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.util; 019 020import java.lang.annotation.Annotation; 021import java.lang.reflect.AccessibleObject; 022import java.lang.reflect.Field; 023import java.lang.reflect.InvocationTargetException; 024import java.lang.reflect.Method; 025import java.lang.reflect.Modifier; 026import java.util.Collection; 027import java.util.List; 028import java.util.Map; 029import java.util.Objects; 030 031import org.apache.logging.log4j.Logger; 032import org.apache.logging.log4j.core.LogEvent; 033import org.apache.logging.log4j.core.config.Configuration; 034import org.apache.logging.log4j.core.config.ConfigurationException; 035import org.apache.logging.log4j.core.config.Node; 036import org.apache.logging.log4j.core.config.plugins.PluginAliases; 037import org.apache.logging.log4j.core.config.plugins.PluginBuilderFactory; 038import org.apache.logging.log4j.core.config.plugins.PluginFactory; 039import org.apache.logging.log4j.core.config.plugins.validation.ConstraintValidator; 040import org.apache.logging.log4j.core.config.plugins.validation.ConstraintValidators; 041import org.apache.logging.log4j.core.config.plugins.visitors.PluginVisitor; 042import org.apache.logging.log4j.core.config.plugins.visitors.PluginVisitors; 043import org.apache.logging.log4j.core.util.Builder; 044import org.apache.logging.log4j.core.util.ReflectionUtil; 045import org.apache.logging.log4j.core.util.TypeUtil; 046import org.apache.logging.log4j.status.StatusLogger; 047import org.apache.logging.log4j.util.StringBuilders; 048 049/** 050 * Builder class to instantiate and configure a Plugin object using a PluginFactory method or PluginBuilderFactory 051 * builder class. 052 */ 053public class PluginBuilder implements Builder<Object> { 054 055 private static final Logger LOGGER = StatusLogger.getLogger(); 056 057 private final PluginType<?> pluginType; 058 private final Class<?> clazz; 059 060 private Configuration configuration; 061 private Node node; 062 private LogEvent event; 063 064 /** 065 * Constructs a PluginBuilder for a given PluginType. 066 * 067 * @param pluginType type of plugin to configure 068 */ 069 public PluginBuilder(final PluginType<?> pluginType) { 070 this.pluginType = pluginType; 071 this.clazz = pluginType.getPluginClass(); 072 } 073 074 /** 075 * Specifies the Configuration to use for constructing the plugin instance. 076 * 077 * @param configuration the configuration to use. 078 * @return {@code this} 079 */ 080 public PluginBuilder withConfiguration(final Configuration configuration) { 081 this.configuration = configuration; 082 return this; 083 } 084 085 /** 086 * Specifies the Node corresponding to the plugin object that will be created. 087 * 088 * @param node the plugin configuration node to use. 089 * @return {@code this} 090 */ 091 public PluginBuilder withConfigurationNode(final Node node) { 092 this.node = node; 093 return this; 094 } 095 096 /** 097 * Specifies the LogEvent that may be used to provide extra context for string substitutions. 098 * 099 * @param event the event to use for extra information. 100 * @return {@code this} 101 */ 102 public PluginBuilder forLogEvent(final LogEvent event) { 103 this.event = event; 104 return this; 105 } 106 107 /** 108 * Builds the plugin object. 109 * 110 * @return the plugin object or {@code null} if there was a problem creating it. 111 */ 112 @Override 113 public Object build() { 114 verify(); 115 // first try to use a builder class if one is available 116 try { 117 LOGGER.debug("Building Plugin[name={}, class={}]. Searching for builder factory method...", pluginType.getElementName(), 118 pluginType.getPluginClass().getName()); 119 final Builder<?