 * <code>columnNullableUnknown</code>
 * @throws SQLException if a database access error occurs
 * or the given column number is out of bounds
 */
 public int isNullable(int columnIndex) throws SQLException {
 checkColRange(columnIndex);
 return colInfo[columnIndex].nullable;
 }

 /**
 * Indicates whether a value stored in the designated column is
 * a signed number.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns, inclusive
 * @return <code>true</code> if a value in the designated column is a signed
 * number; <code>false</code> otherwise
 * @throws SQLException if a database access error occurs
 * or the given column number is out of bounds
 */
 public boolean isSigned(int columnIndex) throws SQLException {
 checkColRange(columnIndex);
 return colInfo[columnIndex].signed;
 }

 /**
 * Retrieves the normal maximum width in chars of the designated column.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns, inclusive
 * @return the maximum number of chars that can be displayed in the designated
 * column
 * @throws SQLException if a database access error occurs
 * or the given column number is out of bounds
 */
 public int getColumnDisplaySize(int columnIndex) throws SQLException {
 checkColRange(columnIndex);
 return colInfo[columnIndex].columnDisplaySize;
 }

 /**
 * Retrieves the suggested column title for the designated
 * column for use in printouts and displays.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns, inclusive
 * @return the suggested column name to use in printouts and displays
 * @throws SQLException if a database access error occurs
 * or the given column number is out of bounds
 */
 public String getColumnLabel(int columnIndex) throws SQLException {
 checkColRange(columnIndex);
 return colInfo[columnIndex].columnLabel;
 }

 /**
 * Retrieves the name of the designated column.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns, inclusive
 * @return the column name of the designated column
 * @throws SQLException if a database access error occurs
 * or the given column number is out of bounds
 */
 public String getColumnName(int columnIndex) throws SQLException {
 checkColRange(columnIndex);
 return colInfo[columnIndex].columnName;
 }

 /**
 * Retrieves the schema name of the table from which the value
 * in the designated column was derived.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns,
 * inclusive
 * @return the schema name or an empty <code>String</code> if no schema
 * name is available
 * @throws SQLException if a database access error occurs
 * or the given column number is out of bounds
 */
 public String getSchemaName(int columnIndex) throws SQLException {
 checkColRange(columnIndex);
 String str ="";
 if(colInfo[columnIndex].schemaName == null){
 } else {
 str = colInfo[columnIndex].schemaName;
 }
 return str;
 }

 /**
 * Retrieves the total number of digits for values stored in
 * the designated column.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns, inclusive
 * @return the precision for values stored in the designated column
 * @throws SQLException if a database access error occurs
 * or the given column number is out of bounds
 */
 public int getPrecision(int columnIndex) throws SQLException {
 checkColRange(columnIndex);
 return colInfo[columnIndex].colPrecision;
 }

 /**
 * Retrieves the number of digits to the right of the decimal point
 * for values stored in the designated column.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns, inclusive
 * @return the scale for values stored in the designated column
 * @throws SQLException if a database access error occurs
 * or the given column number is out of bounds
 */
 public int getScale(int columnIndex) throws SQLException {
 checkColRange(columnIndex);
 return colInfo[columnIndex].colScale;
 }

 /**
 * Retrieves the name of the table from which the value
 * in the designated column was derived.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns, inclusive
 * @return the table name or an empty <code>String</code> if no table name
 * is available
 * @throws SQLException if a database access error occurs
 * or the given column number is out of bounds
 */
 public String getTableName(int columnIndex) throws SQLException {
 checkColRange(columnIndex);
 return colInfo[columnIndex].tableName;
 }

 /**
 * Retrieves the catalog name of the table from which the value
 * in the designated column was derived.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns, inclusive
 * @return the catalog name of the column's table or an empty
 * <code>String</code> if no catalog name is available
 * @throws SQLException if a database access error occurs
 * or the given column number is out of bounds
 */
 public String getCatalogName(int columnIndex) throws SQLException {
 checkColRange(columnIndex);
 String str ="";
 if(colInfo[columnIndex].catName == null){
 } else {
 str = colInfo[columnIndex].catName;
 }
 return str;
 }

 /**
 * Retrieves the type code (one of the <code>java.sql.Types</code>
 * constants) for the SQL type of the value stored in the
 * designated column.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns, inclusive
 * @return an <code>int</code> representing the SQL type of values
 * stored in the designated column
 * @throws SQLException if a database access error occurs
 * or the given column number is out of bounds
 * @see java.sql.Types
 */
 public int getColumnType(int columnIndex) throws SQLException {
 checkColRange(columnIndex);
 return colInfo[columnIndex].colType;
 }

