使用JPAcontainer时,如何在Vaadin表中创建新的内联项?

时间:2013-07-10 17:52:20

标签: jpa vaadin

我正在使用Vaadin为单个数据库表构建一个简单的编辑器,使用JPAContainer和Vaadin Table组件。删除和编辑项目工作正常,但我在添加项目时遇到问题。

Vaadin教程解释了如何使用弹出窗口添加项目,但我想通过在表格中使用新的空行来添加项目。所需的功能是为用户提供一行默认数据,然后允许用户在对新行中的数据感到满意后保存数据。

我遇到的问题是,当我尝试做我认为应该工作的事情时,我得到UnsupportedOperation。

我的表已设置并绑定到位置实体的JPAContainer:

private JPAContainer locations = JPAContainerFactory.make(Location.class,PERSISTENCE_UNIT);

我将表设置为缓冲,因此在用户单击保存按钮之前,我不会将数据保存到数据库:

    locationTable = new Table(null,locations);
    locationTable.setVisibleColumns(new Object[]{ "id","x","y","z","createDate","lastModDate"  } );
    locationTable.setSelectable(true);
    locationTable.setSizeFull();
    locationTable.setImmediate(true);
    locationTable.setBuffered(true);
    locationTable.setVisible(true);
    locationTable.setEditable(true);

..保存按钮保存对数据库的更改:

    Button saveButton = new Button("Save Changes");
    saveButton.addClickListener(new Button.ClickListener() {
        public void buttonClick(ClickEvent event) {
            locations.commit();
            statusLabel.setCaption("Changes Saved");
        }
    });

然后我绑定了一个尝试添加新按钮的按钮。

    Button addButton = new Button("Add An Item");
    addButton.addClickListener(new Button.ClickListener() {
        public void buttonClick(ClickEvent event) {

            Object newkey = locationTable.addItem(new Object[]{"NEWLOCATION","0","0","0","7/10/2013","7/10/2013"}, "NEWLOCATION");
            locationTable.select(newkey);
            statusLabel.setCaption("Item Added. Populate Data and click Save to make permanent.");
        }
    });

单击additem按钮会抛出UnSupportedOperationException。

我试过调用addItem的其他变种,但我无法工作。有人知道如何通过在表中使用新行来在表中创建新项目吗?

完成init()源:

@Override
protected void init(VaadinRequest request) {

    final VerticalLayout layout = new VerticalLayout();
    layout.setMargin(true);
    setContent(layout);
    final Label statusLabel = new Label("");

    locationTable = new Table(null,locations);
    locationTable.setVisibleColumns(new Object[]{ "id","x","y","z","createDate","lastModDate"  } );
    locationTable.setSelectable(true);
    locationTable.setSizeFull();
    locationTable.setImmediate(true);
    locationTable.setBuffered(true);
    locationTable.setVisible(true);
    locationTable.setEditable(true);

    Button saveButton = new Button("Save Changes");
    saveButton.addClickListener(new Button.ClickListener() {
        public void buttonClick(ClickEvent event) {
            locations.commit();
            statusLabel.setCaption("Changes Saved");
        }
    });

    Button addButton = new Button("Add An Item");
    addButton.addClickListener(new Button.ClickListener() {
        public void buttonClick(ClickEvent event) {

            Object newkey = locationTable.addItem(new Object[]{"NEWLOCATION","0","0","0","7/10/2013","7/10/2013"}, "NEWLOCATION");
            locationTable.select(newkey);
            statusLabel.setCaption("Item Added. Populate Data and click Save to make permanent.");
        }
    });
    Button deleteButton = new Button("Delete Selected");
    deleteButton.addClickListener(new Button.ClickListener() {
        public void buttonClick(ClickEvent event) {
             locations.removeItem(locationTable.getValue());
             statusLabel.setCaption("Item Removed. Click Save to make permanent.");
        }
    });


    layout.addComponent(locationTable );
    layout.addComponent(saveButton);
    layout.addComponent(addButton);
    layout.addComponent(deleteButton);
    layout.addComponent(statusLabel);



}

1 个答案:

答案 0 :(得分:0)

好的,由于Vaadin JPA容器的限制,可以执行我之后的操作,但仅限于具有自动生成主键的实体。 我使用自动生成的id按预期工作的代码,但如果不是这样,则会失败。

向容器添加新项时,com.vaadin.ui.Table委托给它的容器,在没有提供itemId的情况下调用.addItem(),或者在提供的情况下调用getItem()。 / p>

对于新项目,调用.addItem():

/**
 * <strong>This functionality is not fully supported by this
 * implementation.</strong> The implementation tries to call empty parameter
 * constructor and add entity as such to database. If identifiers are not
 * autogenerated or empty parameter constructor does not exist, the
 * operation will fail and throw UnSupportedOperationException.
 * <p>
 * {@inheritDoc }
 */
public Object addItem() throws UnsupportedOperationException {
    try {
        T newInstance = getEntityClass().newInstance();
        Object id = addEntity(newInstance);
        return id;
    } catch (InstantiationException e) {
    } catch (IllegalAccessException e) {
    }
    throw new UnsupportedOperationException();
}

此代码解释了问题 - 如果无法在数据库中使用null contstructor创建实体,则会失败。

Vaadin示例通过使用Form对象来收集数据,然后在完全填充数据之后调用addEntity()方法。