Vaadin, JPA, Spring - 具有组合主键的实体的简单形式

Question

I have simple database model, with ability to nest product categories, like this:

And I want to create basic form in Vaadin, that has two ComboBoxes to create this decomposed entity .

I cannot bind composed key that si constructed with @Embeddable and @EmbeddedId to my form fields .

When I click on button "Add category" which should bring up an empty form, I get this error :

java.lang.NullPointerException: null
    at java.base/java.lang.reflect.Method.invoke(Method.java:559) ~[na:na]
    at com.vaadin.flow.data.binder.BeanPropertySet.invokeWrapExceptions(BeanPropertySet.java:516) ~[flow-data-2.1.8.jar:2.1.8]
    at com.vaadin.flow.data.binder.BeanPropertySet.access$600(BeanPropertySet.java:48) ~[flow-data-2.1.8.jar:2.1.8]
    at com.vaadin.flow.data.binder.BeanPropertySet$NestedBeanPropertyDefinition.lambda$getGetter$3ec26976$1(BeanPropertySet.java:200) ~[flow-data-2.1.8.jar:2.1.8]
    at com.vaadin.flow.data.binder.Binder$BindingImpl.initFieldValue(Binder.java:1130) ~[flow-data-2.1.8.jar:2.1.8]
    at com.vaadin.flow.data.binder.Binder$BindingImpl.access$200(Binder.java:972) ~[flow-data-2.1.8.jar:2.1.8]
    at com.vaadin.flow.data.binder.Binder.lambda$setBean$1(Binder.java:1677) ~[flow-data-2.1.8.jar:2.1.8]
    at java.base/java.util.ArrayList.forEach(ArrayList.java:1540) ~[na:na]
    at com.vaadin.flow.data.binder.Binder.setBean(Binder.java:1677) ~[flow-data-2.1.8.jar:2.1.8]
    at cz.cvut.fit.manufacturingservices.ui.admin.view.product.category.ProductCategoryProductCategoryForm.setProductCategoryProductCategory(ProductCategoryProductCategoryForm.java:62) ~[main/:na]
    at cz.cvut.fit.manufacturingservices.ui.admin.view.product.category.ProductCategoryProductCategoryView.editProductCategoryProductCategory(ProductCategoryProductCategoryView.java:64) ~[main/:na]
    at cz.cvut.fit.manufacturingservices.ui.admin.view.product.category.ProductCategoryProductCategoryView.addProductCategoryProductCategory(ProductCategoryProductCategoryView.java:94) ~[main/:na]
    at cz.cvut.fit.manufacturingservices.ui.admin.view.product.category.ProductCategoryProductCategoryView.lambda$getToolbar$2f54d9f7$1(ProductCategoryProductCategoryView.java:78) ~[main/:na]
    at com.vaadin.flow.component.ComponentEventBus.fireEventForListener(ComponentEventBus.java:205) ~[flow-server-2.1.8.jar:2.1.8]
    at com.vaadin.flow.component.ComponentEventBus.handleDomEvent(ComponentEventBus.java:373) ~[flow-server-2.1.8.jar:2.1.8]
    at com.vaadin.flow.component.ComponentEventBus.lambda$addDomTrigger$dd1b7957$1(ComponentEventBus.java:264) ~[flow-server-2.1.8.jar:2.1.8]
    at com.vaadin.flow.internal.nodefeature.ElementListenerMap.lambda$fireEvent$2(ElementListenerMap.java:441) ~[flow-server-2.1.8.jar:2.1.8]
    at java.base/java.util.ArrayList.forEach(ArrayList.java:1540) ~[na:na]
    at com.vaadin.flow.internal.nodefeature.ElementListenerMap.fireEvent(ElementListenerMap.java:441) ~[flow-server-2.1.8.jar:2.1.8]
    at com.vaadin.flow.server.communication.rpc.EventRpcHandler.handleNode(EventRpcHandler.java:59) ~[flow-server-2.1.8.jar:2.1.8]
    at com.vaadin.flow.server.communication.rpc.AbstractRpcInvocationHandler.handle(AbstractRpcInvocationHandler.java:64) ~[flow-server-2.1.8.jar:2.1.8]
    at com.vaadin.flow.server.communication.ServerRpcHandler.handleInvocationData(ServerRpcHandler.java:409) ~[flow-server-2.1.8.jar:2.1.8]
    at com.vaadin.flow.server.communication.ServerRpcHandler.lambda$handleInvocations$1(ServerRpcHandler.java:390) ~[flow-server-2.1.8.jar:2.1.8]
    at java.base/java.util.ArrayList.forEach(ArrayList.java:1540) ~[na:na]
    at com.vaadin.flow.server.communication.ServerRpcHandler.handleInvocations(ServerRpcHandler.java:390) ~[flow-server-2.1.8.jar:2.1.8]
    at com.vaadin.flow.server.communication.ServerRpcHandler.handleRpc(ServerRpcHandler.java:317) ~[flow-server-2.1.8.jar:2.1.8]
    at com.vaadin.flow.server.communication.UidlRequestHandler.synchronizedHandleRequest(UidlRequestHandler.java:89) ~[flow-server-2.1.8.jar:2.1.8]
    at com.vaadin.flow.server.SynchronizedRequestHandler.handleRequest(SynchronizedRequestHandler.java:40) ~[flow-server-2.1.8.jar:2.1.8]
    at com.vaadin.flow.server.VaadinService.handleRequest(VaadinService.java:1540) ~[flow-server-2.1.8.jar:2.1.8]
    at com.vaadin.flow.server.VaadinServlet.service(VaadinServlet.java:247) ~[flow-server-2.1.8.jar:2.1.8]
    at com.vaadin.flow.spring.SpringServlet.service(SpringServlet.java:120) ~[vaadin-spring-12.1.4.jar:na]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:712) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:459) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:352) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:312) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.springframework.web.servlet.mvc.ServletForwardingController.handleRequestInternal(ServletForwardingController.java:141) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.web.servlet.mvc.AbstractController.handleRequest(AbstractController.java:177) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:52) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:909) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:660) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.33.jar:9.0.33]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:373) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1594) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) ~[na:na]
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) ~[na:na]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) ~[tomcat-embed-core-9.0.33.jar:9.0.33]
    at java.base/java.lang.Thread.run(Thread.java:834) ~[na:na]

