001 // Copyright 2006, 2008, 2009, 2010, 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;
016
017 /**
018 * Object passed into a service contributor method that allows the method provide contributed values to the service's
019 * configuration.
020 * <p/>
021 * A service can <em>collect</em> contributions in three different ways:
022 * <ul>
023 * <li>As an un-ordered collection of values</li>
024 * <li>As an ordered list of values (where each value has a unique id, pre-requisites and post-requisites)</li>
025 * <li>As a map of keys and values
026 * </ul>
027 * <p/>
028 * The service defines the <em>type</em> of contribution, in terms of a base class or service interface. Contributions
029 * must be compatible with the type, or be {@linkplain org.apache.tapestry5.ioc.services.TypeCoercer coercable} to the type.
030 *
031 * @see org.apache.tapestry5.ioc.annotations.Contribute
032 * @see org.apache.tapestry5.ioc.annotations.UsesConfiguration
033 */
034 public interface OrderedConfiguration<T>
035 {
036 /**
037 * Adds an ordered object to a service's contribution. Each object has an id (which must be unique). Optionally,
038 * pre-requisites (a list of ids that must precede this object) and post-requisites (ids that must follow) can be
039 * provided.
040 * <p/>
041 * <p>If no constraints are supplied, then an implicit constraint is supplied: after the previously
042 * contributed id <em>within the same contribution method</em>.
043 *
044 * @param id a unique id for the object; the id will be fully qualified with the contributing module's id
045 * @param constraints used to order the object relative to other contributed objects
046 * @param object to add to the service's configuration
047 */
048 void add(String id, T object, String... constraints);
049
050 /**
051 * Overrides a normally contributed object. Each override must match a single normally contributed object.
052 *
053 * @param id identifies object to override
054 * @param object overriding object (may be null)
055 * @param constraints constraints for the overridden object, replacing constraints for the original object (even if
056 * omitted, in which case the override object will have no ordering constraints)
057 * @since 5.1.0.0
058 */
059 void override(String id, T object, String... constraints);
060
061 /**
062 * Adds an ordered object by instantiating (with dependencies) the indicated class. When the configuration type is
063 * an interface and the class to be contributed is a local file,
064 * then a reloadable proxy for the class will be created and contributed.
065 *
066 * @param id of contribution (used for ordering)
067 * @param clazz class to instantiate
068 * @param constraints used to order the object relative to other contributed objects
069 * @since 5.1.0.0
070 */
071 void addInstance(String id, Class<? extends T> clazz, String... constraints);
072
073 /**
074 * Instantiates an object and adds it as an override. When the configuration type is an interface and the class to
075 * be contributed is a local file, then a reloadable proxy for the class will be created and contributed.
076 *
077 * @param id of object to override
078 * @param clazz to instantiate
079 * @param constraints constraints for the overridden object, replacing constraints for the original object (even if
080 * omitted, in which case the override object will have no ordering constraints)
081 * @since 5.1.0.0
082 */
083 void overrideInstance(String id, Class<? extends T> clazz, String... constraints);
084 }