001// Copyright 2005 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.tapestry.annotations; 016 017import java.lang.annotation.Documented; 018import java.lang.annotation.ElementType; 019import java.lang.annotation.Retention; 020import java.lang.annotation.RetentionPolicy; 021import java.lang.annotation.Target; 022 023/** 024 * Used to define a parameter for the component. 025 * 026 * @author Howard Lewis Ship 027 * @since 4.0 028 */ 029 030@Target( 031{ ElementType.METHOD }) 032@Retention(RetentionPolicy.RUNTIME) 033@Documented 034public @interface Parameter { 035 036 /** 037 * If true, then the parameter is required, and must be bound (there is no guarantee that a 038 * non-null value will be bound however, so the component may have to perform additonal checks). 039 * The default value, false, means the parameter is optional. 040 */ 041 042 boolean required() default false; 043 044 /** 045 * The default value for the binding, as a binding reference. 046 */ 047 048 String defaultValue() default ""; 049 050 /** 051 * If true (the default), then the binding will cache its value while the component is 052 * renderering. In some cases, it is desirable to force the binding to be re-evaluated every 053 * time the parameter property is accessed, in which case cache should be set to false. 054 */ 055 056 boolean cache() default true; 057 058 /** 059 * An optional list of alternate names for the parameter. The parameter may be bound using its 060 * true name or any alias (but not both!), but use of aliases will generate deprecation 061 * warnings. 062 */ 063 064 String aliases() default ""; 065 066 /** 067 * The name of the parameter. If not specified, it will match the property name. Note that this 068 * is backwards from the logic in the XML, where the parameter name is specified and the property name 069 * matches. 070 * 071 */ 072 073 String name() default ""; 074}