net.sourceforge.jdbdump.connect.connectors
Class PostgresqlConnector

java.lang.Object
  net.sourceforge.jdbdump.connect.DatabaseConnector
      net.sourceforge.jdbdump.connect.connectors.PostgresqlConnector

public class PostgresqlConnector
extends DatabaseConnector

This is a class handling connection to the database, an implementation of the abstract class DatabaseConnector. It is a specific connector, providing connection to PostgreSQL databases.

Author:

jsuder

See Also:

DatabaseConnector

Field Summary

protected int	columns Number of columns in the current table.
protected java.sql.ResultSet	dataSet A ResultSet storing table data when it is being downloaded.
static int	FETCH_SIZE Maximum number of table records downloaded at a time.
protected int	position Number of current record in a table while it is being downloaded.
protected java.lang.String	query The query used to download next parts of a table into dataSet.

Fields inherited from class net.sourceforge.jdbdump.connect.DatabaseConnector

connection, meta

Constructor Summary

PostgresqlConnector()

Method Summary

protected void	clearConstraints(Table table) Removes constraints from the database's tables (if they exist), before they are dropped from the database and then inserted from a dump.
protected void	clearDatabase(Dump dump) Clears tables from the database if they already exist, before they are inserted from a dump.
void	connect(java.lang.String url, java.lang.String user, java.lang.String pass) Opens a connection to the database, using the provided connection data.
java.lang.String	createURL(DatabaseConnectionData data) Creates a PostgreSQL-specific JDBC connection url (it has the form: jdbc:postgresql://host:port/database).
Dump	dump() Creates a backup of the structure of the entire database.
protected void	dumpColumn(Column column, java.sql.ResultSet rsColumns) Downloads the structure of a single table column from the database.
protected void	dumpTableForeignKeys(Table table) Downloads the table's foreign (imported) keys from the database.
protected void	dumpTablePrimaryKeys(Table table) Downloads the table's primary key from the database.
java.lang.String[]	getTableDataLine() Downloads one record of data from the previously initialized table in database.
void	initializeTableData(java.lang.String tableName) Prepares the given table for downloading its data.
void	restore(Dump dump) Restores the structure of the database from a Dump object loaded from a previously created backup file.
protected void	restoreTableConstraints(Table table) Restores the table's constraints (e.g.
protected void	restoreTableData(Table table) Restores the table's data into the database.
protected void	restoreTableStructure(Table table) Creates a single table using information from a dump.

Methods inherited from class net.sourceforge.jdbdump.connect.DatabaseConnector

connect, disconnect, dumpTable, dumpTables, printResultSet

Methods inherited from class java.lang.Object

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

Field Detail

dataSet

protected java.sql.ResultSet dataSet

A ResultSet storing table data when it is being downloaded.

query

protected java.lang.String query

The query used to download next parts of a table into dataSet.

position

protected int position

Number of current record in a table while it is being downloaded.

columns

protected int columns

Number of columns in the current table.

FETCH_SIZE

public static final int FETCH_SIZE

Maximum number of table records downloaded at a time.

See Also:

Constant Field Values

Constructor Detail

PostgresqlConnector

public PostgresqlConnector()

Method Detail

connect

public void connect(java.lang.String url,
                    java.lang.String user,
                    java.lang.String pass)
             throws java.sql.SQLException,
                    java.lang.ClassNotFoundException

Opens a connection to the database, using the provided connection data.

Specified by:

connect in class DatabaseConnector

Parameters:

url - a correct connection URL

user - user's login in the database

pass - user's password

Throws:

java.sql.SQLException - if the connection is not possible

java.lang.ClassNotFoundException - if there is a problem with loading a driver

dump

public Dump dump()

Creates a backup of the structure of the entire database. It doesn't backup any data.

Specified by:

dump in class DatabaseConnector

Returns:

a Dump object containing information about database structure

Throws:

java.sql.SQLException - if the backup process is interrupted by a critical error

dumpTablePrimaryKeys

protected void dumpTablePrimaryKeys(Table table)
                             throws java.sql.SQLException

Downloads the table's primary key from the database. This method implements the empty method dumpTablePrimaryKeys() in the superclass, so is will be called by superclass's dumpTable() after it retrieves all the columns.

