chatgpt:实现流程节点迁移逻辑-查看文章

chatgpt:实现流程节点迁移逻辑

发表于:2023-05-06 14:29:06 分类:JAVA 阅读:241次

流程节点迁移逻辑的实现可以使用状态模式进行设计。下面是一个可能的实现:

首先,定义抽象流程节点类Node,其中包括节点名称和节点类型属性,以及相关操作方法。

public abstract class Node {
    protected String name;
    protected NodeType type;

    public Node(String name, NodeType type) {
        this.name = name;
        this.type = type;
    }

    public String getName() {
        return name;
    }

    public NodeType getType() {
        return type;
    }

    public abstract void enter(ProcessInstance instance);

    public abstract void execute(ProcessInstance instance);

    public abstract void exit(ProcessInstance instance);

    public enum NodeType {
        START,
        END,
        INTERMEDIATE
    }
}

根据不同的节点类型分别实现对应的具体节点类:StartNodeEndNodeIntermediateNode

public class StartNode extends Node {
    public StartNode(String name) {
        super(name, NodeType.START);
    }

    @Override
    public void enter(ProcessInstance instance) {
        // do nothing
    }

    @Override
    public void execute(ProcessInstance instance) {
        // transition to next node
        Node nextNode = instance.getNextNode(this);
        instance.setCurrentNode(nextNode);
        nextNode.enter(instance);
    }

    @Override
    public void exit(ProcessInstance instance) {
        // do nothing
    }
}

public class EndNode extends Node {
    public EndNode(String name) {
        super(name, NodeType.END);
    }

    @Override
    public void enter(ProcessInstance instance) {
        // do nothing
    }

    @Override
    public void execute(ProcessInstance instance) {
        // do nothing
    }

    @Override
    public void exit(ProcessInstance instance) {
        // do nothing
    }
}

public class IntermediateNode extends Node {
    private List<Node> outgoingNodes;

    public IntermediateNode(String name, List<Node> outgoingNodes) {
        super(name, NodeType.INTERMEDIATE);
        this.outgoingNodes = outgoingNodes;
    }

    public List<Node> getOutgoingNodes() {
        return outgoingNodes;
    }

    @Override
    public void enter(ProcessInstance instance) {
        // do nothing
    }

    @Override
    public void execute(ProcessInstance instance) {
        //transition to the next node based on process variables
        String transition = instance.getTransition();
        Node nextNode = outgoingNodes.stream()
                .filter(node -> node.getName().equals(transition))
                .findFirst()
                .orElseThrow(() -> new RuntimeException("Unable to find target node: " + transition));
        instance.setCurrentNode(nextNode);
        nextNode.enter(instance);
    }

    @Override
    public void exit(ProcessInstance instance) {
        // do nothing
    }
}

然后定义ProcessInstance类,其中包含当前节点和下一个节点属性,以及保存和获取这些属性的方法。start() 方法用于启动流程实例。

public class ProcessInstance {
    private Map<String, Object> processVariables;
    private Node currentNode;
    private Node nextNode;

    public ProcessInstance(Map<String, Object> processVariables, Node startNode) {
        this.processVariables = processVariables;
        this.currentNode = startNode;
    }

    public void start() {
        currentNode.enter(this);
        while (!(currentNode instanceof EndNode)) {
            currentNode.execute(this);
        }
        currentNode.exit(this);
    }

    public void setCurrentNode(Node node) {
        this.currentNode = node;
    }

    public Node getCurrentNode() {
        return currentNode;
    }

    public void setNextNode(Node node) {
        this.nextNode = node;
    }

    public Node getNextNode(Node currentNode) {
        List<Node> outgoingNodes = ((IntermediateNode) current).getOutgoingNodes();
        if (outgoingNodes.size() == 1) {
            return outgoingNodes.get(0);
        } else {
            // Find the next node based on process variables or other conditions
        }
    }

    public String getTransition() {
        //return the transition based on process variables or user input
    }

    public Map<String, Object> getProcessVariables() {
        return processVariables;
    }
}

使用示例:

List<Node> nodes = Arrays.asList(
        new StartNode("start"),
        new IntermediateNode("select_user", Arrays.asList(
                new IntermediateNode("assign_task", Arrays.asList(
                        new IntermediateNode("perform_task", Arrays.asList(
                                new IntermediateNode("review", Arrays.asList(
                                        new IntermediateNode("rework", Arrays.asList(
                                                new IntermediateNode("perform_task2", Arrays.asList(
                                                        new EndNode("end")
                                                ))
                                        )),
                                        new IntermediateNode("perform_task3", Arrays.asList(
                                                new EndNode("end")
                                        ))
                                ))
                        ))
                ))
        ))
);

Map<String, Object> processVariables = new HashMap<>();
processVariables.put("service_level", "VIP");

ProcessInstance instance = new ProcessInstance(processVariables, nodes.get(0));
instance.start();


关键词:java,bpm


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