net.java.trueupdate.manager.spec.cmd

Class AbstractCommand

java.lang.Object

net.java.trueupdate.manager.spec.cmd.AbstractCommand

All Implemented Interfaces:

Command

public abstract class AbstractCommand
extends Object
implements Command

A base class for commands which need a separate start method.

Author:

Christian Schlichtherle

Constructor Summary

Constructors

Constructor and Description
AbstractCommand()

Method Summary

Modifier and Type	Method and Description
protected abstract void	doPerform() Performs this command, thereby creating some durable side effects.
protected abstract void	doRevert() Reverts any durable side effects of the perform() method.
protected abstract void	doStart() Starts this command.
void	perform() Performs this command, thereby creating some durable side effects.
void	revert() Reverts any durable side effects of the Command.perform() method.

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractCommand

public AbstractCommand()

Method Detail

doPerform

protected abstract void doPerform()
                           throws Exception

Performs this command, thereby creating some durable side effects. If this method throws an exception, then revert() must get called.

Throws:

Exception

doRevert

protected abstract void doRevert()
                          throws Exception

Reverts any durable side effects of the perform() method. If this method fails with an exception, then the state of the system may be corrupted.

Throws:

Exception

doStart

protected abstract void doStart()
                         throws Exception

Starts this command. This method must not have any durable side effects. If this method fails, neither doPerform() nor doRevert() get called.

Throws:

Exception

perform

public final void perform()
                   throws Exception

Description copied from interface: Command

Performs this command, thereby creating some durable side effects. If this method throws an exception, then Command.revert() must get called.

Specified by:

perform in interface Command

Throws:

Exception

revert

public final void revert()
                  throws Exception

Description copied from interface: Command

Reverts any durable side effects of the Command.perform() method. If this method fails with an exception, then the state of the system may be corrupted.

Specified by:

revert in interface Command

Throws:

Exception