001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018package org.apache.logging.log4j.core.config.plugins.processor;
019
020import org.apache.logging.log4j.core.util.Closer;
021
022import java.io.BufferedInputStream;
023import java.io.BufferedOutputStream;
024import java.io.DataInputStream;
025import java.io.DataOutputStream;
026import java.io.IOException;
027import java.io.OutputStream;
028import java.net.URL;
029import java.util.Enumeration;
030import java.util.LinkedHashMap;
031import java.util.Map;
032
033/**
034 *
035 */
036public class PluginCache {
037    private final Map<String, Map<String, PluginEntry>> categories =
038        new LinkedHashMap<String, Map<String, PluginEntry>>();
039
040    /**
041     * Returns all categories of plugins in this cache.
042     *
043     * @return all categories of plugins in this cache.
044     * @since 2.1
045     */
046    public Map<String, Map<String, PluginEntry>> getAllCategories() {
047        return categories;
048    }
049
050    /**
051     * Gets or creates a category of plugins.
052     *
053     * @param category name of category to look up.
054     * @return plugin mapping of names to plugin entries.
055     */
056    public Map<String, PluginEntry> getCategory(final String category) {
057        final String key = category.toLowerCase();
058        if (!categories.containsKey(key)) {
059            categories.put(key, new LinkedHashMap<String, PluginEntry>());
060        }
061        return categories.get(key);
062    }
063
064    /**
065     * Stores the plugin cache to a given OutputStream.
066     *
067     * @param os destination to save cache to.
068     * @throws IOException
069     */
070    // NOTE: if this file format is to be changed, the filename should change and this format should still be readable
071    public void writeCache(final OutputStream os) throws IOException {
072        final DataOutputStream out = new DataOutputStream(new BufferedOutputStream(os));
073        try {
074            // See PluginManager.readFromCacheFiles for the corresponding decoder. Format may not be changed
075            // without breaking existing Log4j2Plugins.dat files.
076            out.writeInt(categories.size());
077            for (final Map.Entry<String, Map<String, PluginEntry>> category : categories.entrySet()) {
078                out.writeUTF(category.getKey());
079                final Map<String, PluginEntry> m = category.getValue();
080                out.writeInt(m.size());
081                for (final Map.Entry<String, PluginEntry> entry : m.entrySet()) {
082                    final PluginEntry plugin = entry.getValue();
083                    out.writeUTF(plugin.getKey());
084                    out.writeUTF(plugin.getClassName());
085                    out.writeUTF(plugin.getName());
086                    out.writeBoolean(plugin.isPrintable());
087                    out.writeBoolean(plugin.isDefer());
088                }
089            }
090        } finally {
091            Closer.closeSilently(out);
092        }
093    }
094
095    /**
096     * Loads and merges all the Log4j plugin cache files specified. Usually, this is obtained via a ClassLoader.
097     *
098     * @param resources URLs to all the desired plugin cache files to load.
099     * @throws IOException
100     */
101    public void loadCacheFiles(final Enumeration<URL> resources) throws IOException {
102        categories.clear();
103        while (resources.hasMoreElements()) {
104            final URL url = resources.nextElement();
105            final DataInputStream in = new DataInputStream(new BufferedInputStream(url.openStream()));
106            try {
107                final int count = in.readInt();
108                for (int i = 0; i < count; i++) {
109                    final String category = in.readUTF();
110                    final Map<String, PluginEntry> m = getCategory(category);
111                    final int entries = in.readInt();
112                    for (int j = 0; j < entries; j++) {
113                        final PluginEntry entry = new PluginEntry();
114                        entry.setKey(in.readUTF());
115                        entry.setClassName(in.readUTF());
116                        entry.setName(in.readUTF());
117                        entry.setPrintable(in.readBoolean());
118                        entry.setDefer(in.readBoolean());
119                        entry.setCategory(category);
120                        if (!m.containsKey(entry.getKey())) {
121                            m.put(entry.getKey(), entry);
122                        }
123                    }
124                }
125            } finally {
126                Closer.closeSilently(in);
127            }
128        }
129    }
130
131    /**
132     * Gets the number of plugin categories registered.
133     *
134     * @return number of plugin categories in cache.
135     */
136    public int size() {
137        return categories.size();
138    }
139}