| Panel |
|---|
| borderStyle | solid |
|---|
| title | Table of contents |
|---|
|
|
Simple master-detail example
Working on my Wicket/databinder/Hibernate application I've run into a problem. How I can show master-detail relation entities extracted from the database? No doubt there are tens ways how to do this, but I wanted to exploit mature and convenient Hibernate's lazy loading facility and avoid code cluttering.
Say there is an Order entity list with list of its Items is shown in a master table. Order Items Set is a member, declared with Hibernate @OneToMany annotation, must be shown on neighbour table.
Entity Code
| Code Block |
|---|
|
@Entity
public class Order {
@Id Integer orderId;
@Column Integer number;
...
@OneToMany
Set<OrderItem> items;
...
}
@Entity
public class OrderItem {
@Id Integer itemId;
@Column String itemName;
...
}
|
Markup code
| Code Block |
|---|
| html |
|---|
| html |
|---|
| title | HomePage.html |
|---|
|
<html>
<body>
<table cellspacing="0" cellpadding="2" border="1">
<tr wicket:id="orders">
<td><span wicket:id="orderId">[order id]</span></td>
<td><a wicket:id="alink"><span wicket:id="number">[order number]</span></a></td>
</tr>
</table>
<div wicket:id="itemsWrap"></div>
</body>
</html>
|
| Code Block |
|---|
| html |
|---|
| html |
|---|
| title | HomePage$ItemsPanel.html |
|---|
|
<wicket:panel>
<table cellspacing="0" cellpadding="2" border="1">
<tr wicket:id="items">
<td><span wicket:id="itemId">[id]</span></td>
<td><span wicket:id="itemName">[name]</span></td>
</tr>
</table>
</wicket:panel>
|
Clicking on the link 'order number', left panel should be refreshed with the associated list of the order's item list. Of course it is a good idea to use an ajax-based refresh and Wicket good deal with such cases.
To be ended later...