Message Hub API

Ⅰ、Class Overview

MessageHub is the core class for message processing, used to manage message transmission and status control in applications. It supports different levels of messages (debug, info, success, warning, error) and determines the front-end display form and business process control (such as whether to interrupt operations) based on the message level and configuration. Obtain the instance through PamirsSession.getMessageHub().

Ⅱ、Member Variables

Variable Name	Type	Description
`success`	boolean	Whether successful (does not include ERROR-level messages), default `true` . Automatically set to `false` when ERROR messages exist. .
`exception`	boolean	Whether it is an exception state (not explicitly used in the code, possibly reserved for extension).
`dataExtension`	`DataExtension`	Stores non-error messages (INFO, SUCCESS, WARN, etc.) and extended data.
`errorExtension`	`ErrorExtension`	Stores error messages (ERROR level) and error details (code, type, etc.).
`path`	`ClientExecutionPath`	The execution path associated with the message, used to locate the front-end display position (such as field-level errors).

Ⅲ、Constructor

(Ⅰ) `MessageHub()`

Description: Default constructor, initializes success to true.
Return Value: MessageHub instance.

Ⅳ、Core Methods

(Ⅰ) Message Addition Methods

1. `msg(Message message)`

Description: Adds a single message. Determines whether to store it in dataExtension (non-ERROR) or errorExtension (ERROR) based on the message level (InformationLevelEnum).
Parameter: message - Message instance, which needs to set level and message.
Return Value: MessageHub instance (supports chaining).
Example: java

PamirsSession.getMessageHub()
    .msg(Message.init()
        .setLevel(InformationLevelEnum.ERROR)
        .setField("name")
        .setMessage("名称为必填项"));

2. `msg(List<Message> messages)`

Description: Adds messages in batches, processing each by calling msg().
Parameter: messages - Message list.
Return Value: MessageHub instance.

3. Quick Level Methods (`info`, `warn`, `success`, `error`)

Method Name	Description	Parameter	Return Value
`info(String msg)`	Adds an INFO-level message	`msg` - Message content	`MessageHub`
`warn(String msg)`	Adds a WARN-level message	`msg` - Message content	`MessageHub`
`success(String msg)`	Adds a SUCCESS-level message	`msg` - Message content	`MessageHub`
`error(String msg)`	Adds an ERROR-level message and automatically sets `success=false`	`msg` - Message content	`MessageHub`

Example:

// Quickly add a warning message
messageHub.warn("连接即将超时");

(Ⅱ) Extended Data and Directives

1. `extensions(Map<Object, Object> extensions)`

Description: Adds extended data in batches and stores it in dataExtension.extensions.
Parameter: extensions - Key-value extended data.
Return Value: MessageHub instance.

2. `extensions(Object key, Object value)`

Description: Adds a single piece of extended data.
Parameter: key - Key, value - Value.
Return Value: MessageHub instance.

3. `directives(Set<String> directives)` / `directives(String directive)`

Description: Adds front-end directives (such as page navigation, refresh, etc.) and stores them in dataExtension.directives.
Parameter: directives - Directive set or single directive.
Return Value: MessageHub instance.

(Ⅲ) Error Handling

1. `error(ExpBaseEnum error)`

Description: Adds an error message based on the enum, including the error code, type, and message.
Parameter: error - An enum instance implementing ExpBaseEnum (needs to provide msg(), code(), type()).
Return Value: MessageHub instance.

2. `fill(boolean success, ErrorExtension errorExtension)`

Description: Fills the error status and details, automatically handling message and status marking.
Parameter: success - Whether successful, errorExtension - Error extension information.
Return Value: MessageHub instance.

(Ⅳ) Execution Path

1. `appendPath(String segment)` / `appendPath(Integer segment)`

Description: Adds an execution path segment (string or integer, used for field positioning, such as name or array index).
Parameter: segment - Path segment.
Return Value: MessageHub instance.

Example:

// Set the error path for the field "name"
messageHub.appendPath("name");

(Ⅴ) Status Control

1. `error()`

Description: Marks the error status (success=false), without adding specific messages.
Return Value: MessageHub instance.

2. `clear()`

Description: Clears all messages and statuses, resetting success=true.
Return Value: MessageHub instance.

(Ⅵ) Data Acquisition

1. `getAllMessages()`

Description: Gets all messages (including data messages and error messages).
Return Value: List<Message>.

2. `getDataMessages()` / `getErrorMessages()`

Description: Gets the non-error message and error message lists, respectively.
Return Value: List<Message> (may be null).

Ⅴ、Message Levels (`InformationLevelEnum`)

Level	Description	Front-end Display Characteristics
`DEBUG`	Debug information	Usually hidden or displayed in light color (depends on front-end configuration).
`INFO`	General information	Prompt Toast or banner.
`SUCCESS`	Success notification	Green highlight, possibly with operation feedback.
`WARN`	Warning	Yellow highlight, prompting potential problems.
`ERROR`	Error	Red highlight, can interrupt the process (judged based on `success` ).

Front-end Display Rules:

Messages without field: Displayed globally via Toast, etc.
Messages with field: Displayed below the corresponding field (such as form validation errors).
Error message interruption logic: If success=false, only display the message without navigation; otherwise, display and navigate.

Ⅵ、Example Code

(Ⅰ) Form Validation Scenario

@Function
public Boolean checkData(TestConstraintsModel data) {
    String name = data.getName();
    boolean success = true;
    if (StringUtils.isBlank(name)) {
        PamirsSession.getMessageHub()
            .msg(Message.init()
                .setLevel(InformationLevelEnum.ERROR)
                .setField(LambdaUtil.fetchFieldName(TestConstraintsModel::getName))
                .setMessage("名称为必填项"));
        success = false;
    }
    if (name.length() > 4) {
        PamirsSession.getMessageHub()
            .msg(Message.init()
                .setLevel(InformationLevelEnum.ERROR)
                .setField(LambdaUtil.fetchFieldName(TestConstraintsModel::getName))
                .setMessage("名称过长，不能超过4位"));
        success = false;
    }
    return success;
}

Explanation: Validates the name field, adds field-level error messages, automatically marks success=false, and the front end displays errors below the name field.

(Ⅱ) Quickly Add a Success Message

messageHub.success("操作成功！")
          .directives("redirectToHome"); // Add front-end navigation directive

Ⅶ、Notes

Message Level Priority: ERROR-level messages will force success=false, and other levels do not affect success (unless error() is called explicitly).
Field Positioning: Set the field path through setField() or appendPath() to ensure the front end correctly locates the display position.
Performance: The closure(Supplier<T>) method is used to automatically clear the message center before and after code blocks to avoid cross-request message pollution.

Ⅷ、Class Diagram (Simplified)

MessageHub
├─ success: boolean
├─ dataExtension: DataExtension
├─ errorExtension: ErrorExtension
├─ path: ClientExecutionPath
├─ msg(Message): MessageHub
├─ info(String): MessageHub
├─ error(String): MessageHub
└─ clear(): MessageHub

Through the above documentation, developers can clearly understand the message management mechanism of MessageHub, the processing logic of each level of messages, and the front-end display rules, and quickly implement message transmission and status control in business.