001// Copyright 2007, 2008, 2009, 2011 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.ioc.annotations;
016
017import java.lang.annotation.Documented;
018import java.lang.annotation.Retention;
019import java.lang.annotation.Target;
020
021import static java.lang.annotation.ElementType.FIELD;
022import static java.lang.annotation.ElementType.PARAMETER;
023import static java.lang.annotation.RetentionPolicy.RUNTIME;
024import static org.apache.tapestry5.ioc.annotations.AnnotationUseContext.*;
025
026/**
027 * Used to inject a symbol value, via a symbol name. This is used much like {@link
028 * org.apache.tapestry5.ioc.annotations.Value} annotation, except that symbols are not expanded ... the entire value is
029 * a symbol name. This allows the annotation to reference a public constant variable.
030 * <p/>
031 * <p/>
032 * The injected value may be coerced from string to an alternate type (defined by the field or parameter to which
033 * the @Symbol annotation is attached). For better control, use the {@link IntermediateType} annotation as well, which
034 * allows the string to be coerced to an alternate type before being coerced a second time to the field or parameter type.
035 */
036@Target(
037        {PARAMETER, FIELD})
038@Retention(RUNTIME)
039@Documented
040@UseWith({COMPONENT, MIXIN, PAGE, SERVICE})
041public @interface Symbol
042{
043    /**
044     * The name of the symbol to inject.
045     */
046    String value();
047}