Custom Extensions
erupt-flow supports custom flow nodes and global flow behavior — implement email notification, SMS sending, delayed waits, and more without any frontend code.
Custom Nodes
Flow nodes go far beyond approval and CC — delayed waits, email notifications, SMS sending, webhook calls, data sync… any business action can be packaged as a custom node. Once registered, it automatically appears in the flow designer's node palette, ready for business users to drag and drop just like a built-in node — a capability most workflow engines only offer by modifying the engine itself:
TIP
The form bound to a custom node is also an erupt class — the node's configuration UI is auto-rendered by erupt, no frontend development required.
Create a class extending FlexFlowProcess. The generic type is an erupt class defining the form bound to the node. A delay node as an example:
@Component
public class WaitNodeProcess extends FlexFlowProcess<WaitNode> {
@Resource
private EruptDao eruptDao;
// Node code
@Override
public String code() {
return "wait";
}
// Node name
@Override
public String name() {
return "Wait Node";
}
// Node color
@Override
public String color() {
return "#4CAF50";
}
// Node initialization logic
@Override
public String prepare(EruptFlowInstance flowInstance, NodeRule nodeRule, WaitNode waitNode) {
LocalDateTime finishDateTime = switch (waitNode.getWaitType()) {
case AFTER_MINUTES -> LocalDateTime.now().plusMinutes(waitNode.getInterval());
case AFTER_HOURS -> LocalDateTime.now().plusHours(waitNode.getInterval());
case AFTER_DAYS -> LocalDateTime.now().plusDays(waitNode.getInterval());
case CURRENT_DAY_TIME -> LocalDateTime.of(LocalDate.now(), LocalTime.parse(waitNode.getTime()));
case FIXED_TIME -> waitNode.getDatetime();
};
return finishDateTime.toString();
}
// Node evaluation logic: return Flow.await() to re-evaluate on the next flow check, Flow.next() to proceed
@Override
public Flow evaluate(String data, EruptFlowInstance flowInstance, NodeRule nodeRule, WaitNode waitNode) {
if (LocalDateTime.parse(data).isBefore(LocalDateTime.now())) {
return Flow.next();
} else {
return Flow.await();
}
}
}The node lifecycle works as follows — prepare() runs when the flow reaches the node, evaluate() is driven periodically by the scheduler, and returning Flow.next() moves on to the next node:
Definition of the form WaitNode bound to the node:
@Getter
@Setter
@Erupt(name = "Wait Node")
public class WaitNode extends BaseModel {
@EruptField(edit = @Edit(title = "Wait Type", notNull = true, type = EditType.CHOICE, choiceType = @ChoiceType(fetchHandler = WaitType.H.class)))
private WaitType waitType;
@EruptField(edit = @Edit(title = "Interval", dynamic = @Dynamic(
dependField = "waitType", condition = "value=='AFTER_MINUTES'||value=='AFTER_HOURS'||value=='AFTER_DAYS'"
)))
private Integer interval;
@EruptField(edit = @Edit(title = "Time of Day", dynamic = @Dynamic(
dependField = "waitType", condition = "value=='CURRENT_DAY_TIME'"),
type = EditType.DATE, dateType = @DateType(type = DateType.Type.TIME))
)
private String time;
@EruptField(edit = @Edit(title = "Fixed Date",
type = EditType.DATE,
dateType = @DateType(type = DateType.Type.DATE_TIME, pickerMode = DateType.PickerMode.FUTURE),
dynamic = @Dynamic(dependField = "waitType", condition = "value=='FIXED_TIME'")))
private LocalDateTime datetime;
}TIP
The field linkage above comes from @Dynamic: condition is a JS expression in which value holds the current value of dependField. @Dynamic defaults to match = Ctrl.SHOW and noMatch = Ctrl.HIDE, i.e. show when the condition matches and hide otherwise.
Customize Flow Behavior
Customize global flow logic such as flow number generation and notification delivery.
1. Create a global flow handler class extending EruptFlowProcess and override the relevant methods:
@Component
public class DemoFlowProcess extends EruptFlowProcess {
// Flow number generation logic
@Override
public String genFlowNo() {
return RandomStringUtils.randomAlphanumeric(8);
}
// Custom flow notification logic
@Override
public void notification(Long userId, String title, String content) {
super.notification(userId, title, content);
}
}2. Add the @EruptFlowManager annotation to the application entry class to activate it:
@SpringBootApplication
@EruptScan
@EruptFlowManager(DemoFlowProcess.class)
public class EruptDemoApplication {
public static void main(String[] args) {
SpringApplication.run(EruptDemoApplication.class, args);
}
}Contributors
YuePeng
Claude Fable 5.1