Events and Data Flow

Events and Data Flow

MedICS components communicate through EventBus (pub/sub) and Qt signals (UI thread).

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Example flows

Theme change

Settings → ThemeManager.set_theme(id)
    → theme_changed (signal) → DockManager / widgets refresh
    → event_bus.emit('theme_changed', {...}) → subscribers

Workspace update (from Jupyter)

Jupyter kernel poll → MedICSMain.update_workspace_data(data)
    → WorkspaceManager.update_workspace_data(data, 'jupyter')
    → event_bus.emit('workspace_updated', {data, source})
    → DockManager / Variables tree refresh

Extension loaded

ExtensionManager.load_extension(id)
    → event_bus.emit('extension_loaded', {...})
    → MenuManager.refresh_extension_menu()
    → ToolbarManager.refresh_toolbar()

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EventBus catalog (common events)

Event	Typical source	Payload (conceptually)	Typical subscribers
component_state_changed	ApplicationComponent.set_state	{component, state}	monitoring
component_registered	MedICSMain	{name, component}	monitoring
workspace_updated	WorkspaceManager	{data, source}	DockManager, variables tree
folder_changed	WorkspaceManager	{folder}	file explorer
theme_changed	ThemeManager	{theme_id, stylesheet, …}	docks, toolbar
toolbox_loaded / toolbox_unloaded	ToolboxManager	toolbox info	Menu / Toolbar
extension_loaded / extension_unloaded	ExtensionManager	extension info	Menu / Toolbar
extensions_reloaded	ExtensionManager	reload results	MenuManager
file_selected	DockManager / Explorer	file path	toolboxes, extensions

Exact payload shapes may evolve; treat this table as a guide when wiring extensions.

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File loading flow (ImportData → workspace)

User drops file → ImportData
    → detect type
    → background worker (QThread) loads array / volume
    → preview
    → user confirms Import
    → workspace[name] = data
    → WorkspaceManager.update_workspace_data(...)
    → event_bus 'workspace_updated'
    → Variables tree + Jupyter namespace update

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Workspace save flow

File → Save Workspace (or auto-save timer)
    → WorkspaceManager.save_workspace_async()
    → background worker writes .med (HDF5)
    → status bar / UI feedback

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Extension guidance

When writing an extension:

1. Prefer reading/writing data through the workspace manager on app_context.
2. Subscribe to EventBus events you need; unsubscribe in cleanup().
3. Do UI work on the Qt main thread; use workers for heavy I/O.

See Extensions and Architecture.