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a Java JDBC driver for reading comma-separated-value files
/*
* CsvJdbc - a JDBC driver for CSV files
* Copyright (C) 2001 Jonathan Ackerman
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
package org.relique.jdbc.csv;
import java.io.IOException;
import java.sql.SQLException;
import java.util.Map;
import java.util.Vector;
import org.relique.io.DataReader;
public class CsvReader extends DataReader
{
private CsvRawReader rawReader;
private int transposedLines;
private int transposedFieldsToSkip;
private String[] columnNames;
private String[] tableAndColumnNames;
private String[] aliasedColumnNames;
private String[] columnTypes;
private String[] upperColumnNames;
private Vector firstTable;
private int joiningValueNo;
private int valuesToJoin;
private String[] joiningValues;
private StringConverter converter;
private String[] fieldValues;
private int lineNumber;
public CsvReader(CsvRawReader rawReader, int transposedLines,
int transposedFieldsToSkip, String headerline) throws SQLException
{
super();
this.rawReader = rawReader;
this.transposedLines = transposedLines;
this.transposedFieldsToSkip = transposedFieldsToSkip;
this.columnNames = rawReader.parseLine(headerline, true);
this.firstTable = null;
columnTypes = null;
if (!this.isPlainReader())
{
firstTable = new Vector();
joiningValueNo = 0;
joiningValues = null;
try
{
String[] values = null;
for (int i = 0; i < transposedLines; i++)
{
String line;
line = rawReader.getNextDataLine();
values = rawReader.parseLine(line, false);
firstTable.add(values);
}
valuesToJoin = values.length;
fieldValues = new String[columnNames.length];
}
catch (IOException e)
{
throw new SQLException(e.toString());
}
}
}
public void setConverter(StringConverter converter)
{
this.converter = converter;
}
private int getTransposedFieldsToSkip()
{
return transposedFieldsToSkip;
}
private boolean isPlainReader()
{
return transposedLines == 0 && transposedFieldsToSkip == 0;
}
@Override
public boolean next() throws SQLException
{
if (this.isPlainReader())
{
boolean result = rawReader.next();
lineNumber = rawReader.getLineNumber();
fieldValues = rawReader.getFieldValues();
return result;
}
else
{
if (joiningValues == null ||
joiningValueNo + getTransposedFieldsToSkip() == valuesToJoin)
{
String line;
try
{
line = rawReader.getNextDataLine();
if (line != null)
lineNumber = rawReader.getLineNumber();
}
catch (IOException e)
{
throw new SQLException(e.toString());
}
if (line == null)
return false;
joiningValues = rawReader.parseLine(line, false);
joiningValueNo = 0;
}
for (int i = 0; i < transposedLines; i++)
{
fieldValues[i] = firstTable.get(i)[joiningValueNo
+ getTransposedFieldsToSkip()];
}
for (int i = transposedLines; i < columnNames.length - 1; i++)
{
fieldValues[i] = joiningValues[i - transposedLines];
}
fieldValues[columnNames.length - 1] =
joiningValues[columnNames.length - transposedLines - 1 + joiningValueNo];
joiningValueNo++;
if (columnTypes == null)
getColumnTypes();
return true;
}
}
@Override
public String[] getColumnNames()
{
if (isPlainReader())
return rawReader.getColumnNames();
else
return columnNames;
}
private String[] getUpperColumnNames()
{
if (upperColumnNames == null)
{
String columnNames[] = getColumnNames();
upperColumnNames = new String[columnNames.length];
for (int i = 0; i < upperColumnNames.length; i++)
upperColumnNames[i] = columnNames[i].toUpperCase();
}
return upperColumnNames;
}
private String[] getTableAndColumnNames()
{
if (this.tableAndColumnNames == null)
{
String upperTableName = rawReader.getTableName().toUpperCase();
/*
* Create array of "tablename.columnname" column aliases that we can use for
* every row.
*/
String[] upperColumnNames = getUpperColumnNames();
this.tableAndColumnNames = new String[upperColumnNames.length];
for (int i = 0; i < upperColumnNames.length; i++)
{
this.tableAndColumnNames[i] = upperTableName + "." + upperColumnNames[i];
}
}
return this.tableAndColumnNames;
}
private String[] getAliasedColumnNames()
{
if (this.aliasedColumnNames == null)
{
String tableAlias = rawReader.getTableAlias();
if (tableAlias != null)
{
/*
* Create array of "T.ID" column aliases that we can use for
* every row.
