001    // Copyright 2007 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.services;
016    
017    import java.lang.annotation.Documented;
018    import static java.lang.annotation.ElementType.FIELD;
019    import static java.lang.annotation.ElementType.PARAMETER;
020    import java.lang.annotation.Retention;
021    import static java.lang.annotation.RetentionPolicy.RUNTIME;
022    import java.lang.annotation.Target;
023    
024    /**
025     * Marker annotation used to identify a service from the component layer that conflicts, in terms of service interface,
026     * with a service from elsewhere. In particular, this is used to disambiguate {@link
027     * org.apache.tapestry5.ioc.services.ClassFactory} which has one implementation (marked with {@link
028     * org.apache.tapestry5.ioc.services.Builtin} and another with this annotation.
029     */
030    @Target(
031            { PARAMETER, FIELD })
032    @Retention(RUNTIME)
033    @Documented
034    public @interface ComponentLayer
035    {
036    
037    }