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Diffstat (limited to 'src/com/vaadin/shared/ui/Connect.java')
-rw-r--r-- | src/com/vaadin/shared/ui/Connect.java | 93 |
1 files changed, 93 insertions, 0 deletions
diff --git a/src/com/vaadin/shared/ui/Connect.java b/src/com/vaadin/shared/ui/Connect.java new file mode 100644 index 0000000000..aa60096eb9 --- /dev/null +++ b/src/com/vaadin/shared/ui/Connect.java @@ -0,0 +1,93 @@ +/* +@VaadinApache2LicenseForJavaFiles@ + */ +package com.vaadin.shared.ui; + +import java.lang.annotation.ElementType; +import java.lang.annotation.Retention; +import java.lang.annotation.RetentionPolicy; +import java.lang.annotation.Target; + +import com.vaadin.shared.Connector; +import com.vaadin.terminal.gwt.server.ClientConnector; +import com.vaadin.terminal.gwt.widgetsetutils.CustomWidgetMapGenerator; +import com.vaadin.terminal.gwt.widgetsetutils.EagerWidgetMapGenerator; +import com.vaadin.terminal.gwt.widgetsetutils.LazyWidgetMapGenerator; +import com.vaadin.terminal.gwt.widgetsetutils.WidgetMapGenerator; + +/** + * Annotation defining the server side connector that this ClientSideConnector + * should connect to. The value must always by a class extending + * {@link ClientConnector}. + * <p> + * With this annotation client side Vaadin connector is marked to have a server + * side counterpart. The value of the annotation is the class of server side + * implementation. + * + * @since 7.0 + */ +@Retention(RetentionPolicy.RUNTIME) +@Target(ElementType.TYPE) +public @interface Connect { + + /** + * @return the server side counterpart for the annotated component connector + */ + Class<? extends Connector> value(); + + /** + * Depending on the used WidgetMap generator, these optional hints may be + * used to define how the client side components are loaded by the browser. + * The default is to eagerly load all widgets + * {@link EagerWidgetMapGenerator}, but if the {@link WidgetMapGenerator} is + * used by the widgetset, these load style hints are respected. + * <p> + * Lazy loading of a widget implementation means the client side component + * is not included in the initial JavaScript application loaded when the + * application starts. Instead the implementation is loaded to the client + * when it is first needed. Lazy loaded widget can be achieved by giving + * {@link LoadStyle#LAZY} value in {@link Connect} annotation. + * <p> + * Lazy loaded widgets don't stress the size and startup time of the client + * side as much as eagerly loaded widgets. On the other hand there is a + * slight latency when lazy loaded widgets are first used as the client side + * needs to visit the server to fetch the client side implementation. + * <p> + * The {@link LoadStyle#DEFERRED} will also not stress the initially loaded + * JavaScript file. If this load style is defined, the widget implementation + * is preemptively loaded to the browser after the application is started + * and the communication to server idles. This load style kind of combines + * the best of both worlds. + * <p> + * Fine tunings to widget loading can also be made by overriding + * {@link WidgetMapGenerator} in the GWT module. Tunings might be helpful if + * the end users have slow connections and especially if they have high + * latency in their network. The {@link CustomWidgetMapGenerator} is an + * abstract generator implementation for easy customization. Vaadin package + * also includes {@link LazyWidgetMapGenerator} that makes as many widgets + * lazily loaded as possible. + * + * @since 6.4 + * + * @return the hint for the widget set generator how the client side + * implementation should be loaded to the browser + */ + LoadStyle loadStyle() default LoadStyle.DEFERRED; + + public enum LoadStyle { + /** + * The widget is included in the initial JS sent to the client. + */ + EAGER, + /** + * Not included in the initial set of widgets, but added to queue from + * which it will be loaded when network is not busy or the + * implementation is required. + */ + DEFERRED, + /** + * Loaded to the client only if needed. + */ + LAZY + } +} |