*/
String[] upperColumnNames = getUpperColumnNames();
this.aliasedColumnNames = new String[upperColumnNames.length];
for (int i = 0; i < upperColumnNames.length; i++)
{
this.aliasedColumnNames[i] = tableAlias + "." + upperColumnNames[i];
}
}
}
return this.aliasedColumnNames;
}
private Object getField(int i) throws SQLException
{
if (isPlainReader())
return rawReader.getField(i);
else
return null;
}
@Override
public void close()
{
rawReader.close();
}
@Override
public Map getEnvironment() throws SQLException
{
if (fieldValues.length != getColumnNames().length)
{
throw new SQLException(CsvResources.getString("wrongColumnCount") + ": " +
lineNumber + " " +
CsvResources.getString("columnsRead") + ": " + fieldValues.length + " " +
CsvResources.getString("columnsExpected") + ": " + getColumnNames().length);
}
if (columnTypes == null)
getColumnTypes();
String[] columnNames = getUpperColumnNames();
String[] tableAndColumnNames = getTableAndColumnNames();
String[] columnAliases = getAliasedColumnNames();
int initialSize = columnNames.length * 2;
if (columnAliases != null)
initialSize += columnNames.length;
if (initialSize == 0)
initialSize = 1;
Map result = new MinimumMemoryMap(initialSize);
result.put(StringConverter.COLUMN_NAME, converter);
for (int i = 0; i < columnNames.length; i++)
{
String key = columnNames[i];
Object value = converter.convert(columnTypes[i], fieldValues[i]);
result.put(key, value);
result.put(tableAndColumnNames[i], value);
if (columnAliases != null)
{
/*
* Also allow column value to be accessed as S.ID if table alias
* S is set.
*/
result.put(columnAliases[i], value);
}
}
return result;
}
public void setColumnTypes(String line) throws SQLException
{
String[] typeNamesLoc = line.split(",");
if (typeNamesLoc.length == 0)
throw new SQLException(CsvResources.getString("invalidColumnType") + ": " + line);
columnTypes = new String[getColumnNames().length];
for (int i = 0; i < Math.min(typeNamesLoc.length, columnTypes.length); i++)
{
String typeName = typeNamesLoc[i].trim();
if (converter.forSQLName(typeName) == null)
throw new SQLException(CsvResources.getString("invalidColumnType") + ": " + typeName);
columnTypes[i] = typeName;
}
/*
* Use last column type for any remaining columns.
*/
for (int i = typeNamesLoc.length; i < columnTypes.length; i++)
{
columnTypes[i] = typeNamesLoc[typeNamesLoc.length - 1].trim();
}
}
@Override
public String[] getColumnTypes() throws SQLException
{
if (columnTypes == null)
{
inferColumnTypes();
}
return columnTypes;
}
private void inferColumnTypes() throws SQLException
{
if (fieldValues == null)
throw new SQLException(CsvResources.getString("cannotInferColumns"));
columnTypes = new String[fieldValues.length];
for (int i = 0; i < fieldValues.length; i++)
{
try
{
String typeName = "String";
String value = getField(i).toString();
if (value.equalsIgnoreCase("true") || value.equalsIgnoreCase("false"))
{
typeName = "Boolean";
}
else if (value.equals(("" + converter.parseInt(value))))
{
typeName = "Int";
}
else if (value.equals(("" + converter.parseLong(value))))
{
typeName = "Long";
}
else if (value.equals(("" + converter.parseDouble(value))))
{
typeName = "Double";
}
else if (value.equals(("" + converter.parseBytes(value))))
{
typeName = "Bytes";
}
else if (value.equals(("" + converter.parseBigDecimal(value))))
{
typeName = "BigDecimal";
}
else if (converter.parseTimestamp(value) != null)
{
typeName = "Timestamp";
}
else if (converter.parseDate(value) != null)
{
typeName = "Date";
}
else if (converter.parseTime(value) != null)
{
typeName = "Time";
}
else if (value.equals(("" + converter.parseAsciiStream(value))))
{
typeName = "AsciiStream";
}
columnTypes[i] = typeName;
}
catch (SQLException e)
{
}
}
}
@Override
public int[] getColumnSizes()
{
return rawReader.getColumnSizes();
}
@Override
public String getTableAlias()
{
return rawReader.getTableAlias();
}
}