notification_notification_cangjie_wrapper(beta feature)

Introduction

The notification_notification_cangjie_wrapper provides common event management capabilities for developers using the Cangjie language for application development on OpenHarmony. OpenHarmony provides applications with the ability to subscribe, publish, and unsubscribe from common events through CES (Common Event Service). The currently open notification_notification_cangjie_wrapper only supports standard devices.

Common events can be divided into system common events and custom common events.

• System common events: The system collects event information and sends it to user programs that have subscribed to the event according to system policies. For example: system events published by key system services, HAP installation, update, uninstallation, etc.

• Custom common events: Applications customize some common events to implement cross-application event communication capabilities.

Each application can subscribe to common events as needed. If an application subscribes successfully and the corresponding subscribed common event is published, the system will send it to the application. These common events may come from the system, other applications, and the application itself.

System Architecture

Figure 1 notification_cangjie_wrapper architecture

As shown in the architecture diagram, the notification Cangjie API provides the capabilities to publish common events, create subscribers, subscribe, and unsubscribe.

Interface Layer:

• CommonEventManager: Provides common event management capabilities for developers, including createSubscriber, subscribe, unsubscribe, and publish.
  • createSubscriber: Provides developers with the interface capability to create common event subscribers based on subscription information, where the subscription information can specify the subscribed common events, permissions required by event publishers, and set the subscriber's priority, etc.
  • subscribe: Provides developers with the subscription interface capability for specified subscribers, used to obtain relevant information about subscribed common events and set common event processing information.
  • unsubscribe: Provides developers with the unsubscribe interface capability for specified subscribers.
  • publish: Provides developers with the interface capability to publish common events with specified content and attributes.

Framework Layer:

• CommonEventManager Wrapper: Implements common event management wrapper based on the underlying common event service, including the capabilities to create subscribers, subscribe, publish, and unsubscribe from common events.

Dependency Components Introduction in Architecture:

• common_event_service: Depends on the common event service for framework layer capability implementation.
• hiviewdfx_cangjie_wrapper: Depends on HiLog capabilities for printing logs at key points.
• cangjie_ark_interop: Depends on APILevel class definitions and BusinessException class definitions for API annotation and throwing exceptions to users in error branches.

Directory Structure

base/notification/notification_cangjie_wrapper
├── figures         # architecture pictures
└── ohos            # Cangjie notification interface implementation
│   ├── common_event_data           # Common event data module
│   ├── common_event_manager        # Common event management module
│   ├── common_event_publish_data   # Common event publish data module
│   ├── common_event_subscribe_info # Common event subscribe info module
│   ├── common_event_subscriber     # Common event subscriber module
│   └── value_type                  # Common event multi-value type implementation
└── test            # Cangjie notification test cases
    └── common_event_manager # Common event test cases

Usage

The current notification Cangjie API provides the following functions:

• CommonEventManager.

For common event related APIs, please refer to ohos.common_event_manager. For related guidelines, please refer to Common Event Development Guide.

Constraints

Compared to ArkTS API, the following functions are not supported:

• The ability to send and process events between different threads within the same process or within the same thread.
• User notification service.

Code Contribution

Developers are welcome to contribute code, documentation, etc. For specific contribution processes and methods, please refer to Code Contribution.

Repositories Involved

arkcompiler_cangjie_ark_interop

hiviewdfx_hiviewdfx_cangjie_wrapper

notification_common_event_service