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.services;
014
015import java.util.List;
016import java.util.Map;
017import java.util.function.Function;
018
019import org.apache.tapestry5.ioc.annotations.IncompatibleChange;
020
021/**
022 * An object which manages a list of {@link org.apache.tapestry5.commons.services.InvalidationListener}s. There are multiple
023 * event hub services implementing this interface, each with a specific marker annotation; each can register listeners
024 * and fire events; these are based on the type of resource that has been invalidated. Tapestry has built-in support
025 * for:
026 * <dl>
027 * <dt>message catalog resources
028 * <dd><a href="https://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/ComponentMessages.html">ComponentMessages</a> marker annotation
029 * <dt>component templates
030 * <dd><a href="https://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/ComponentTemplates.html">ComponentTemplates</a> marker annotation
031 * <dt>component classes
032 * <dd><a href="https://tapestry.apache.org/current/apidocs/org/apache/tapestry5/services/ComponentClasses.html">ComponentClasses</a> marker annotation
033 * </dl>
034 *
035 * Starting in Tapestry 5.3, these services are disabled in production (it does nothing).
036 *
037 * @since 5.1.0.0
038 */
039public interface InvalidationEventHub
040{
041    /**
042     * Adds a listener, who needs to know when an underlying resource of a given category has changed (so that the
043     * receiver may discard any cached data that may have been invalidated). Does nothing in production mode.
044     *
045     * @deprecated in 5.4, use {@link #addInvalidationCallback(Runnable)} instead}
046     */
047    void addInvalidationListener(InvalidationListener listener);
048
049    /**
050     * Adds a callback that is invoked when an underlying tracked resource has changed. Does nothing in production mode.
051     *
052     * @since  5.4
053     */
054    void addInvalidationCallback(Runnable callback);
055
056    /**
057     * Adds a callback that clears the map.
058     *
059     * @since 5.4
060     */
061    void clearOnInvalidation(Map<?,?> map);
062
063    /**
064     * Adds a callback, as a function that receives a list of strings and also returns a list of strings,
065     * that is invoked when one or more listed underlying tracked resource have changed. 
066     * An empty list should be considered as all resources being changed and any caches needing to be cleared.
067     * The return value of the function should be a non-null, but possibly empty, list of other resources that also
068     * need to be invalidated in a recursive fashion.
069     * This method does nothing in production mode.
070     * @since 5.8.3
071     */
072    @IncompatibleChange(release = "5.8.3", details = "Added method")
073    void addInvalidationCallback(Function<List<String>, List<String>> function);
074    
075   /** 
076    * Notify resource-specific invalidations to listeners.
077    * @since 5.8.3
078    */
079   @IncompatibleChange(release = "5.8.3", details = "Added method")
080   void fireInvalidationEvent(List<String> resources);
081
082}