org.melati.poem
Class PreparedStatementFactory

java.lang.Object
  org.melati.poem.util.CachedIndexFactory
      org.melati.poem.PreparedStatementFactory

All Implemented Interfaces:

IndexFactory

public class PreparedStatementFactory
extends CachedIndexFactory

Maintains a cache of PreparedStatements for an SQL statement string.

The cached contents are discarded if the database structure has changed since the cache was created.

Execution of the statement in a transaction reflects uncommitted changes in that transaction.

The supertype dictates that connections can be indentified by index, but this is slightly complicated and the additional methods rely on transactions instead.

Constructor Summary

PreparedStatementFactory(Database database, String sql)
Constructor.

Method Summary

Object	get(int index) Get either from cache or, failing that, really get it.
PreparedStatement	preparedStatement()
PreparedStatement	preparedStatement(PoemTransaction transaction) Get a new or cached PreparedStatement.
protected Object	reallyGet(int index) Obtain a fresh PreparedStatement for a connection identified by an index.
ResultSet	resultSet()
protected ResultSet	resultSet(SessionToken token)
protected ResultSet	resultSet(SessionToken token, PreparedStatement statement)
String	toString()

Methods inherited from class org.melati.poem.util.CachedIndexFactory

invalidate, invalidate

Methods inherited from class java.lang.Object

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

Constructor Detail

PreparedStatementFactory

public PreparedStatementFactory(Database database,
                                String sql)

Constructor.

Parameters:

database - the db we are working with

sql - the SQL statement

Method Detail

reallyGet

protected Object reallyGet(int index)

Obtain a fresh PreparedStatement for a connection identified by an index.

The index is zero for the commited connection and the transaction index plus 1 for current transactions.

Specified by:

reallyGet in class CachedIndexFactory

Parameters:

index - of the item, possibly a troid

Returns:

the cached Object

get

public Object get(int index)

Get either from cache or, failing that, really get it.

Specified by:

get in interface IndexFactory

Overrides:

get in class CachedIndexFactory

Parameters:

index - the index

Returns:

the object

See Also:

CachedIndexFactory.get(int)

preparedStatement

public PreparedStatement preparedStatement(PoemTransaction transaction)

Get a new or cached PreparedStatement.

Parameters:

transaction - the PoemTransaction, can be null

Returns:

a new or cached PreparedStatement

preparedStatement

public final PreparedStatement preparedStatement()

Returns:

a new or cached PreparedStatement for the current PoemThread's transaction.

resultSet

protected ResultSet resultSet(SessionToken token,
                              PreparedStatement statement)

resultSet

protected final ResultSet resultSet(SessionToken token)

resultSet

public final ResultSet resultSet()

Returns:

the ResultSet from the PreparedStatement of the PoemThread

toString

public String toString()

Overrides:

toString in class Object

See Also:

Object.toString()