001// Copyright 2006, 2007, 2009 The Apache Software Foundation
002//
003// Licensed under the Apache License, Version 2.0 (the "License");
004// you may not use this file except in compliance with the License.
005// You may obtain a copy of the License at
006//
007//     http://www.apache.org/licenses/LICENSE-2.0
008//
009// Unless required by applicable law or agreed to in writing, software
010// distributed under the License is distributed on an "AS IS" BASIS,
011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012// See the License for the specific language governing permissions and
013// limitations under the License.
014
015package org.apache.tapestry5.annotations;
016
017import java.lang.annotation.Documented;
018import static java.lang.annotation.ElementType.FIELD;
019import java.lang.annotation.Retention;
020import static java.lang.annotation.RetentionPolicy.RUNTIME;
021import java.lang.annotation.Target;
022
023import static org.apache.tapestry5.ioc.annotations.AnnotationUseContext.COMPONENT;
024import org.apache.tapestry5.ioc.annotations.UseWith;
025
026/**
027 * Defines an <em>implementation</em> mixin for a component.
028 */
029@Target(FIELD)
030@Documented
031@Retention(RUNTIME)
032@UseWith({COMPONENT})
033public @interface Mixin
034{
035
036    /**
037     * Defines the type of mixin, using a logical mixin name. This value takes precedence over the type of field (to
038     * which the annotation is attached). In such cases, it is presumed that the field's type is an interface
039     * implemented by the actual mixin. The default value (the empty string) directs Tapestry to use the field type as
040     * the mixin class to instantiate and attach to the component.
041     */
042    String value() default "";
043
044    /**
045     * Defines an ordering constraint for when the mixin should be applied in relation to other mixins.
046     * The string is analagous exactly to the strings used to define ordered contributions.
047     * Eg: @Mixin(order={"before:mixina","after:mixinb"}). The ids are mixin names and are case insensitive.
048     * @since 5.2.0.0
049     */
050    String[] order() default {};
051}