Struct design_pattern_examples_rust::handlerchain::handlerchain_messagewindow::MessageWindow

pub struct MessageWindow {
    id: i32,
    title: String,
    window_box: WindowRectangle,
    close_box: WindowRectangle,
    selected: bool,
}

Represents a rectangular region that can handle messages directed to that region.

Note: The IMessageHandler interface is an example of a “Facade” design pattern, where the complexity of the MessageWindow is exposed only through a few methods to a system that only needs to deal with those few methods.

Fields

id: i32

Unique ID of this window.

title: String

Title/Name of this window.

window_box: WindowRectangle

Position of this window in global coordinates.

close_box: WindowRectangle

Position of the close window within the window box, although the coordinates are also global coordinates to eliminate the need to convert between window and global coordinates.

selected: bool

Whether this window has been selected (a button click occurred within the window).

Implementations

impl MessageWindow

pub fn new(title: &str, x: i32, y: i32, width: i32, height: i32) -> MessageWindow

Constructor

Parameters

• title

  Title of the MessageWindow.

• x

  X position of the upper left corner of the window’s region.

• y

  Y position of the upper left corner of the window’s region.

• width

  Width of the window’s region.

• height

  Height of the window’s region.

Returns

Returns a new instance of the MessageWindow struct.

fn handle_button_down_message(&mut self, message: &Message) -> MessageReturnTypes

Helper method to handle the ButtonDown message.

Parameters

• message

  A Message object describing the ButtonDown message.

Returns

Returns a value from the MessageReturnTypes enumeration indicating what action the caller should take. In this case, always return Continue so other handlers can react to the same message (assumes no windows are overlapping).

fn handle_button_up_message(&mut self, message: &Message) -> MessageReturnTypes

Helper method to handle the ButtonUp message.

Parameters

• message

  A Message object describing the ButtonUp message.

Returns

Returns a value from the MessageReturnTypes enumeration indicating what action the caller should take: (Stop) This message was handled and processing should stop, (Continue) this message can be passed on to other handlers, or (Close) this handler is closed so remove from the handlers list and stop further processing.

fn handle_close_message(&mut self, _message: &Message) -> MessageReturnTypes

Helper method to handle the Close message.

Parameters

• _message

  NOT USED.

Returns

Returns a value from the MessageReturnTypes enumeration indicating what action the caller should take. In this case, always return Close to indicate this handler should be removed from the handler list so no further messages can be sent to this window.

Trait Implementations

impl IMessageHandler for MessageWindow

fn id(&self) -> i32

ID of the window. This is used to uniquely identify a window in the collection.

fn process_message(&mut self, message: &Message) -> MessageReturnTypes

Called with a message for the window.

fn to_string(&self) -> String

Return a string representation of the message handler.