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 java.io.IOException; 021import java.io.OutputStream; 022import java.util.ArrayList; 023import java.util.Collection; 024import java.util.Collections; 025import java.util.Locale; 026import java.util.Map; 027import java.util.Objects; 028import java.util.Set; 029import javax.annotation.processing.AbstractProcessor; 030import javax.annotation.processing.RoundEnvironment; 031import javax.annotation.processing.SupportedAnnotationTypes; 032import javax.lang.model.SourceVersion; 033import javax.lang.model.element.Element; 034import javax.lang.model.element.ElementVisitor; 035import javax.lang.model.element.TypeElement; 036import javax.lang.model.util.Elements; 037import javax.lang.model.util.SimpleElementVisitor7; 038import javax.tools.Diagnostic.Kind; 039import javax.tools.FileObject; 040import javax.tools.StandardLocation; 041 042import org.apache.logging.log4j.core.config.plugins.Plugin; 043import org.apache.logging.log4j.core.config.plugins.PluginAliases; 044import org.apache.logging.log4j.util.Strings; 045 046/** 047 * Annotation processor for pre-scanning Log4j 2 plugins. 048 */ 049@SupportedAnnotationTypes("org.apache.logging.log4j.core.config.plugins.*") 050public class PluginProcessor extends AbstractProcessor { 051 052 // TODO: this could be made more abstract to allow for compile-time and run-time plugin processing 053 054 /** 055 * The location of the plugin cache data file. This file is written to by this processor, and read from by 056 * {@link org.apache.logging.log4j.core.config.plugins.util.PluginManager}. 057 */ 058 public static final String PLUGIN_CACHE_FILE = 059 "META-INF/org/apache/logging/log4j/core/config/plugins/Log4j2Plugins.dat"; 060 061 private final PluginCache pluginCache = new PluginCache(); 062 063 @Override 064 public SourceVersion getSupportedSourceVersion() { 065 return SourceVersion.latest(); 066 } 067 068 @Override 069 public boolean process(final Set<? extends TypeElement> annotations, final RoundEnvironment roundEnv) { 070 System.out.println("Processing annotations"); 071 try { 072 final Set<? extends Element> elements = roundEnv.getElementsAnnotatedWith(Plugin.class); 073 if (elements.isEmpty()) { 074 System.out.println("No elements to process"); 075 return false; 076 } 077 collectPlugins(elements); 078 writeCacheFile(elements.toArray(new Element[elements.size()])); 079 System.out.println("Annotations processed"); 080 return true; 081 } catch (final IOException e) { 082 e.printStackTrace(); 083 error(e.getMessage()); 084 return false; 085 } catch (final Exception ex) { 086 ex.printStackTrace(); 087 error(ex.getMessage()); 088 return false; 089 } 090 } 091 092 private void error(final CharSequence message) { 093 processingEnv.getMessager().printMessage(Kind.ERROR, message); 094 } 095 096 private void collectPlugins(final Iterable<? extends Element> elements) { 097 final Elements elementUtils = processingEnv.getElementUtils(); 098 final ElementVisitor<PluginEntry, Plugin> pluginVisitor = new PluginElementVisitor(elementUtils); 099 final ElementVisitor<Collection<PluginEntry>, Plugin> pluginAliasesVisitor = new PluginAliasesElementVisitor( 100 elementUtils); 101 for (final Element element : elements) { 102 final Plugin plugin = element.getAnnotation(Plugin.class); 103 if (plugin == null) { 104 continue; 105 } 106 final PluginEntry entry = element.accept(pluginVisitor, plugin); 107 final Map<String, PluginEntry> category = pluginCache.getCategory(entry.getCategory()); 108 category.put(entry.getKey(), entry); 109 final Collection<PluginEntry> entries = element.accept(pluginAliasesVisitor, plugin); 110 for (final PluginEntry pluginEntry : entries) { 111 category.put(pluginEntry.getKey(), pluginEntry); 112 } 113 } 114 } 115 116 private void writeCacheFile(final Element... elements) throws IOException { 117 final FileObject fileObject = processingEnv.getFiler().createResource(StandardLocation.CLASS_OUTPUT, Strings.EMPTY, 118 PLUGIN_CACHE_FILE, elements); 119 try (final OutputStream out = fileObject.openOutputStream()) { 120 pluginCache.writeCache(out); 121 } 122 } 123 124 /** 125 * ElementVisitor to scan the Plugin annotation. 126 */ 127 private static class PluginElementVisitor extends SimpleElementVisitor7<PluginEntry, Plugin> { 128 129 private final Elements elements; 130 131 private PluginElementVisitor(final Elements elements) { 132 this.elements = elements; 133 } 134 135 @Override 136 public PluginEntry visitType(final TypeElement e, final Plugin plugin) { 137 Objects.requireNonNull(plugin, "Plugin annotation is null."); 138 final PluginEntry entry = new PluginEntry(); 139 entry.setKey(plugin.name().toLowerCase(Locale.US)); 140 entry.setClassName(elements.getBinaryName(e).toString()); 141 entry.setName(Plugin.EMPTY.equals(plugin.elementType()) ? plugin.name() : plugin.elementType()); 142 entry.setPrintable(plugin.printObject()); 143 entry.setDefer(plugin.deferChildren()); 144 entry.setCategory(plugin.category()); 145 return entry; 146 } 147 } 148 149 /** 150 * ElementVisitor to scan the PluginAliases annotation. 151 */ 152 private static class PluginAliasesElementVisitor extends SimpleElementVisitor7<Collection<PluginEntry>, Plugin> { 153 154 private final Elements elements; 155 156 private PluginAliasesElementVisitor(final Elements elements) { 157 super(Collections.<PluginEntry> emptyList()); 158 this.elements = elements; 159 } 160 161 @Override 162 public Collection<PluginEntry> visitType(final TypeElement e, final Plugin plugin) { 163 final PluginAliases aliases = e.getAnnotation(PluginAliases.class); 164 if (aliases == null) { 165 return DEFAULT_VALUE; 166 } 167 final Collection<PluginEntry> entries = new ArrayList<>(aliases.value().length); 168 for (final String alias : aliases.value()) { 169 final PluginEntry entry = new PluginEntry(); 170 entry.setKey(alias.toLowerCase(Locale.US)); 171 entry.setClassName(elements.getBinaryName(e).toString()); 172 entry.setName(Plugin.EMPTY.equals(plugin.elementType()) ? alias : plugin.elementType()); 173 entry.setPrintable(plugin.printObject()); 174 entry.setDefer(plugin.deferChildren()); 175 entry.setCategory(plugin.category()); 176 entries.add(entry); 177 } 178 return entries; 179 } 180 } 181}