Bug 318813

Comment 1 Patrick Tessier 2010-11-30 06:13:24 EST

Done in the revision 3383

The emf set command when it is used in the context of a change of container
	create only an add command. So during the undo there was no add in the old container and we see only as a remove.
	
	So to solve it, I had explicitly a remove command before. For the do it is unuseful but for the undo  it is useful to add into the old container
	
	//before modification the code was:
	commandList.add(SetCommand.create(domain, targetOwner, eStructuralFeature, tmp));

//after modification it is:
Command emfCommand= RemoveCommand.create(domain, childElement);
				emfCommand=emfCommand.chain( SetCommand.create(domain, targetOwner, eStructuralFeature, tmp));
				commandList.add(emfCommand);
				
Moreover Set command can return unoable command see the comment of this class
/**
 * The set command logically acts upon an owner object to set a particular feature to a specified value or to unset a feature.
 * The static create methods delegate command creation to {@link EditingDomain#createCommand EditingDomain.createCommand},
 * which may or may not result in the actual creation of an instance of this class.
 *
 * <p>
 * The implementation of this class is low-level and EMF specific;
 * it allows a value to be set to a single-valued feature of an owner,
 * i.e., it is equivalent of the call
 * <pre>
 *   ((EObject)object).eSet((EStructuralFeature)feature, value);
 * </pre>
 * or to 
 * <pre>
 *   ((EObject)object).eUnset((EStructuralFeature)feature);
 * </pre>
 * if the value is {@link #UNSET_VALUE}.
 * <p>
 * Setting a feature that is a bidirectional reference with a multiplicity-many reverse or with a
 * multiplicity-1 reverse that is already set (on value), is not undoable.
 * In this case, the SetCommand static create function will not return an instance of this class, but
 * instead will return a compound command (e.g., a {@link RemoveCommand} followed by an {@link AddCommand}
 * for the other end of the relation) which could not be undone.
 * <p>
 * The exception to the above is when an empty list is being set to empty or unset. Such commands are undoable
 * and represent the only way to toggle whether the feature is set.
 * <p>
 * When setting a containment (or container) feature, we always assume that the object that will be
 * contained is not already in a container, but take no action in this class to ensure this is the case. 
 * <p>
 * A set command is an {@link OverrideableCommand}.
 */