 /**
 * Retrieves the DBMS-specific type name for values stored in the
 * designated column.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns, inclusive
 * @return the type name used by the data source
 * @throws SQLException if a database access error occurs
 * or the given column number is out of bounds
 */
 public String getColumnTypeName(int columnIndex) throws SQLException {
 checkColRange(columnIndex);
 return colInfo[columnIndex].colTypeName;
 }


 /**
 * Indicates whether the designated column is definitely
 * not writable, thus readonly.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns, inclusive
 * @return <code>true</code> if this <code>RowSet</code> object is read-Only
 * and thus not updatable; <code>false</code> otherwise
 * @throws SQLException if a database access error occurs
 * or the given column number is out of bounds
 */
 public boolean isReadOnly(int columnIndex) throws SQLException {
 checkColRange(columnIndex);
 return colInfo[columnIndex].readOnly;
 }

 /**
 * Indicates whether it is possible for a write operation on
 * the designated column to succeed. A return value of
 * <code>true</code> means that a write operation may or may
 * not succeed.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns, inclusive
 * @return <code>true</code> if a write operation on the designated column may
 * will succeed; <code>false</code> otherwise
 * @throws SQLException if a database access error occurs
 * or the given column number is out of bounds
 */
 public boolean isWritable(int columnIndex) throws SQLException {
 checkColRange(columnIndex);
 return colInfo[columnIndex].writable;
 }

 /**
 * Indicates whether a write operation on the designated column
 * will definitely succeed.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns, inclusive
 * @return <code>true</code> if a write operation on the designated column will
 * definitely succeed; <code>false</code> otherwise
 * @throws SQLException if a database access error occurs
 * or the given column number is out of bounds
 */
 public boolean isDefinitelyWritable(int columnIndex) throws SQLException {
 checkColRange(columnIndex);
 return true;
 }

 /**
 * Retrieves the fully-qualified name of the class in the Java
 * programming language to which a value in the designated column
 * will be mapped. For example, if the value is an <code>int</code>,
 * the class name returned by this method will be
 * <code>java.lang.Integer</code>.
 * <P>
 * If the value in the designated column has a custom mapping,
 * this method returns the name of the class that implements
 * <code>SQLData</code>. When the method <code>ResultSet.getObject</code>
 * is called to retrieve a value from the designated column, it will
 * create an instance of this class or one of its subclasses.
 *
 * @param columnIndex the first column is 1, the second is 2, and so on;
 * must be between <code>1</code> and the number of columns, inclusive
 * @return the fully-qualified name of the class in the Java programming
 * language that would be used by the method <code>RowSet.getObject</code> to
 * retrieve the value in the specified column. This is the class
 * name used for custom mapping when there is a custom mapping.
 * @throws SQLException if a database access error occurs
 * or the given column number is out of bounds
 */
 public String getColumnClassName(int columnIndex) throws SQLException {
 String className = String.class.getName();

 int sqlType = getColumnType(columnIndex);

 switch (sqlType) {

 case Types.NUMERIC:
 case Types.DECIMAL:
 className = java.math.BigDecimal.class.getName();
 break;

 case Types.BIT:
 className = java.lang.Boolean.class.getName();
 break;

 case Types.TINYINT:
 className = java.lang.Byte.class.getName();
 break;

 case Types.SMALLINT:
 className = java.lang.Short.class.getName();
 break;

 case Types.INTEGER:
 className = java.lang.Integer.class.getName();
 break;

 case Types.BIGINT:
 className = java.lang.Long.class.getName();
 break;

 case Types.REAL:
 className = java.lang.Float.class.getName();
 break;

 case Types.FLOAT:
 case Types.DOUBLE:
 className = java.lang.Double.class.getName();
 break;

 case Types.BINARY:
 case Types.VARBINARY:
 case Types.LONGVARBINARY:
 className = "byte[]";
 break;

 case Types.DATE:
 className = java.sql.Date.class.getName();
 break;

 case Types.TIME:
 className = java.sql.Time.class.getName();
 break;

 case Types.TIMESTAMP:
 className = java.sql.Timestamp.class.getName();
 break;

 case Types.BLOB:
 className = java.sql.Blob.class.getName();
 break;

 case Types.CLOB:
 className = java.sql.Clob.class.getName();
 break;
 }

 return className;
 }

 /**
 * Returns an object that implements the given interface to allow access to non-standard methods,
 * or standard methods not exposed by the proxy.
 * The result may be either the object found to implement the interface or a proxy for that object.
 * If the receiver implements the interface then that is the object. If the receiver is a wrapper
 * and the wrapped object implements the interface then that is the object. Otherwise the object is
 * the result of calling <code>unwrap</code> recursively on the wrapped object. If the receiver is not a
 * wrapper and does not implement the interface, then an <code>SQLException</code> is thrown.
 *
 * @param iface A Class defining an interface that the result must implement.
 * @return an object that implements the interface. May be a proxy for the actual implementing object.
 * @throws java.sql.SQLException If no object found that implements the interface
 * @since 1.6
 */
 public <T> T unwrap(java.lang.Class<T> iface) throws java.sql.SQLException {

 if(isWrapperFor(iface)) {
 return iface.cast(this);
 } else {
 throw new SQLException("unwrap failed for:"+ iface);
 }
 }

