API reference - Class Manager

Notation used in Ruby API documentation

Description: A transaction manager class

• Public constructors
• Public methods
• Detailed description

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.

Public constructors

Public methods

Detailed description

void commit

Description: Close a transaction.

void create

Description: Ensures the C++ object is created

Use this method to ensure the C++ object is created, for example to ensure that resources are allocated. Usually C++ objects are created on demand and not necessarily when the script object is created.

void 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: Returns a value indicating whether the object was already 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'

[const] bool has_undo?

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

[const] bool is_const_object?

Description: Returns a value indicating whether the reference is a const reference

This method returns true, if self is a const reference. In that case, only const methods may be called on self.

[static] Manager new

Description: Creates a new object of this class

void 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.

unsigned int 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.

unsigned int transaction(string description,unsigned int join_with)

Description: Begin a joined transaction

This call will open a new transaction and join if with the previous transaction. The ID of the previous transaction must be equal to the ID given with 'join_with'.

This overload was introduced in version 0.22.

[const] string transaction_for_redo

Description: Return the description of the next transaction for 'redo'

[const] string transaction_for_undo

Description: Return the description of the next transaction for 'undo'

void undo

Description: Undo the current transaction

The current transaction is undone with this method. The 'has_undo' method can be used to determine wether there are transactions to undo.