Overrides:

dumpTablePrimaryKeys in class DatabaseConnector

Parameters:

table - a table which should be checked for primary keys

Throws:

java.sql.SQLException - if the backup process is interrupted by a critical error

dumpTableForeignKeys

protected void dumpTableForeignKeys(Table table)
                             throws java.sql.SQLException

Downloads the table's foreign (imported) keys from the database. This method implements the empty method dumpTableForeignKeys() in the superclass, so is will be called by superclass's dumpTable() after it retrieves all the columns.

Overrides:

dumpTableForeignKeys in class DatabaseConnector

Parameters:

table - a table which should be checked for foreign keys

Throws:

java.sql.SQLException - if the backup process is interrupted by a critical error

dumpColumn

protected void dumpColumn(Column column,
                          java.sql.ResultSet rsColumns)
                   throws java.sql.SQLException

Downloads the structure of a single table column from the database. This method overrides the method in superclass and will be called by superclass's dumpTable() for each column in a table. The specific behaviour which is needed for PostgreSQL is renaming the 'bpchar' data type to 'char'.

Overrides:

dumpColumn in class DatabaseConnector

Parameters:

column - a column which should have its parameters downloaded

rsColumns - a ResultSet returned by DatabaseMetaData.getColumns(), set on this column's record

Throws:

java.sql.SQLException - if the backup process is interrupted by a critical error

restore

public void restore(Dump dump)
             throws java.sql.SQLException

Restores the structure of the database from a Dump object loaded from a previously created backup file. It doesn't restore any data.

Specified by:

restore in class DatabaseConnector

Parameters:

dump - a Dump object containing information about database structure

Throws:

java.sql.SQLException - if the restore process is interrupted by a critical error

clearDatabase

protected void clearDatabase(Dump dump)
                      throws java.sql.SQLException

Clears tables from the database if they already exist, before they are inserted from a dump. This method is called by restore().

Parameters:

dump - the dump which contains names of the tables which should be cleared

Throws:

java.sql.SQLException - if the clear process is interrupted by a critical error

clearConstraints

protected void clearConstraints(Table table)
                         throws java.sql.SQLException

Removes constraints from the database's tables (if they exist), before they are dropped from the database and then inserted from a dump. This method is called by clearDatabase() and is needed because it may not be possible to drop some of the tables if they have constraints binding them to other tables.

Parameters:

table - the table which contains constraints which should be removed

Throws:

java.sql.SQLException - if the clear process is interrupted by a critical error

restoreTableStructure

protected void restoreTableStructure(Table table)
                              throws java.sql.SQLException

Creates a single table using information from a dump. It restores all the fields, also adds a primary key if there is one, but doesn't upload any data yet and doesn't add constraints other than the primary key.

Parameters:

table - the table which should be added to the database

Throws:

java.sql.SQLException - if the create process is interrupted by a critical error

restoreTableConstraints

protected void restoreTableConstraints(Table table)
                                throws java.sql.SQLException

Restores the table's constraints (e.g. foreign keys). This method is called at the end of restoring process, after the data is uploaded, because otherwise we would have to find a correct order in which to download the data to prevent any conflicts.

Parameters:

table - the table whose constraints should be added

Throws:

java.sql.SQLException

restoreTableData

protected void restoreTableData(Table table)
                         throws java.sql.SQLException

Restores the table's data into the database. The data are loaded from the backup file record after record just before they are uploaded into the database.

Parameters:

table - the table whose data should be uploaded

Throws:

java.sql.SQLException - when the data can't be uploaded

createURL

public java.lang.String createURL(DatabaseConnectionData data)

Creates a PostgreSQL-specific JDBC connection url (it has the form: jdbc:postgresql://host:port/database).

Specified by:

createURL in class DatabaseConnector

Parameters:

data - an object providing all the data necessary to open the connection

Returns:

a connection url string generated from the data

initializeTableData

public void initializeTableData(java.lang.String tableName)
                         throws java.sql.SQLException

Prepares the given table for downloading its data. That means, it runs a query "SELECT * FROM tablename" and stores the received result set.

Specified by:

initializeTableData in class DatabaseConnector

Parameters:

tableName - name of the table from which data should be downloaded

Throws:

java.sql.SQLException

getTableDataLine

public java.lang.String[] getTableDataLine()
                                    throws java.sql.SQLException

Downloads one record of data from the previously initialized table in database.

Specified by:

getTableDataLine in class DatabaseConnector

Returns:

next record from the table, or null if there are no more records

Throws:

java.sql.SQLException - if data record can't be downloaded because of a connection error or an error in the database