001// Licensed under the Apache License, Version 2.0 (the "License");
002// you may not use this file except in compliance with the License.
003// You may obtain a copy of the License at
004//
005//     http://www.apache.org/licenses/LICENSE-2.0
006//
007// Unless required by applicable law or agreed to in writing, software
008// distributed under the License is distributed on an "AS IS" BASIS,
009// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
010// See the License for the specific language governing permissions and
011// limitations under the License.
012
013package org.apache.tapestry5.ioc.annotations;
014
015import java.lang.annotation.Documented;
016import java.lang.annotation.Retention;
017import java.lang.annotation.Target;
018
019import static java.lang.annotation.ElementType.FIELD;
020import static java.lang.annotation.ElementType.PARAMETER;
021import static java.lang.annotation.RetentionPolicy.RUNTIME;
022import static org.apache.tapestry5.ioc.annotations.AnnotationUseContext.*;
023
024/**
025 * Used to inject a symbol value, via a symbol name. This is used much like {@link
026 * org.apache.tapestry5.ioc.annotations.Value} annotation, except that symbols are not expanded ... the entire value is
027 * a symbol name. This allows the annotation to reference a public constant variable.
028 *
029 *
030 * The injected value may be coerced from string to an alternate type (defined by the field or parameter to which
031 * the @Symbol annotation is attached). For better control, use the {@link IntermediateType} annotation as well, which
032 * allows the string to be coerced to an alternate type before being coerced a second time to the field or parameter type.
033 */
034@Target(
035        {PARAMETER, FIELD})
036@Retention(RUNTIME)
037@Documented
038@UseWith({COMPONENT, MIXIN, PAGE, SERVICE})
039public @interface Symbol
040{
041    /**
042     * The name of the symbol to inject.
043     */
044    String value();
045}