 /**
 * Returns true if this either implements the interface argument or is directly or indirectly a wrapper
 * for an object that does. Returns false otherwise. If this implements the interface then return true,
 * else if this is a wrapper then return the result of recursively calling <code>isWrapperFor</code> on the wrapped
 * object. If this does not implement the interface and is not a wrapper, return false.
 * This method should be implemented as a low-cost operation compared to <code>unwrap</code> so that
 * callers can use this method to avoid expensive <code>unwrap</code> calls that may fail. If this method
 * returns true then calling <code>unwrap</code> with the same argument should succeed.
 *
 * @param interfaces a Class defining an interface.
 * @return true if this implements the interface or directly or indirectly wraps an object that does.
 * @throws java.sql.SQLException if an error occurs while determining whether this is a wrapper
 * for an object with the given interface.
 * @since 1.6
 */
 public boolean isWrapperFor(Class<?> interfaces) throws SQLException {
 return interfaces.isInstance(this);
 }

 static final long serialVersionUID = 6893806403181801867L;

 private class ColInfo implements Serializable {
 /**
 * The field that indicates whether the value in this column is a number
 * that is incremented automatically, which makes the value read-only.
 * <code>true</code> means that the value in this column
 * is automatically numbered; <code>false</code> means that it is not.
 *
 * @serial
 */
 public boolean autoIncrement;

 /**
 * The field that indicates whether the value in this column is case sensitive.
 * <code>true</code> means that it is; <code>false</code> that it is not.
 *
 * @serial
 */
 public boolean caseSensitive;

 /**
 * The field that indicates whether the value in this column is a cash value
 * <code>true</code> means that it is; <code>false</code> that it is not.
 *
 * @serial
 */
 public boolean currency;

 /**
 * The field that indicates whether the value in this column is nullable.
 * The possible values are the <code>ResultSet</code> constants
 * <code>columnNoNulls</code>, <code>columnNullable</code>, and
 * <code>columnNullableUnknown</code>.
 *
 * @serial
 */
 public int nullable;

 /**
 * The field that indicates whether the value in this column is a signed number.
 * <code>true</code> means that it is; <code>false</code> that it is not.
 *
 * @serial
 */
 public boolean signed;

 /**
 * The field that indicates whether the value in this column can be used in
 * a <code>WHERE</code> clause.
 * <code>true</code> means that it can; <code>false</code> that it cannot.
 *
 * @serial
 */
 public boolean searchable;

 /**
 * The field that indicates the normal maximum width in characters for
 * this column.
 *
 * @serial
 */
 public int columnDisplaySize;

 /**
 * The field that holds the suggested column title for this column, to be
 * used in printing and displays.
 *
 * @serial
 */
 public String columnLabel;

 /**
 * The field that holds the name of this column.
 *
 * @serial
 */
 public String columnName;

 /**
 * The field that holds the schema name for the table from which this column
 * was derived.
 *
 * @serial
 */
 public String schemaName;

 /**
 * The field that holds the precision of the value in this column. For number
 * types, the precision is the total number of decimal digits; for character types,
 * it is the maximum number of characters; for binary types, it is the maximum
 * length in bytes.
 *
 * @serial
 */
 public int colPrecision;

 /**
 * The field that holds the scale (number of digits to the right of the decimal
 * point) of the value in this column.
 *
 * @serial
 */
 public int colScale;

 /**
 * The field that holds the name of the table from which this column
 * was derived. This value may be the empty string if there is no
 * table name, such as when this column is produced by a join.
 *
 * @serial
 */
 public String tableName ="";

 /**
 * The field that holds the catalog name for the table from which this column
 * was derived. If the DBMS does not support catalogs, the value may be the
 * empty string.
 *
 * @serial
 */
 public String catName;

 /**
 * The field that holds the type code from the class <code>java.sql.Types</code>
 * indicating the type of the value in this column.
 *
 * @serial
 */
 public int colType;

 /**
 * The field that holds the type name used by this particular data source
 * for the value stored in this column.
 *
 * @serial
 */
 public String colTypeName;

 /**
 * The field that holds the updatability boolean per column of a RowSet
 *
 * @serial
 */
 public boolean readOnly = false;

 /**
 * The field that hold the writable boolean per column of a RowSet
 *
 *@serial
 */
 public boolean writable = true;

 static final long serialVersionUID = 5490834817919311283L;
 }
}