My composte key implmentation:

@Embeddable
public class ProductCategoryProductCategoryIdentity implements Serializable {

    @ManyToOne(fetch = FetchType.EAGER)
    @JoinColumn(name = "product_category_parent_id", nullable = false)
    private ProductCategory productCategoryParent;

    @ManyToOne(fetch = FetchType.EAGER)
    @JoinColumn(name = "product_category_child_id", nullable = false)
    private ProductCategory productCategoryChild;

    public ProductCategory getProductCategoryParent() {
        return productCategoryParent;
    }

    public void setProductCategoryParent(ProductCategory productCategoryParent) {
        this.productCategoryParent = productCategoryParent;
    }

    public ProductCategory getProductCategoryChild() {
        return productCategoryChild;
    }

    public void setProductCategoryChild(ProductCategory productCategoryChild) {
        this.productCategoryChild = productCategoryChild;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (!(o instanceof ProductCategoryProductCategoryIdentity)) return false;
        ProductCategoryProductCategoryIdentity that = (ProductCategoryProductCategoryIdentity) o;
        return Objects.equals(getProductCategoryParent(), that.getProductCategoryParent()) &&
                Objects.equals(getProductCategoryChild(), that.getProductCategoryChild());
    }

    @Override
    public int hashCode() {
        return Objects.hash(getProductCategoryParent(), getProductCategoryChild());
    }
}

Repository implmentation:

public interface ProductCategoryProductCategoryRepository extends JpaRepository<ProductCategoryProductCategory, ProductCategoryProductCategoryIdentity> {
}

Service implementation:

@Service
public class ProductCategoryProductCategoryService {

    private static final Logger LOGGER = Logger.getLogger(ProductCategoryProductCategory.class.getName());

