Master Easy Work: Build, Run, and Serialize Java Workflows with Code Examples

What is Easy Work?

Easy Work is a Java workflow engine that provides a concise API and modular components for building composable workflows.

In Easy Work, a work unit is represented by the Work interface and a workflow by the WorkFlow interface. The engine offers six implementations of WorkFlow (RepeatFlow, SequentialFlow, ParallelFlow, ConditionalFlow, etc.).

Creating a Simple Work

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;
    }
}

Defining a Composite Workflow

The example workflow consists of:

Repeat printing "a" three times.

Sequentially printing "b", "c", "d".

Parallel execution of "e" and "f".

Conditional execution: if the parallel step completes, run "g"; otherwise run "h".

Finally print "z".

The corresponding code uses the fluent API:

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());

Pausing a Workflow (Breakpoint)

Since version 1.0.5, Easy Work supports breakpoints that allow pausing execution at any work unit and later resuming.

Example: set a breakpoint on work unit c, execute up to that point, then continue.

SequentialFlow flow = aNewSequentialFlow(
    aNewRepeatFlow(a).times(3),
    aNewSequentialFlow(b, aNamePointWork(c).point("C_BREAK_POINT"), d),
    aNewConditionalFlow(
        aNewParallelFlow(e, f).withAutoShutDown(true)
    ).when(WorkReportPredicate.COMPLETED, g, h),
    z
);
flow.execute("C_BREAK_POINT"); // pause
System.out.println("execute to the break point `C_BREAK_POINT`");
flow.execute(); // resume

Building Workflows with JSON

From version 1.0.8, workflows can be defined in JSON. The following snippet represents the same workflow as 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"}
  ]
}

Deserialize and execute:

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

Rich Conditional Predicates

Easy Work includes a variety of built‑in Predicate implementations to simplify complex conditional logic.

PrintMessageWork ageEqualTen = new PrintMessageWork("age equal than 10");
PrintMessageWork ageLessThanTen = new PrintMessageWork("age less than 10");
UserPrintWork userWork = new UserPrintWork(new User().setAge(15).setName("john"));
aNewConditionalFlow(userWork)
    .when(
        andPredicate(
            aNewEqPredicate(WorkReport::getStatus, "COMPLETED"),
            aNewGreaterEqualPredicate("$result.$age", 10),
            aNewEqPredicate("$result", User::getName, "john")
        ),
        ageEqualTen,
        ageLessThanTen
    ).execute(new WorkContext());

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