Package org.dellroad.stuff.vaadin7

Annotation Type ProvidesProperty

@Retention(RUNTIME)
@Target({METHOD,FIELD})
@Documented
public @interface ProvidesProperty

Declares that a Java method provides a read-only Vaadin Property value in a Java class whose instances back the items in a Container.

@ProvidesProperty and @ProvidesPropertySort method annotations can be used to automatically generate a list of PropertyDefs and a PropertyExtractor using a ProvidesPropertyScanner. This happens automatically when using the appropriate constructors of the various Container classes in this package.

This annotation indicates that a read-only Vaadin Property having the specified name and type derived from the method's return value is accessible by reading that method. Annotated methods must have zero parameters.

For example:

 // Container backing object class
 public class User {

     public static final String USERNAME_PROPERTY = "username";
     public static final String REAL_NAME_PROPERTY = "realName";

     private String username;
     private String realName;

     public String getUsername() {
         return this.username;
     }
     public void setUsername(String username) {
         this.username = username;
     }

     @ProvidesProperty                     // property name "realName" is implied by method name
     public String getRealName() {
         return this.realName;
     }
     public void setRealName(String realName) {
         this.realName = realName;
     }

     @ProvidesProperty(USERNAME_PROPERTY)  // display usernames in fixed-width font
     private Label usernameProperty() {
         return new Label("<code>" + StringUtil.escapeHtml(this.username) + "</code>", ContentMode.HTML);
     }
 }

 // User container class
 public class UserContainer extends SimpleKeyedContainer<String, User> {

     public UserContainer() {
         super(User.class);
     }

     @Override
     public String getKeyFor(User user) {
         return user.getUsername();
     }
 }

 // Create container holding all users
 UserContainer container = new UserContainer();
 container.load(this.userDAO.getAllUsers());

 // Build table showing users
 Table table = new Table();
 table.setColumnHeader(User.USERNAME_PROPERTY, "User");
 table.setColumnHeader(User.REAL_NAME_PROPERTY, "Name");
 table.setVisibleColumns(User.USERNAME_PROPERTY, User.REAL_NAME_PROPERTY);

 // Select user "jsmith" in the table
 table.setValue("jsmith");
 ...
 

Some details regarding @ProvidesProperty annotations on methods:

• Only non-void methods taking zero parameters are supported; @ProvidesProperty annotations on other methods are ignored
• Protected, package private, and private methods are supported.
• @ProvidesProperty annotations on interface methods are supported
• If a method and the superclass or superinterface method it overrides are both annotated with @ProvidesProperty, then the overridding method's annotation takes precedence.
• If two methods with different names are annotated with @ProvidesProperty for the same property name, then the declaration in the class which is a sub-type of the other wins (if the two methods are delcared in the same class, an exception is thrown). This allows subclasses to "override" which method supplies a given property.

To control how properties are sorted (e.g., in tables), see @ProvidesPropertySort.

See Also:

ProvidesPropertySort, ProvidesPropertyScanner

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element	Description
String	value	Get the name of the Vaadin property.

Element Detail

value

String value

Get the name of the Vaadin property. If this is left unset (empty string), then the bean property name of the annotated bean property "getter" method is used.

Returns:

property name

Default:

""