    @Autowired
    private ProductCategoryProductCategoryRepository productCategoryProductCategoryRepository;

    public List<ProductCategoryProductCategory> findAll() {
        return productCategoryProductCategoryRepository.findAll();
    }

    public void save(ProductCategoryProductCategory productCategoryProductCategory) {
        if (productCategoryProductCategory == null) {
            LOGGER.log(Level.SEVERE, "Cannot save null product category decomposition");
            return;
        }
        productCategoryProductCategoryRepository.save(productCategoryProductCategory);
    }
}

Form component implementation:

public class ProductCategoryProductCategoryForm extends FormLayout {
    ComboBox<ProductCategory> productCategoryParent = new ComboBox<>("Parent product category");
    ComboBox<ProductCategory> productCategoryChild = new ComboBox<>("Child product category");

    Button save = new Button("Save");
    Button close = new Button("Close");

    Binder<ProductCategoryProductCategory> binder = new BeanValidationBinder<>(ProductCategoryProductCategory.class);

    public ProductCategoryProductCategoryForm(List<ProductCategory> productCategories) {
        addClassName("product_category-form");

        productCategoryParent.setItems(productCategories);
        productCategoryParent.setItemLabelGenerator(ProductCategory::getLabel);
        productCategoryChild.setItems(productCategories);
        productCategoryChild.setItemLabelGenerator(ProductCategory::getLabel);

        //binder.bind(productCategoryParent, "id.productCategoryParent");
        //binder.bind(productCategoryChild, "id.productCategoryChild");

        //binder.bindInstanceFields(this);
        add(productCategoryParent, productCategoryChild, createButtonsLayout());
    }


    private Component createButtonsLayout() {
        save.addThemeVariants(ButtonVariant.LUMO_PRIMARY);
        close.addThemeVariants(ButtonVariant.LUMO_TERTIARY);

        save.addClickShortcut(Key.ENTER);
        close.addClickShortcut(Key.ESCAPE);

        save.addClickListener(event -> validateAndSave());
        close.addClickListener(event -> fireEvent(new CloseEvent(this)));

        binder.addStatusChangeListener(e -> save.setEnabled(binder.isValid()));

        return new HorizontalLayout(save, close);
    }

    public void setProductCategoryProductCategory(ProductCategoryProductCategory productCategoryProductCategory) {
        binder.setBean(productCategoryProductCategory);
    }

    private void validateAndSave() {
        if (binder.isValid()) {
            fireEvent(new SaveEvent(this, binder.getBean()));
        }
    }


    public static abstract class ProductCategoryProductCategoryFormEvent extends ComponentEvent<ProductCategoryProductCategoryForm> {
        private final ProductCategoryProductCategory productCategoryProductCategory;

        protected ProductCategoryProductCategoryFormEvent(ProductCategoryProductCategoryForm source, ProductCategoryProductCategory productCategoryProductCategory) {
            super(source, false);
            this.productCategoryProductCategory = productCategoryProductCategory;
        }

        public ProductCategoryProductCategory getProductCategoryProductCategory() {
            return productCategoryProductCategory;
        }
    }

    public static class SaveEvent extends ProductCategoryProductCategoryForm.ProductCategoryProductCategoryFormEvent {
        SaveEvent(ProductCategoryProductCategoryForm source, ProductCategoryProductCategory productCategoryProductCategory) {
            super(source, productCategoryProductCategory);
        }
    }

    public static class DeleteEvent extends ProductCategoryProductCategoryForm.ProductCategoryProductCategoryFormEvent {
        DeleteEvent(ProductCategoryProductCategoryForm source, ProductCategoryProductCategory productCategoryProductCategory) {
            super(source, productCategoryProductCategory);
        }

    }

    public static class CloseEvent extends ProductCategoryProductCategoryForm.ProductCategoryProductCategoryFormEvent {
        CloseEvent(ProductCategoryProductCategoryForm source) {
            super(source, null);
        }
    }

    public <T extends ComponentEvent<?>> Registration addListener(Class<T> eventType, ComponentEventListener<T> listener) {
        return getEventBus().addListener(eventType, listener);
    }
}