> builder = createBuilder(this.clazz); 120 if (builder != null) { 121 injectFields(builder); 122 final Object result = builder.build(); 123 LOGGER.debug("Built Plugin[name={}] OK from builder factory method.", pluginType.getElementName()); 124 return result; 125 } 126 } catch (final Exception e) { 127 LOGGER.error("Unable to inject fields into builder class for plugin type {}, element {}.", this.clazz, 128 node.getName(), e); 129 } 130 // or fall back to factory method if no builder class is available 131 try { 132 LOGGER.debug("Still building Plugin[name={}, class={}]. Searching for factory method...", 133 pluginType.getElementName(), pluginType.getPluginClass().getName()); 134 final Method factory = findFactoryMethod(this.clazz); 135 final Object[] params = generateParameters(factory); 136 final Object plugin = factory.invoke(null, params); 137 LOGGER.debug("Built Plugin[name={}] OK from factory method.", pluginType.getElementName()); 138 return plugin; 139 } catch (final Exception e) { 140 LOGGER.error("Unable to invoke factory method in class {} for element {}.", this.clazz, this.node.getName(), 141 e); 142 return null; 143 } 144 } 145 146 private void verify() { 147 Objects.requireNonNull(this.configuration, "No Configuration object was set."); 148 Objects.requireNonNull(this.node, "No Node object was set."); 149 } 150 151 private static Builder<?> createBuilder(final Class<?> clazz) 152 throws InvocationTargetException, IllegalAccessException { 153 for (final Method method : clazz.getDeclaredMethods()) { 154 if (method.isAnnotationPresent(PluginBuilderFactory.class) && 155 Modifier.isStatic(method.getModifiers()) && 156 TypeUtil.isAssignable(Builder.class, method.getGenericReturnType())) { 157 ReflectionUtil.makeAccessible(method); 158 final Builder<?> builder = (Builder<?>) method.invoke(null); 159 LOGGER.debug("Found builder factory method [{}]: {}.", method.getName(), method); 160 return builder; 161 } 162 } 163 LOGGER.debug("No builder factory method found in class {}. Going to try finding a factory method instead.", 164 clazz.getName()); 165 return null; 166 } 167 168 private void injectFields(final Builder<?> builder) throws IllegalAccessException { 169 final Field[] fields = builder.getClass().getDeclaredFields(); 170 AccessibleObject.setAccessible(fields, true); 171 final StringBuilder log = new StringBuilder(); 172 boolean invalid = false; 173 for (final Field field : fields) { 174 log.append(log.length() == 0 ? "with params(" : ", "); 175 final Annotation[] annotations = field.getDeclaredAnnotations(); 176 final String[] aliases = extractPluginAliases(annotations); 177 for (final Annotation a : annotations) { 178 if (a instanceof PluginAliases) { 179 continue; // already processed 180 } 181 final PluginVisitor<? extends Annotation> visitor = 182 PluginVisitors.findVisitor(a.annotationType()); 183 if (visitor != null) { 184 final Object value = visitor.setAliases(aliases) 185 .setAnnotation(a) 186 .setConversionType(field.getType()) 187 .setStrSubstitutor(configuration.getStrSubstitutor()) 188 .setMember(field) 189 .visit(configuration, node, event, log); 190 // don't overwrite default values if the visitor gives us no value to inject 191 if (value != null) { 192 field.set(builder, value); 193 } 194 } 195 } 196 final Collection<ConstraintValidator<?>> validators = 197 ConstraintValidators.findValidators(annotations); 198 final Object value = field.get(builder); 199 for (final ConstraintValidator<?> validator : validators) { 200 if (!validator.isValid(value)) { 201 invalid = true; 202 } 203 } 204 } 205 if (log.length() > 0) { 206 log.append(')'); 207 } 208 LOGGER.debug("Calling build() on class {} for element {} {}", builder.getClass(), node.getName(), 209 log.toString()); 210 if (invalid) { 211 throw new ConfigurationException("Arguments given for element " + node.getName() + " are invalid"); 212 } 213 checkForRemainingAttributes(); 214 verifyNodeChildrenUsed(); 215 } 216 217 private static Method findFactoryMethod(final Class<?