syspolicy :: change :: ChangeSet :: Class ChangeSet

Class ChangeSet

This class represents a set of Change's that are to be implemented in the order they are appended to the ChangeSet. A ChangeSet is considered completed only when all the changes have been completed successfully.

A ChangeSet must be either accepted or rejected in it's entirety and no individual selection among the Change's is supported. This is a design requirement, since many times Changes depend on the previous ones.

Instance Methods

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__init__(self, changes=None)

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set_state(self, state)
This function accepts a new state for the ChangeSet and marks this state for all the contained Changes as well.

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check_state(self)
This function checks the state of the changes and updates the state of the ChangeSet if appropriate.

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get_state(self)
This function returns the state of the ChangeSet after checking it with self.check_state().

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append(self, change)
This function appends a Change to the ChangeSet.

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insert(self, position, change)
This function inserts a Change to the ChangeSet at position `position`.

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extend(self, changes)
This function extends the ChangeSet with a list of changes.

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merge(self, changeset)
This function merges the changes from another ChangeSet.

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Class Variables

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changes = None
an ordered list of Change elements creating the ChangeSet

state = 0
summarized state of the ChangeSet

Method Details

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set_state(self, state)

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This function accepts a new state for the ChangeSet and marks this state for all the contained Changes as well.

If the current state is STATE_PROPOSED, it can be changed to STATE_ACCEPTED, STATE_IGNORED or STATE_REJECTED.

If the current state is STATE_ACCEPTED, it can be changed to STATE_COMPLETED or STATE_FAILED.

Parameters:

state - The new state

Returns:

True if the state of the ChangeSet is `state`, False otherwise

check_state(self)

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This function checks the state of the changes and updates the state of the ChangeSet if appropriate. The checking is performed only when the ChangeSet has been accepted.

The state is changed to completed when all the changes have been completed and the state is changed to failed when a change is found that is not in the completed nor unhandled state.