edu.upc.dama.dex.io
Class JDBCReader

java.lang.Object
  edu.upc.dama.dex.io.JDBCReader

All Implemented Interfaces:

RowReader

public class JDBCReader
extends java.lang.Object
implements RowReader

A very simple JDBC reader.

This reader allows for getting rows from a relational database using the JDBC interface.
To use it you must get the JDBC driver of your database.
After this, you can execute a query over the database and get the result row by row.

 Basic example using a MySQL database:

 RowReader rl = new JDBCReader("com.mysql.jdbc.Driver", "jdbc:mysql://localhost/example", "SELECT * FROM `test` ");
 String[] r;
 while ((r = rl.readNext()) != null) {
   for (int i = 0; i < r.length; i++) {
     System.out.println(r[i]);
   }
 }
 

Author:

Sparsity Technologies

Constructor Summary

JDBCReader(java.lang.String driverUrl, java.lang.String url, java.lang.String query)
Creates a new instance of JDBCReader.

JDBCReader(java.lang.String driverUrl, java.lang.String protocol, java.lang.String database, java.lang.String query)
Creates a new instance of JDBCReader.

JDBCReader(java.lang.String driverUrl, java.lang.String url, java.lang.String user, java.lang.String password, java.lang.String query)
Creates a new instance of JDBCReader.

Method Summary

void	close() Closes the underlying reader.
int	getRow() The row number for the current row.
java.lang.String[]	readNext() Reads the next row as a string array.
boolean	reset() Moves the reader to the first row of the result of the query.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

JDBCReader

public JDBCReader(java.lang.String driverUrl,
                  java.lang.String protocol,
                  java.lang.String database,
                  java.lang.String query)
           throws java.io.IOException

Creates a new instance of JDBCReader.

Parameters:

driverUrl - JDBC driver url .

protocol - Protocol to be used for the JDBC connection.

database - Name of the database.

query - Query to be executed on the database.

Throws:

java.io.IOException

JDBCReader

public JDBCReader(java.lang.String driverUrl,
                  java.lang.String url,
                  java.lang.String query)
           throws java.io.IOException

Creates a new instance of JDBCReader.

Parameters:

driverUrl - JDBC driver url

url - JDBC url connection to the database.

query - Query to be executed on the database.

Throws:

java.io.IOException

JDBCReader

public JDBCReader(java.lang.String driverUrl,
                  java.lang.String url,
                  java.lang.String user,
                  java.lang.String password,
                  java.lang.String query)
           throws java.io.IOException

Creates a new instance of JDBCReader.

Parameters:

driverUrl - JDBC driver url

url - JDBC url connection to the database.

user - Username of the database.

password - Password of to the database.

query - Query to be executed on the database.

Throws:

java.io.IOException

Method Detail

reset

public boolean reset()
              throws java.io.IOException

Moves the reader to the first row of the result of the query.

Restarts the reader.

Specified by:

reset in interface RowReader

Returns:

true.

Throws:

java.io.IOException - If bad things happen.

readNext

public java.lang.String[] readNext()
                            throws java.io.IOException

Reads the next row as a string array.

Specified by:

readNext in interface RowReader

Returns:

A string array with each comma-separated element as a separate entry.

Throws:

java.io.IOException - If bad things happen during the read.

close

public void close()
           throws java.io.IOException

Closes the underlying reader.

Specified by:

close in interface RowReader

Throws:

java.io.IOException - If the close fails.

getRow

public int getRow()
           throws java.io.IOException

The row number for the current row.

Specified by:

getRow in interface RowReader

Returns:

The current row number; 0 if there is no current row.

Throws:

java.io.IOException - If it fails.