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a Java JDBC driver for reading comma-separated-value files
/*
* CsvJdbc - a JDBC driver for CSV files
* Copyright (C) 2011 Mario Frasca
* 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.dbf;
import java.io.File;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.sql.SQLException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.relique.io.DataReader;
import org.relique.jdbc.csv.CsvResources;
import org.relique.jdbc.csv.MinimumMemoryMap;
public class DbfReader extends DataReader
{
private Object table = null;
private List fields;
private Integer recordCount;
private Object record;
private int rowNo;
private Class fieldClass;
private Class recordClass;
private Class tableClass;
private Method tableOpenMethod;
private Method tableGetFieldsMethod;
private Method tableCloseMethod;
private Method fieldGetNameMethod;
private Method tableGetRecordCountMethod;
private Method tableGetRecordAtMethod;
private Method recordGetTypedValueMethod;
private Method fieldGetTypeMethod;
private Method fieldGetLengthMethod;
private Map dbfTypeToSQLType;
private String upperTableName;
private String tableAlias;
private String[] columnNames = null;
public DbfReader(String path, String tableName, String tableAlias, String charset) throws SQLException
{
super();
try
{
fieldClass = Class.forName("nl.knaw.dans.common.dbflib.Field");
recordClass = Class.forName("nl.knaw.dans.common.dbflib.Record");
tableClass = Class.forName("nl.knaw.dans.common.dbflib.Table");
}
catch (ClassNotFoundException e)
{
throw new DbfClassNotFoundException(CsvResources.getString("noDansDbf") + ": " + e);
}
try
{
tableOpenMethod = tableClass.getMethod("open");
tableCloseMethod = tableClass.getMethod("close");
tableGetFieldsMethod = tableClass.getMethod("getFields");
fieldGetNameMethod = fieldClass.getMethod("getName");
tableGetRecordCountMethod = tableClass.getMethod("getRecordCount");
tableGetRecordAtMethod = tableClass.getMethod("getRecordAt", Integer.TYPE);
recordGetTypedValueMethod = recordClass.getMethod("getTypedValue", String.class);
fieldGetTypeMethod = fieldClass.getMethod("getType");
fieldGetLengthMethod = fieldClass.getMethod("getLength");
}
catch (Exception e)
{
throw new SQLException(CsvResources.getString("dansDbfError") + ": " + e);
}
try
{
Constructor tableConstructor;
if (charset != null)
{
tableConstructor = tableClass.getConstructor(File.class, String.class);
table = tableConstructor.newInstance(new File(path), charset);
}
else
{
tableConstructor = tableClass.getConstructor(File.class);
table = tableConstructor.newInstance(new File(path));
}
tableOpenMethod.invoke(table);
fields = (List) tableGetFieldsMethod.invoke(table, new Object[] {});
recordCount = (Integer)tableGetRecordCountMethod.invoke(table, new Object[] {});
record = null;
rowNo = -1;
this.upperTableName = tableName.toUpperCase();
this.tableAlias = tableAlias;
}
catch (Exception e)
{
throw new SQLException(CsvResources.getString("dansDbfError") + ": " + e);
}
dbfTypeToSQLType = new HashMap<>();
dbfTypeToSQLType.put("CHARACTER", "String");
dbfTypeToSQLType.put("NUMBER", "Double");
dbfTypeToSQLType.put("LOGICAL", "Boolean");
dbfTypeToSQLType.put("DATE", "Date");
dbfTypeToSQLType.put("MEMO", "String");
dbfTypeToSQLType.put("FLOAT", "Double");
}
@Override
public void close() throws SQLException
{
if (table != null)
{
try
{
tableCloseMethod.invoke(table);
}
catch (Exception e)
{
throw new SQLException(CsvResources.getString("dansDbfError") + ": " + e);
}
}
table = null;
}
@Override
public String[] getColumnNames() throws SQLException
{
if (columnNames == null)
{
int columnCount = fields.size();
String[] result = new String[columnCount];
for (int i = 0; i < columnCount; i++)
{
Object field = fields.get(i);
try
{
result[i] = (String) fieldGetNameMethod.invoke(field, new Object[] {});
}
catch (Exception e)
{
throw new SQLException(CsvResources.getString("dansDbfError") + ": " + e);
}
}
columnNames = result;
}
return columnNames;
}
private Object getField(int i) throws SQLException
{
try
{
String []fieldNames = getColumnNames();
String fieldName = fieldNames[i];
Object result = recordGetTypedValueMethod.invoke(record, fieldName);
if(result instanceof String)
result = ((String) result).trim();
else if (result instanceof java.util.Date)
result = new java.sql.Date(((java.util.Date)result).getTime());
return result;
}
catch (Exception e)
{
throw new SQLException(CsvResources.getString("dansDbfError") + ": " + e);
}
}
@Override
public boolean next() throws SQLException
{
rowNo++;
if (rowNo >= recordCount.intValue())
return false;
try
{
record = tableGetRecordAtMethod.invoke(table, Integer.valueOf(rowNo));
}
catch (InvocationTargetException e)
{
/*
* Re-throw the exception from inside the dans library.
*/
throw new SQLException(e.getCause());
}
catch (Exception e)
{
return false;
}
return true;
}
@Override
public String[] getColumnTypes() throws SQLException
{
String[] result = new String[fields.size()];
for (int i = 0; i < fields.size(); i++)
{
String dbfType = "";
try
{
dbfType = fieldGetTypeMethod.invoke(fields.get(i)).toString();
}
catch (Exception e)
{
throw new SQLException(CsvResources.getString("dansDbfError") + ": " + e);
}
result[i] = dbfTypeToSQLType.get(dbfType);
if (result[i] == null)
throw new SQLException(CsvResources.getString("dbfTypeNotSupported") + ": " + dbfType);
}
return result;
}
@Override
public int[] getColumnSizes() throws SQLException
{
int[] result = new int[fields.size()];
for (int i = 0; i < fields.size(); i++)
{
try
{
Object fieldLength = fieldGetLengthMethod.invoke(fields.get(i));
result[i] = ((Number)fieldLength).intValue();
}
catch (Exception e)
{
throw new SQLException(CsvResources.getString("dansDbfError") + ": " + e);
}
}
return result;
}
@Override
public Map getEnvironment() throws SQLException
{
int initialSize = fields.size() * 2;
if (tableAlias != null)
initialSize += fields.size();
if (initialSize == 0)
initialSize = 1;
Map result = new MinimumMemoryMap<>(initialSize);
for (int i = 0; i < fields.size(); i++)
{
Object field = fields.get(i);
try
{
String fieldName = (String) fieldGetNameMethod.invoke(field, new Object[] {});
Object o = getField(i);
/*
* Convert column names to upper case because
* that is what query environment uses.
*/
fieldName = fieldName.toUpperCase();
result.put(fieldName, o);
result.put(upperTableName + "." + fieldName, o);
if (tableAlias != null)
{
/*
* Also allow field value to be accessed as S.ID if table alias S is set.
*/
result.put(tableAlias + "." + fieldName, o);
}
}
catch (Exception e)
{
throw new SQLException(CsvResources.getString("dansDbfError") + ": " + e);
}
}
return result;
}
@Override
public String getTableAlias()
{
return tableAlias;
}
}
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