001/*
002    Licensed to the Apache Software Foundation (ASF) under one
003    or more contributor license agreements.  See the NOTICE file
004    distributed with this work for additional information
005    regarding copyright ownership.  The ASF licenses this file
006    to you under the Apache License, Version 2.0 (the
007    "License"); you may not use this file except in compliance
008    with the License.  You may obtain a copy of the License at
009
010       http://www.apache.org/licenses/LICENSE-2.0
011
012    Unless required by applicable law or agreed to in writing,
013    software distributed under the License is distributed on an
014    "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015    KIND, either express or implied.  See the License for the
016    specific language governing permissions and limitations
017    under the License.
018 */
019package org.apache.wiki.cache;
020
021
022import org.apache.wiki.util.CheckedSupplier;
023
024import java.io.Serializable;
025import java.util.List;
026
027/**
028 * Cache manager abstraction.
029 */
030public interface CachingManager {
031
032    /**
033     * The property value for setting the cache on/off.  Value is {@value}.
034     * This key is deprecated, use instead {@link #PROP_CACHE_ENABLE}.
035     */
036    @Deprecated
037    String PROP_USECACHE_DEPRECATED = "jspwiki.usePageCache";
038
039    /** The property value for setting the cache on/off.  Value is {@value}. */
040    String PROP_CACHE_ENABLE = "jspwiki.cache.enable";
041
042    /** The property value with the location of the cache configuration file.  Value is {@value}. */
043    String PROP_CACHE_CONF_FILE = "jspwiki.cache.config-file";
044
045    /** Name of the attachment cache. */
046    String CACHE_ATTACHMENTS = "jspwiki.attachmentsCache";
047
048    /** Name of the collection attachment cache. */
049    String CACHE_ATTACHMENTS_COLLECTION = "jspwiki.attachmentCollectionsCache";
050
051    /** Name of the dynamic attachment cache. */
052    String CACHE_ATTACHMENTS_DYNAMIC = "jspwiki.dynamicAttachmentCache";
053
054    /** Name of the page cache. */
055    String CACHE_PAGES = "jspwiki.pageCache";
056
057    /** Name of the page text cache. */
058    String CACHE_PAGES_TEXT = "jspwiki.pageTextCache";
059
060    /** Name of the page history cache. */
061    String CACHE_PAGES_HISTORY = "jspwiki.pageHistoryCache";
062
063    /** Name of the rendering cache. */
064    String CACHE_DOCUMENTS = "jspwiki.renderingCache";
065
066    /**
067     * Shuts down the underlying cache manager
068     */
069    void shutdown();
070
071    /**
072     * Checks if the requested cache is enabled or not.
073     *
074     * @param cacheName The cache to be queried.
075     * @return {@code true} if the cache is enabled, {@code false} otherwise.
076     */
077    boolean enabled( String cacheName );
078
079    /**
080     * Retrieves cache usage information.
081     *
082     * @param cacheName The cache to be queried.
083     * @return cache usage information, or {@code null} if the requested cache is not enabled.
084     */
085    CacheInfo info( String cacheName );
086
087    /**
088     * Returns the list of keys from elements present in a cache.
089     *
090     * @param cacheName The cache to be queried.
091     * @return list of keys from elements present in a cache.
092     */
093    < T extends Serializable > List< T > keys( String cacheName );
094
095    /**
096     * Returns an item from a cache. If it is not found on the cache, try to retrieve from the provided supplier. If
097     * found there, put the value in the cache, and return it. Otherwise, return {@code null}.
098     *
099     * @param cacheName The cache in which the item lives.
100     * @param key item's identifier.
101     * @param supplier if the element is not cached, try to retrieve from the cached system.
102     * @throws E the supplier may throw a checked exception, which is propagated upwards.
103     * @return The requested item or {@code null} if either the cache is not enabled or the item is not present on the cache / cached service.
104     */
105    < T, E extends Exception > T get( String cacheName, Serializable key, CheckedSupplier< T, E > supplier ) throws E;
106
107    /**
108     * Puts an item on a cache.
109     *
110     * @param cacheName The cache in which the item will live.
111     * @param key item's identifier.
112     * @param val item to insert in the cache.
113     */
114    void put( String cacheName, Serializable key, Object val );
115
116    /**
117     * Removes an item from a cache.
118     *
119     * @param cacheName The cache in which the item to be removed lives.
120     * @param key item's identifier.
121     */
122    void remove( String cacheName, Serializable key );
123
124}