    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
    015    package org.apache.tapestry5.ioc.annotations;
    016
    017    import java.lang.annotation.Documented;
    018    import java.lang.annotation.Retention;
    019    import java.lang.annotation.Target;
    020
    021    import static java.lang.annotation.ElementType.FIELD;
    022    import static java.lang.annotation.ElementType.PARAMETER;
    023    import static java.lang.annotation.RetentionPolicy.RUNTIME;
    024    import 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})
    041    public @interface Symbol
    042    {
    043        /**
    044         * The name of the symbol to inject.
    045         */
    046        String value();
    047    }