View implementation:

@Route(value = "product-category-product-category", layout = MainLayout.class)
public class ProductCategoryProductCategoryView extends VerticalLayout {

    private final Grid<ProductCategoryProductCategory> grid = new Grid<>(ProductCategoryProductCategory.class);
    private final ProductCategoryProductCategoryForm form;

    @Autowired
    private ProductCategoryProductCategoryService productCategoryProductCategoryService;

    public ProductCategoryProductCategoryView(ProductCategoryService productCategoryService) {
        form = new ProductCategoryProductCategoryForm(productCategoryService.findAll());
    }

    @PostConstruct
    public void init() {
        addClassName("product_category-view");
        setSizeFull();

        configureGrid();
        configureForm();

        add(getToolbar(), getContent());

        updateList();
        closeEditor();
    }

    private void configureForm() {
        form.addListener(ProductCategoryProductCategoryForm.SaveEvent.class, this::saveProductCategoryProductCategory);
        form.addListener(ProductCategoryProductCategoryForm.CloseEvent.class, e -> closeEditor());
    }

    private void configureGrid() {
        grid.addClassName("product_category-grid");
        grid.setSizeFull();

        //grid.setColumns("parentId", "childId");

        grid.asSingleSelect().addValueChangeListener(evn -> editProductCategoryProductCategory(evn.getValue()));
    }

    private void editProductCategoryProductCategory(ProductCategoryProductCategory productCategoryProductCategory) {
        if (productCategoryProductCategory == null)
            closeEditor();
        else {
            form.setProductCategoryProductCategory(productCategoryProductCategory);
            form.setVisible(true);
            addClassName("editing");
        }
    }

    private void closeEditor() {
        form.setProductCategoryProductCategory(null);
        form.setVisible(false);
        removeClassName("editing");
    }

    private HorizontalLayout getToolbar() {
        Button addProductCategoryButton = new Button("Add category");
        addProductCategoryButton.addClickListener(click -> addProductCategoryProductCategory());

        HorizontalLayout toolbar = new HorizontalLayout(addProductCategoryButton);
        toolbar.addClassName("toolbar");
        return toolbar;
    }

    private Component getContent() {
        Div content = new Div(grid, form);
        content.setSizeFull();
        content.addClassName("content");
        return content;
    }

    private void addProductCategoryProductCategory() {
        grid.asSingleSelect().clear();
        editProductCategoryProductCategory(new ProductCategoryProductCategory());
    }

    private void updateList() {
        grid.setItems(productCategoryProductCategoryService.findAll());
    }

    private void saveProductCategoryProductCategory(ProductCategoryProductCategoryForm.SaveEvent event) {
        productCategoryProductCategoryService.save(event.getProductCategoryProductCategory());
        updateList();
        closeEditor();
    }
}

Could you help me solve it or provide me simple entity with composed primary (foreign) key together with simple form to create that entity?

Thank you very much.

Answer 1

The error log says that there was a NullPointerException while trying to access a bound attribute of the ProductCategoryProductCategory instance during binder::setBean . I guess its the embeddable id thats null (without reading all the code), but you should either initialize the object with all needed values before binding, or check for null value of item.getId() in the binding.

Because you have a nested property bound, I think you need to declare the binding not via property-string, so you can add null-checks for item.getId() before calling item.getId().getProductCategoryParent() or its setter respectively.

binder.forField(productCategoryParent)
    .bind(                      // but if the id itself is null, don't try to get its parent
        (item) -> item.getId() == null ? null : item.getId().getProductCategoryParent(), 
        (item, value) -> {
            if(item.getId() != null){
                item.getId().setProductCategoryParent(value);
            }
        }
);

edit: removed mentioning of nullRepresentation as its a combobox and not a textfield. If the productCategoryParent were null, it would work, but its the ProductCategoryProductCategoryIdentity that is null.