    001    // Copyright 2009 , 2010 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.tapestry5.annotations;
    016
    017    import java.lang.annotation.Target;
    018    import java.lang.annotation.ElementType;
    019    import java.lang.annotation.Retention;
    020    import java.lang.annotation.RetentionPolicy;
    021
    022    import static org.apache.tapestry5.ioc.annotations.AnnotationUseContext.MIXIN;
    023
    024    import org.apache.tapestry5.internal.transform.BindParameterWorker;
    025    import org.apache.tapestry5.ioc.annotations.UseWith;
    026
    027    /**
    028     * Designates a field in a mixin which is bound to the parameter of the containing
    029     * component corresponding to the value of the annotation. If no value is specified,
    030     * the bound parameter name is assumed to match the field name of the mixin.
    031     * For example, a mixin intended to work with form fields would define a field named
    032     * "value", marked by this annotation. The user-variable bound to the component's value
    033     * parameter would ultimately be bound in a chain:
    034     * uservariable <=> mixin.value <=> component.value.
    035     * Changes to any one value in the chain will be propagated accordingly.
    036     *
    037     * @since 5.2.0
    038     * @see BindParameterWorker
    039     */
    040    @Target(ElementType.FIELD)
    041    @Retention(RetentionPolicy.RUNTIME)
    042    @UseWith(MIXIN)
    043    public @interface BindParameter
    044    {
    045
    046        /**
    047         * @return the name of the mixin bound-parameter, exactly as for the Parameter annotation.
    048         */
    049        String name() default "";
    050
    051        /**
    052         * @return the name(s) of the parent parameter to bind. Defaults to the name of the mixin field.
    053         *         If more than one
    054         *         name is specified, the first name matching a declared parameter of the core component
    055         *         will be used.
    056         */
    057        String[] value() default
    058        { "" };
    059    }