FunctionDefContainer

Background and Use Cases

FanRuan Report provides a rich set of built-in functions for data processing. When built-in functions cannot meet specific business requirements, custom functions can be extended via plugin interfaces. There are two main extension approaches:

• AbstractFunction: Extends a single function
• FunctionDefContainer: Registers a group of business-related functions in bulk

When multiple related functions need to be extended under a specific business context, FunctionDefContainer is recommended for grouped management.

Interface Definition

package com.fr.stable.fun;

import com.fr.stable.fun.mark.Mutable;
import com.fr.stable.script.FunctionDef;

public interface FunctionDefContainer extends Mutable {
    int CURRENT_LEVEL = 1;
    String MARK_STRING = "FunctionGroup";

    FunctionDef[] getFunctionDefs();
    String getGroupName();
}

FunctionDef contains function name, description, and class name attributes, and supports XML serialization.

AbstractFunction is the abstract base class that implements the evalExpression() method to handle Node arguments, delegating to the abstract method run(Object[]) and handling error reporting.

Supported Versions

Plugin Registration

Add the following node in plugin.xml:

<extra-core>
    <FunctionGroup class="your class name"/>
</extra-core>

Note: The registration tag is <FunctionGroup>, which differs from the interface class name FunctionDefContainer (because MARK_STRING = "FunctionGroup").

How It Works

When the plugin loads, ExtraClassManager converts XML attributes into cached FunctionDef objects, completing function definition initialization. Functions are integrated into the calculation system by registering with DefaultNameSpace. The lookup priority is: built-in functions → custom extensions → single-function extensions → grouped function extensions.

Useful Links

• Demo: demo-function-def-container

Open Source Examples

Disclaimer: All open source examples in the documentation are developed and provided by developers for reference and learning purposes only. Developers and the official team have no obligation to provide instruction or guidance on open source examples. Commercial use is strictly prohibited; any consequences from commercial use are the sole responsibility of the user.

• demo-function-fibonacci
• open-JSD-7837
• open-JSD-7615