Concept - Dialog Migration from 4.5.x to 5.x

public class CustomSaveActionDefinition extends SaveDialogActionDefinition {
    public CustomSaveActionDefinition() {
		// This allows you to directly register your action
        setImplementationClass(CustomSaveAction.class);
    }
}

public class CustomSaveAction extends SaveDialogAction {
    public CustomSaveAction(CustomSaveActionDefinition definition, Item item, EditorValidator validator, EditorCallback callback) {
        super(definition, item, validator, callback);
    }
    @Override
    public void execute() throws ActionExecutionException {
        // First Validate
        validator.showValidation(true);
        if (validator.isValid()) {
			// Get the JcrNodeAdapter that contains all field properties 
            final JcrNodeAdapter itemChanged = (JcrNodeAdapter) item;
            try {
                String fieldPropertyText = itemChanged.getItemProperty("fieldPropertyText").toString();
				// Manipulate the data, and do your business logic 
				...
				// Once this is done, set the transformed value to the itemChanged if you want that they are persisted on the related JCR node 
				// The related node will be updated based on the item value by the following call:
                final Node node = itemChanged.applyChanges();
				
				node.getSession().save();

 public class CustomActionCreator implements ActionCreator {
    private final String name;
    private final String label;
	private final String myCustomProperty;
    private final String className;
    public BaseActionCreator(String name, String label, String className, String myCustomProperty) {
        this.className = className;
        this.label = label;
        this.name = name;
 		this.myCustomProperty = myCustomProperty;
    }
    @Override
    public void create(Node actionsNode) throws RepositoryException {
		// Create the action node
        Node actionNode = actionsNode.addNode(this.name, NodeTypes.ContentNode.NAME);
		// Create the properties
        actionNode.setProperty("label", this.label);
        actionNode.setProperty("class", this.className);
		....
    }

/**
 * Field Migration task for the specific Form fields.
 */
public class CustomDialogMigrationTask extends DialogMigrationTask {
    public CustomDialogMigrationTask(String moduleName) {
        super(moduleName);
    }
    @Override
    protected void registerActionsForDialogToCreate(HashMap<String, List<ActionCreator>> dialogActionsToMigrate) {
        // Register the Custom Save Action
        ActionCreator saveAction = new CustomActionCreator("commit", "save changes", CustomSaveAction.class.getName(), "myProperty");
        // Register a standard Cancel Action
        ActionCreator cancelAction = new BaseActionCreator("cancel", "cancel", "info.magnolia.ui.admincentral.dialog.action.CancelDialogActionDefinition");
        // Create an entry
        dialogActionsToMigrate.put("dialogName", Arrays.asList(saveAction, cancelAction));
    } 

public class CustomDialogMigrationTask extends DialogMigrationTask {
    public CustomDialogMigrationTask(String moduleName) {
        super(moduleName);
    }

    @Override
    protected void registerControlsToMigrate(HashMap<String, ControlMigrator> controlsToMigrate) {
  		// Define your custom types 
  		controlsToMigrate.put("dateControl", new DateControlMigration()); 
  		....

    @Inject
    public CustomModuleVersionHandler(ControlMigratorsRegistry controlMigratorsRegistry) {
        // Register control migration task.
        controlMigratorsRegistry.register("dateControl", new DateControlMigration()); 
        ....
		
		register(DeltaBuilder.update("2.2", "")
        
		// migrate dialogs to magnolia 5 dialogs
        .addTask(new DialogMigrationTask("myCustomModule"))

/** 
* Migrate an custom dateControl to a DateField. 
*/ 
public class CustomDateControlMigration implements DateControlMigration { 

	@Override 
	public void migrate(Node controlNode) throws RepositoryException { 
		super.migrate(controlNode); 
		// Remove the first property 
		Property dateTimeProperty = controlNode.getProperty("dateTime"); 
		PropertyUtil.renameProperty(dateTimeProperty, "time"); 
		// Split the second property 
		Property formatProperty = controlNode.getProperty("dateTimeFormat"); 
		controlNode.setProperty("dateFormat",StringUtils.left(formatProperty.getString(), StringUtils.indexOf(formatProperty.getString(), ":"))); 
		controlNode.setProperty("timeFormat",StringUtils.right(formatProperty.getString(), StringUtils.indexOf(formatProperty.getString(), ":"))+1); 
		formatProperty.remove(); 
	} 
}

public class CustomDialogMigrationTask extends DialogMigrationTask { 
	.... 
	@Override
    protected void registerControlsToMigrate(HashMap<String, ControlMigrator> controlsToMigrate) {	
		// Define your custom types 
		controlsToMigrate.put("dateControl", new CustomDateControlMigration()); 
        ....

public class StaticCustomFieldFactory extends StaticFieldFactory<StaticCustomFieldDefinition> { 
	private static final Logger log = LoggerFactory.getLogger(StaticCustomFieldFactory.class); 
	
	// Injected factory private MyFactory factory; 
	@Inject 
	public StaticCustomFieldFactory(StaticCustomFieldDefinition definition, Item relatedFieldItem, MyFactory factory) { 
		super(definition, relatedFieldItem); 
		this.factory = factory; 
	} 

	@Override public String createFieldValue() { 
		String value = ""; 
		try { 
			// put your logic here 
			this.factory.do(... 
			... 
		} 
		return value; 
	}

/** 
 * Definition used for create a StaticFormField. 
 */ 
public class StaticCustomFieldDefinition extends StaticFieldDefinition { }

public class StaticCustomControlMigrator implements ControlMigrator {
    @Override
    public void migrate(Node controlNode) throws RepositoryException {
        controlNode.getProperty("controlType").remove();
        controlNode.setProperty("class", StaticCustomFieldDefinition.class.getName());
		...
    }
}

public class CustomDialogMigrationTask extends DialogMigrationTask { 
    .... 
    @Override
    protected void registerControlsToMigrate(HashMap<String, ControlMigrator> controlsToMigrate) {    
        // Define your custom types 
        controlsToMigrate.put("dateControl", new CustomDateControlMigration()); 
		controlsToMigrate.put("myControl", new StaticCustomControlMigrator()); 
        ....

public class CustomDialogMigrationTask extends DialogMigrationTask { 
        
	public CustomDialogMigrationTask(String moduleName) {
        super(moduleName);
    }

	@Override
    protected void registerActionsForDialogToCreate(HashMap<String, List<ActionCreator>> dialogActionsToMigrate) {
        // Register the Custom Save Action
        ActionCreator saveAction = new CustomActionCreator("commit", "save changes", CustomSaveAction.class.getName(), "myProperty");
        // Register a standard Cancel Action
        ActionCreator cancelAction = new BaseActionCreator("cancel", "cancel", "info.magnolia.ui.admincentral.dialog.action.CancelDialogActionDefinition");
        // Create an entry
        dialogActionsToMigrate.put("dialogName", Arrays.asList(saveAction, cancelAction));
    } 

    @Override
    protected void registerControlsToMigrate(HashMap<String, ControlMigrator> controlsToMigrate) {    
        // Define your custom types 
        controlsToMigrate.put("dateControl", new CustomDateControlMigration()); 
		controlsToMigrate.put("myControl", new StaticCustomControlMigrator()); 
    }