/*
* Copyright (C) 2015 Red Hat, Inc. and/or its affiliates.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.jboss.errai.ui.nav.client.local;
import org.jboss.errai.ui.nav.client.local.api.NavigationControl;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* Indicates that the target method should be called when the {@link Page}
* it is a member of is about to be displayed in the navigation content
* panel: after the page's {@link PageState} fields have been updated and
* before it is displayed in the navigation content panel.
* <p>
* When the client-side application is bootstrapping (the page is loading in the
* browser), the Navigation system waits until all Errai modules are fully
* initialized before displaying the initial page. Hence, it is safe to make RPC
* requests and to fire portable CDI events from within a {@link PageShowing}
* method.
* <p>
* The target method is permitted an optional parameter of type
* {@link HistoryToken}. If the parameter is present, the framework will pass in
* the history token that caused the page to show. This is useful in cases where
* not all history token key names are known at compile time, so
* {@code @PageState} fields can't be declared to accept their values.
* <p>
* The target method is permitted an optional parameter of type {@link NavigationControl}. If the
* parameter is present, the page navigation will not be carried out until
* {@link NavigationControl#proceed()} is invoked. This is useful for redirecting navigation before
* a page has been displayed, based on asynchronous logic (for example, to redirect to another page
* based on the result of an Errai RPC).
* <p>
* Page loading can be interrupted by calling {@link NavigationControl#redirect(Class)}.
* This allows for page redirection rather than proceeding a pages navigation.
* The target method's return type must be {@code void}.
* <p>
* The target method can have any access type: public, protected, default, or
* private.
* <p>
* If the target method throws an exception when called, behaviour is undefined.
*
* @see Page
* @see PageState
* @see Navigation
* @see PageShown
* @author Jonathan Fuerth <jfuerth@redhat.com>
*/
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface PageShowing {
}