helma.objectmodel.db
Class Transactor

java.lang.Object
  helma.objectmodel.db.Transactor

public class Transactor
extends java.lang.Object

A subclass of thread that keeps track of changed nodes and triggers changes in the database when a transaction is commited.

Field Summary

protected ITransaction

txn

Method Summary

void	abort() Abort the current transaction, rolling back all changes made.
void	begin(java.lang.String name) Start a new transaction with the given name.
void	closeConnections() Closes all open JDBC connections
void	commit() Commit the current transaction, persisting all changes to DB.
void	dropCleanNode(Key key) Drop a reference to an unmodified Node previously registered with visitCleanNode().
void	dropDirtyNode(Node node) Unmark a Node that has previously been marked as modified during the transaction
Node	getCleanNode(java.lang.Object key) Get a reference to an unmodified Node local to this transaction
java.sql.Connection	getConnection(DbSource src) Get a db connection that was previously registered with this transactor thread.
Node	getDirtyNode(Key key) Get a dirty Node from this transaction.
static Transactor	getInstance() Get the transactor for the current thread or null if none exists.
static Transactor	getInstance(NodeManager nmgr) Get the transactor for the current thread, creating a new one if none exists.
static Transactor	getInstanceOrFail() Get the transactor for the current thread or throw a IllegalStateException if none exists.
java.lang.String	getTransactionName() Return the name of the current transaction.
boolean	isActive() Returns true if a transaction is currently active.
boolean	isAlive() Check whether the thread associated with this transactor is alive.
void	kill() Kill this transaction thread.
void	registerConnection(DbSource src, java.sql.Connection con) Register a db connection with this transactor thread.
java.lang.String	toString() Return a string representation of this Transactor thread
void	visitCleanNode(Key key, Node node) Keep a reference to an unmodified Node local to this transaction
void	visitCleanNode(Node node) Keep a reference to an unmodified Node local to this transaction
void	visitDirtyNode(Node node) Mark a Node as modified/created/deleted during this transaction
void	visitParentNode(Node node)

Methods inherited from class java.lang.Object

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

Field Detail

txn

protected ITransaction txn

Method Detail

getInstance

public static Transactor getInstance()

Get the transactor for the current thread or null if none exists.

Returns:

the transactor associated with the current thread

getInstanceOrFail

public static Transactor getInstanceOrFail()
                                    throws java.lang.IllegalStateException

Get the transactor for the current thread or throw a IllegalStateException if none exists.

Returns:

the transactor associated with the current thread

Throws:

java.lang.IllegalStateException - if no transactor is associated with the current thread

getInstance

public static Transactor getInstance(NodeManager nmgr)

Get the transactor for the current thread, creating a new one if none exists.

Parameters:

nmgr - the NodeManager used to create the transactor

Returns:

the transactor associated with the current thread

visitDirtyNode

public void visitDirtyNode(Node node)

Mark a Node as modified/created/deleted during this transaction

Parameters:

node - ...

dropDirtyNode

public void dropDirtyNode(Node node)

Unmark a Node that has previously been marked as modified during the transaction

Parameters:

node - ...

getDirtyNode

public Node getDirtyNode(Key key)

Get a dirty Node from this transaction.

Parameters:

key - the key

Returns:

the dirty node associated with the key, or null

visitCleanNode

public void visitCleanNode(Node node)

Keep a reference to an unmodified Node local to this transaction

Parameters:

node - the node to register

visitCleanNode

public void visitCleanNode(Key key,
                           Node node)

Keep a reference to an unmodified Node local to this transaction

Parameters:

key - the key to register with

node - the node to register

dropCleanNode

public void dropCleanNode(Key key)

Drop a reference to an unmodified Node previously registered with visitCleanNode().

Parameters:

key - the key

getCleanNode

public Node getCleanNode(java.lang.Object key)

Get a reference to an unmodified Node local to this transaction

Parameters:

key - ...

Returns:

...

visitParentNode

public void visitParentNode(Node node)

Parameters:

node - ...

isActive

public boolean isActive()

Returns true if a transaction is currently active.

Returns:

true if currently a transaction is active

isAlive

public boolean isAlive()

Check whether the thread associated with this transactor is alive. This is a proxy to Thread.isAlive().

Returns:

true if the thread running this transactor is currently alive.

registerConnection

public void registerConnection(DbSource src,
                               java.sql.Connection con)

Register a db connection with this transactor thread.

Parameters:

src - the db source

con - the connection

getConnection

public java.sql.Connection getConnection(DbSource src)

Get a db connection that was previously registered with this transactor thread.

Parameters:

src - the db source

Returns:

the connection

begin

public void begin(java.lang.String name)
           throws java.lang.Exception

Start a new transaction with the given name.

Parameters:

name - The name of the transaction. This is usually the request path for the underlying HTTP request.

Throws:

java.lang.Exception - ...

commit

public void commit()
            throws java.lang.Exception

Commit the current transaction, persisting all changes to DB.

Throws:

java.lang.Exception - ...

abort

public void abort()

Abort the current transaction, rolling back all changes made.

kill

public void kill()

Kill this transaction thread. Used as last measure only.

closeConnections

public void closeConnections()

Closes all open JDBC connections

getTransactionName

public java.lang.String getTransactionName()

Return the name of the current transaction. This is usually the request path for the underlying HTTP request.

toString

public java.lang.String toString()

Return a string representation of this Transactor thread

Overrides:

toString in class java.lang.Object

Returns:

...