Master Easy Work: Build and Control Java Workflows with Code, Breakpoints, and JSON

Overview

Easy Work is a lightweight Java workflow engine. It defines a Work interface for a single unit of work and a WorkFlow interface for a composition of works. Six built‑in workflow implementations are provided: RepeatFlow, SequentialFlow, ParallelFlow, ConditionalFlow, plus additional helpers.

Creating a Work

Implement the Work interface and override String execute(WorkContext). Example:

public class PrintMessageWork implements Work {
    private final String message;
    public PrintMessageWork(String message) { this.message = message; }
    @Override
    public String execute(WorkContext workContext) {
        System.out.println(message);
        return message;
    }
}

Composing a Workflow

Using the fluent factory methods the example workflow performs:

Repeat work “a” three times.

Sequentially print “b”, “c”, “d”.

Execute “e” and “f” in parallel, automatically shutting down the parallel executor when the branch finishes.

Based on the parallel result (predicate WorkReportPredicate.COMPLETED) run “g” if successful, otherwise “h”.

Finally run “z”.

Code:

PrintMessageWork a = new PrintMessageWork("a");
PrintMessageWork b = new PrintMessageWork("b");
PrintMessageWork c = new PrintMessageWork("c");
PrintMessageWork d = new PrintMessageWork("d");
PrintMessageWork e = new PrintMessageWork("e");
PrintMessageWork f = new PrintMessageWork("f");
PrintMessageWork g = new PrintMessageWork("g");
PrintMessageWork h = new PrintMessageWork("h");
PrintMessageWork z = new PrintMessageWork("z");

WorkFlow flow = aNewSequentialFlow(
    aNewRepeatFlow(a).times(3),
    aNewSequentialFlow(b, c, d),
    aNewConditionalFlow(
        aNewParallelFlow(e, f).withAutoShutDown(true)
    ).when(WorkReportPredicate.COMPLETED, g, h),
    z
);
aNewWorkFlowEngine().run(flow, new WorkContext());

Pause and Resume (Breakpoints)

Since version 1.0.5 the engine supports breakpoints. A breakpoint can be set on any work unit by name. Execution stops at the breakpoint, allowing external processing, and can be resumed later.

// pause at work identified by "C_BREAK_POINT"
flow.execute("C_BREAK_POINT");
System.out.println("paused at C_BREAK_POINT");

// resume execution until the workflow finishes
flow.execute();

JSON‑Based Workflow Definition

From version 1.0.8 a workflow can be described in JSON and deserialized at runtime. The same example expressed in JSON:

{
  "type":"sequential",
  "works":[
    {"type":"repeat","times":3,"work":{"type":"work.PrintMessageWork","message":"a"}},
    {"type":"sequential","works":[
        {"type":"work.PrintMessageWork","message":"b"},
        {"type":"work.PrintMessageWork","message":"c"},
        {"type":"work.PrintMessageWork","message":"d"}
    ]},
    {"type":"conditional","decide":{
        "type":"parallel",
        "autoShutdown":true,
        "works":[
            {"type":"work.PrintMessageWork","message":"e"},
            {"type":"work.PrintMessageWork","message":"f"}
        ]},
     "predicate":{"left":"$status","operator":"eq","right":"COMPLETED"},
     "trueWork":{"type":"work.PrintMessageWork","message":"g"},
     "falseWork":{"type":"work.PrintMessageWork","message":"h"}
    },
    {"type":"work.PrintMessageWork","message":"z"}
  ]
}

Deserialization and execution:

String json = ResourceReader.readJSON("json/example.json");
SequentialFlow sequentialFlow = (SequentialFlow) deserialize(json);
sequentialFlow.execute(new WorkContext());

Repository

The source code, test cases and documentation are hosted at:

https://gitee.com/ifrog/easy-work