Class Manager (version 0.20)

Description: A transaction manager class

Manager objects control layout and potentially other objects in the layout database and allow to queue operations to form transactions. A transaction is a sequence of operations that can be undone or redone.

In order to equip a layout object with undo/redo support, instantiate the layout object with a manager attached and embrace the operations to undo/redo with transaction/commit calls.

The use of transactions is subject to certain constraints, i.e. transacted sequences may not be mixed with non-transacted ones.

This class has been introduced in version 0.19.

Class overview

Index

Method Overview

transaction( string description ) Begin a transaction

commit Close a transaction.

undo Undo the current transaction

redo Redo the next available transaction

[const] bool has_undo? Determine if a transaction is available for 'undo'

[const] string transaction_for_undo Return the description of the next transaction for 'undo'

[const] bool has_redo? Determine if a transaction is available for 'redo'

[const] string transaction_for_redo Return the description of the next transaction for 'redo'

destroy Explicitly destroy the object

[const] bool destroyed Tell, if the object was destroyed

commit

Description: Close a transaction.

destroy

Description: Explicitly destroy the object

Explicitly destroy the object on C++ side if it was owned by the Ruby interpreter. Subsequent access to this object will throw an exception. If the object is not owned by Ruby, this method will do nothing.

[const] bool destroyed

Description: Tell, if the object was destroyed

This method returns true, if the object was destroyed, either explicitly or by the C++ side. The latter may happen, if the object is owned by a C++ object which got destroyed itself.

[const] bool has_redo?

Description: Determine if a transaction is available for 'redo'

returns: True, if a transaction is available.

[const] bool has_undo?

Description: Determine if a transaction is available for 'undo'

returns: True, if a transaction is available.

redo

Description: Redo the next available transaction

The next transaction is redone with this method. The 'has_redo' method can be used to determine wether there are transactions to undo.

transaction( string description )

Description: Begin a transaction

This call will open a new transaction. A transaction consists of a set of operations issued with the 'queue' method. A transaction is closed with the 'commit' method.

description: The description for this transaction.