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.commons;
014
015/**
016 * Object passed into a service contributor method that allows the method provide contributed values to the service's
017 * configuration.
018 *
019 * A service can <em>collect</em> contributions in three different ways:
020 * <ul>
021 * <li>As an un-ordered collection of values</li>
022 * <li>As an ordered list of values (where each value has a unique id, pre-requisites and post-requisites)</li>
023 * <li>As a map of keys and values
024 * </ul>
025 *
026 * The service defines the <em>type</em> of contribution, in terms of a base class or service interface. Contributions
027 * must be compatible with the type.
028 */
029public interface MappedConfiguration<K, V>
030{
031
032    /**
033     * Adds a keyed object to the service's contribution.
034     * 
035     * @param key
036     *            unique id for the value
037     * @param value
038     *            to contribute
039     * @throws IllegalArgumentException
040     *             if key is not unique
041     */
042    void add(K key, V value);
043
044    /**
045     * Overrides an existing contribution by its key.
046     * 
047     * @param key
048     *            unique id of value to override
049     * @param value
050     *            new value, or null to remove the key entirely
051     * @since 5.1.0.0
052     */
053    void override(K key, V value);
054
055    /**
056     * Adds a keyed object as an instantiated instance (with dependencies injected) of a class. When the value
057     * type is an interface and the class to be contributed is a local file,
058     * then a reloadable proxy for the value class will be created and contributed.
059     * 
060     * @param key
061     *            unique id for the value
062     * @param clazz
063     *            class to instantiate and contribute
064     * @since 5.1.0.0
065     */
066    void addInstance(K key, Class<? extends V> clazz);
067
068    /**
069     * Overrides an existing contribution with a new instance. When the value
070     * type is an interface and the class to be contributed is a local file,
071     * then a reloadable proxy for the value class will be created and contributed.
072     * 
073     * @param key
074     *            unique id of value to override
075     * @param clazz
076     *            class to instantiate as override
077     */
078    void overrideInstance(K key, Class<? extends V> clazz);
079}