001    // Copyright 2006, 2007 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    
015    package org.apache.tapestry.annotations;
016    
017    import java.lang.annotation.Documented;
018    import static java.lang.annotation.ElementType.FIELD;
019    import java.lang.annotation.Retention;
020    import static java.lang.annotation.RetentionPolicy.RUNTIME;
021    import java.lang.annotation.Target;
022    
023    /**
024     * Defines an <em>implementation</em> mixin for a component.
025     */
026    @Target(FIELD)
027    @Documented
028    @Retention(RUNTIME)
029    public @interface Mixin
030    {
031    
032        /**
033         * Defines the type of mixin, using a logical mixin name. This value takes precedence over the type of field (to
034         * which the annotation is attached). In such cases, it is presumed that the field's type is an interface
035         * implemented by the actual mixin. The default value (the empty string) directs Tapestry to use the field type as
036         * the mixin class to instantiate and attach to the component.
037         */
038        String value() default "";
039    }