Master Workflow Orchestration to Simplify Business Logic with Flow Engines

As a good programmer, keep solutions simple and avoid over‑design. I once dismissed workflow orchestration as unnecessary, but working in a middle‑platform team showed its importance for isolating business logic.

When many business lines share a system, adding new features without a workflow engine leads to tangled if‑else code, making maintenance risky and testing impossible.

The main pain points are code isolation and extensibility. Two practical solutions are:

Use a workflow engine to configure separate execution chains for each business scenario.

Use a plugin‑extension engine so each business can implement its own variations.

MemberClub demonstrates extensive use of a workflow engine and plugin‑extension engine to solve these problems.

Configuring the Execution Chain

DemoMemberPurchaseExtension shows how to define three different execution chain configurations for various member products.

Defining Flow Nodes

Each node implements process, success, rollback, and callback methods.

Executing the Flow

Call FlowChain.execute with a context object to run the chain.

During execution, nodes are linked like a responsibility chain: process runs sequentially, on exception rollback runs, and after all succeed success runs in reverse order, followed by callback.

FlowChain.execute Implementation

public <T> void execute(FlowChain<T> chain, T context) {
    Exception exception = null;
    int index = -1;
    for (FlowNode<T> node : chain.getNodes()) {
        try {
            node.process(context);
            index++;
        } catch (Exception e) {
            if (e instanceof SkipException) {
                CommonLog.warn("Current flow:{} sent Skip request, stop later flows", node.getClass().getSimpleName());
                break;
            }
            exception = e;
            break;
        }
    }

    if (exception != null) {
        for (int i = index; i >= 0; i--) {
            FlowNode<T> node = chain.getNodes().get(i);
            try {
                node.rollback(context, exception);
            } catch (Exception e) {
                CommonLog.error("rollback execution exception, ignore name:{}", node.getClass().getSimpleName(), e);
            }
        }
    } else {
        for (int i = index; i >= 0; i--) {
            FlowNode<T> node = chain.getNodes().get(i);
            try {
                node.success(context);
            } catch (Exception e) {
                CommonLog.error("success execution exception, ignore name:{}", node.getClass().getSimpleName(), e);
            }
        }
    }

    for (int i = index; i >= 0; i--) {
        FlowNode<T> node = chain.getNodes().get(i);
        try {
            node.callback(context, exception);
        } catch (Exception e) {
            CommonLog.error("callback execution exception, ignore name:{}", node.getClass().getSimpleName(), e);
        }
    }
    if (exception != null) {
        throw exception;
    }
}

Project Source

Source code: https://gitee.com/juejinwuyang/memberclub