    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
    015package org.apache.tapestry5.annotations;
    016
    017import java.lang.annotation.Target;
    018import java.lang.annotation.ElementType;
    019import java.lang.annotation.Retention;
    020import java.lang.annotation.RetentionPolicy;
    021
    022import static org.apache.tapestry5.ioc.annotations.AnnotationUseContext.MIXIN;
    023
    024import org.apache.tapestry5.internal.transform.BindParameterWorker;
    025import 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)
    043public @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}