| // Copyright 2006, 2007, 2008 The Apache Software Foundation |
| // |
| // 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.apache.tapestry5.annotations; |
| |
| import org.apache.tapestry5.EventConstants; |
| |
| import java.lang.annotation.Documented; |
| import java.lang.annotation.ElementType; |
| import java.lang.annotation.Retention; |
| import static java.lang.annotation.RetentionPolicy.RUNTIME; |
| import java.lang.annotation.Target; |
| |
| /** |
| * Marks a method as a handler for a client side event. The handler method will be invoked when a component triggers an |
| * event. Filters on the type of event and on the originating component ensure that only the appropriate methods are |
| * invoked. |
| * <p/> |
| * Client events include a <em>context</em> of one or more values. These context values are included in the action URI. |
| * The values are optionally supplied to the handler method as parameters. Automatic {@linkplain |
| * org.apache.tapestry5.ValueEncoder conversion} from string to the type of the actual parameter occur. |
| * <p/> |
| * Handlers may return a value. Returning a non-null value will abort the handling of the event, and will usually |
| * control the response sent to the client web browser. The details are somewhat specific to the type of event and the |
| * component involved. |
| * <p/> |
| * If a handler is not found within the originating component (or no handler aborts the event handling), then handlers |
| * within the containing component will be searched. This continues up the page hierarchy. In some cases, having no |
| * handlers (or no aborting handlers) is considered acceptible; in others, it is an error. Again, this is defined by the |
| * type of originating component, and the type of event. |
| * <p/> |
| * <strong>If you fail to provide filters on either component or event type, then your method will be invoked for all |
| * component events, possibly including events that bubble up from embedded sub-components. </strong> |
| */ |
| @Target(ElementType.METHOD) |
| @Retention(RUNTIME) |
| @Documented |
| public @interface OnEvent |
| { |
| |
| /** |
| * The event type to match. The handler will only be invoked if the client event type matches the value. The default |
| * value is "action". Matching is case-insensitive. |
| * |
| * @see org.apache.tapestry5.EventConstants |
| */ |
| String value() default EventConstants.ACTION; |
| |
| /** |
| * The local id of the component from which the event originates. If not specified, then the default is to match any |
| * component. If an event from a component is not handled in the component's container, it is re-triggered inside |
| * the component's grand-container and will appear to originate from the container. Thus events that escape a |
| * component will appear to originate in the component's container, and so forth. |
| * <p/> |
| * <p/> |
| * Matching by component id is case insensitive. |
| */ |
| String component() default ""; |
| |
| } |