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    package org.apache.logging.log4j.core.appender.db.jpa;
018    
019    import java.lang.reflect.Constructor;
020    
021    import org.apache.logging.log4j.core.Filter;
022    import org.apache.logging.log4j.core.LogEvent;
023    import org.apache.logging.log4j.core.appender.AbstractAppender;
024    import org.apache.logging.log4j.core.appender.db.AbstractDatabaseAppender;
025    import org.apache.logging.log4j.core.config.plugins.Plugin;
026    import org.apache.logging.log4j.core.config.plugins.PluginAttribute;
027    import org.apache.logging.log4j.core.config.plugins.PluginElement;
028    import org.apache.logging.log4j.core.config.plugins.PluginFactory;
029    import org.apache.logging.log4j.core.util.Booleans;
030    import org.apache.logging.log4j.core.util.Loader;
031    import org.apache.logging.log4j.util.Strings;
032    
033    /**
034     * This Appender writes logging events to a relational database using the Java Persistence API. It requires a
035     * pre-configured JPA persistence unit and a concrete implementation of the abstract
036     * {@link AbstractLogEventWrapperEntity} class decorated with JPA annotations.
037     *
038     * @see AbstractLogEventWrapperEntity
039     */
040    @Plugin(name = "JPA", category = "Core", elementType = "appender", printObject = true)
041    public final class JpaAppender extends AbstractDatabaseAppender<JpaDatabaseManager> {
042        private static final long serialVersionUID = 1L;
043    
044        private final String description;
045    
046        private JpaAppender(final String name, final Filter filter, final boolean ignoreExceptions,
047                final JpaDatabaseManager manager) {
048            super(name, filter, ignoreExceptions, manager);
049            this.description = this.getName() + "{ manager=" + this.getManager() + " }";
050        }
051    
052        @Override
053        public String toString() {
054            return this.description;
055        }
056    
057        /**
058         * Factory method for creating a JPA appender within the plugin manager.
059         *
060         * @param name The name of the appender.
061         * @param ignore If {@code "true"} (default) exceptions encountered when appending events are logged; otherwise
062         *               they are propagated to the caller.
063         * @param filter The filter, if any, to use.
064         * @param bufferSize If an integer greater than 0, this causes the appender to buffer log events and flush whenever
065         *                   the buffer reaches this size.
066         * @param entityClassName The fully qualified name of the concrete {@link AbstractLogEventWrapperEntity}
067         *                        implementation that has JPA annotations mapping it to a database table.
068         * @param persistenceUnitName The name of the JPA persistence unit that should be used for persisting log events.
069         * @return a new JPA appender.
070         */
071        @PluginFactory
072        public static JpaAppender createAppender(
073                @PluginAttribute("name") final String name,
074                @PluginAttribute("ignoreExceptions") final String ignore,
075                @PluginElement("Filter") final Filter filter,
076                @PluginAttribute("bufferSize") final String bufferSize,
077                @PluginAttribute("entityClassName") final String entityClassName,
078                @PluginAttribute("persistenceUnitName") final String persistenceUnitName) {
079            if (Strings.isEmpty(entityClassName) || Strings.isEmpty(persistenceUnitName)) {
080                LOGGER.error("Attributes entityClassName and persistenceUnitName are required for JPA Appender.");
081                return null;
082            }
083    
084            final int bufferSizeInt = AbstractAppender.parseInt(bufferSize, 0);
085            final boolean ignoreExceptions = Booleans.parseBoolean(ignore, true);
086    
087            try {
088                @SuppressWarnings("unchecked")
089                final Class<? extends AbstractLogEventWrapperEntity> entityClass =
090                        (Class<? extends AbstractLogEventWrapperEntity>) Loader.loadClass(entityClassName);
091    
092                if (!AbstractLogEventWrapperEntity.class.isAssignableFrom(entityClass)) {
093                    LOGGER.error("Entity class [{}] does not extend AbstractLogEventWrapperEntity.", entityClassName);
094                    return null;
095                }
096    
097                try {
098                    entityClass.getConstructor();
099                } catch (final NoSuchMethodException e) {
100                    LOGGER.error("Entity class [{}] does not have a no-arg constructor. The JPA provider will reject it.",
101                            entityClassName);
102                    return null;
103                }
104    
105                final Constructor<? extends AbstractLogEventWrapperEntity> entityConstructor =
106                        entityClass.getConstructor(LogEvent.class);
107    
108                final String managerName = "jpaManager{ description=" + name + ", bufferSize=" + bufferSizeInt
109                        + ", persistenceUnitName=" + persistenceUnitName + ", entityClass=" + entityClass.getName() + '}';
110    
111                final JpaDatabaseManager manager = JpaDatabaseManager.getJPADatabaseManager(
112                        managerName, bufferSizeInt, entityClass, entityConstructor, persistenceUnitName
113                );
114                if (manager == null) {
115                    return null;
116                }
117    
118                return new JpaAppender(name, filter, ignoreExceptions, manager);
119            } catch (final ClassNotFoundException e) {
120                LOGGER.error("Could not load entity class [{}].", entityClassName, e);
121                return null;
122            } catch (final NoSuchMethodException e) {
123                LOGGER.error("Entity class [{}] does not have a constructor with a single argument of type LogEvent.",
124                        entityClassName);
125                return null;
126            }
127        }
128    }