> clazz) { 218 for (final Method method : clazz.getDeclaredMethods()) { 219 if (method.isAnnotationPresent(PluginFactory.class) && 220 Modifier.isStatic(method.getModifiers())) { 221 LOGGER.debug("Found factory method [{}]: {}.", method.getName(), method); 222 ReflectionUtil.makeAccessible(method); 223 return method; 224 } 225 } 226 throw new IllegalStateException("No factory method found for class " + clazz.getName()); 227 } 228 229 private Object[] generateParameters(final Method factory) { 230 final StringBuilder log = new StringBuilder(); 231 final Class<?>[] types = factory.getParameterTypes(); 232 final Annotation[][] annotations = factory.getParameterAnnotations(); 233 final Object[] args = new Object[annotations.length]; 234 boolean invalid = false; 235 for (int i = 0; i < annotations.length; i++) { 236 log.append(log.length() == 0 ? "with params(" : ", "); 237 final String[] aliases = extractPluginAliases(annotations[i]); 238 for (final Annotation a : annotations[i]) { 239 if (a instanceof PluginAliases) { 240 continue; // already processed 241 } 242 final PluginVisitor<? extends Annotation> visitor = PluginVisitors.findVisitor( 243 a.annotationType()); 244 if (visitor != null) { 245 final Object value = visitor.setAliases(aliases) 246 .setAnnotation(a) 247 .setConversionType(types[i]) 248 .setStrSubstitutor(configuration.getStrSubstitutor()) 249 .setMember(factory) 250 .visit(configuration, node, event, log); 251 // don't overwrite existing values if the visitor gives us no value to inject 252 if (value != null) { 253 args[i] = value; 254 } 255 } 256 } 257 final Collection<ConstraintValidator<?>> validators = 258 ConstraintValidators.findValidators(annotations[i]); 259 final Object value = args[i]; 260 for (final ConstraintValidator<?> validator : validators) { 261 if (!validator.isValid(value)) { 262 invalid = true; 263 } 264 } 265 } 266 if (log.length() > 0) { 267 log.append(')'); 268 } 269 checkForRemainingAttributes(); 270 verifyNodeChildrenUsed(); 271 LOGGER.debug("Calling {} on class {} for element {} {}", factory.getName(), clazz.getName(), node.getName(), 272 log.toString()); 273 if (invalid) { 274 throw new ConfigurationException("Arguments given for element " + node.getName() + " are invalid"); 275 } 276 return args; 277 } 278 279 private static String[] extractPluginAliases(final Annotation... parmTypes) { 280 String[] aliases = null; 281 for (final Annotation a : parmTypes) { 282 if (a instanceof PluginAliases) { 283 aliases = ((PluginAliases) a).value(); 284 } 285 } 286 return aliases; 287 } 288 289 private void checkForRemainingAttributes() { 290 final Map<String, String> attrs = node.getAttributes(); 291 if (!attrs.isEmpty()) { 292 final StringBuilder sb = new StringBuilder(); 293 for (final String key : attrs.keySet()) { 294 if (sb.length() == 0) { 295 sb.append(node.getName()); 296 sb.append(" contains "); 297 if (attrs.size() == 1) { 298 sb.append("an invalid element or attribute "); 299 } else { 300 sb.append("invalid attributes "); 301 } 302 } else { 303 sb.append(", "); 304 } 305 StringBuilders.appendDqValue(sb, key); 306 } 307 LOGGER.error(sb.toString()); 308 } 309 } 310 311 private void verifyNodeChildrenUsed() { 312 final List<Node> children = node.getChildren(); 313 if (!(pluginType.isDeferChildren() || children.isEmpty())) { 314 for (final Node child : children) { 315 final String nodeType = node.getType().getElementName(); 316 final String start = nodeType.equals(node.getName()) ? node.getName() : nodeType + ' ' + node.getName(); 317 LOGGER.error("{} has no parameter that matches element {}", start, child.getName()); 318 } 319 } 320 } 321}