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.db.AbstractDatabaseAppender;
024    import org.apache.logging.log4j.core.config.plugins.Plugin;
025    import org.apache.logging.log4j.core.config.plugins.PluginAttr;
026    import org.apache.logging.log4j.core.config.plugins.PluginElement;
027    import org.apache.logging.log4j.core.config.plugins.PluginFactory;
028    
029    /**
030     * This Appender writes logging events to a relational database using the Java Persistence API. It requires a
031     * pre-configured JPA persistence unit and a concrete implementation of the abstract
032     * {@link AbstractLogEventWrapperEntity} class decorated with JPA annotations.
033     * 
034     * @see AbstractLogEventWrapperEntity
035     */
036    @Plugin(name = "Jpa", category = "Core", elementType = "appender", printObject = true)
037    public final class JPAAppender extends AbstractDatabaseAppender<JPADatabaseManager> {
038        private final String description;
039    
040        private JPAAppender(final String name, final Filter filter, final boolean handleException,
041                final JPADatabaseManager manager) {
042            super(name, filter, handleException, manager);
043            this.description = this.getName() + "{ manager=" + this.getManager() + " }";
044        }
045    
046        @Override
047        public String toString() {
048            return this.description;
049        }
050    
051        /**
052         * Factory method for creating a JPA appender within the plugin manager.
053         *
054         * @param name The name of the appender.
055         * @param suppressExceptions {@code "true"} (default) if logging exceptions should be hidden from the application,
056         *                           {@code "false"} otherwise.
057         * @param filter The filter, if any, to use.
058         * @param bufferSize If an integer greater than 0, this causes the appender to buffer log events and flush whenever
059         *                   the buffer reaches this size.
060         * @param entityClassName The fully qualified name of the concrete {@link AbstractLogEventWrapperEntity}
061         *                        implementation that has JPA annotations mapping it to a database table.
062         * @param persistenceUnitName The name of the JPA persistence unit that should be used for persisting log events.
063         * @return a new JPA appender.
064         */
065        @PluginFactory
066        public static JPAAppender createAppender(@PluginAttr("name") final String name,
067                                                 @PluginAttr("suppressExceptions") final String suppressExceptions,
068                                                 @PluginElement("filter") final Filter filter,
069                                                 @PluginAttr("bufferSize") final String bufferSize,
070                                                 @PluginAttr("entityClassName") final String entityClassName,
071                                                 @PluginAttr("persistenceUnitName") final String persistenceUnitName) {
072            if (entityClassName == null || entityClassName.length() == 0 ||
073                    persistenceUnitName == null || persistenceUnitName.length() == 0) {
074                LOGGER.error("Attributes entityClassName and persistenceUnitName are required for JPA Appender.");
075                return null;
076            }
077    
078            int bufferSizeInt;
079            try {
080                bufferSizeInt = bufferSize == null || bufferSize.length() == 0 ? 0 : Integer.parseInt(bufferSize);
081            } catch (final NumberFormatException e) {
082                LOGGER.warn("Buffer size [" + bufferSize + "] not an integer, using no buffer.");
083                bufferSizeInt = 0;
084            }
085    
086            final boolean handleExceptions = suppressExceptions == null || !Boolean.parseBoolean(suppressExceptions);
087    
088            try {
089                @SuppressWarnings("unchecked")
090                final Class<? extends AbstractLogEventWrapperEntity> entityClass =
091                        (Class<? extends AbstractLogEventWrapperEntity>) Class.forName(entityClassName);
092    
093                if (!AbstractLogEventWrapperEntity.class.isAssignableFrom(entityClass)) {
094                    LOGGER.error("Entity class [{}] does not extend AbstractLogEventWrapperEntity.", entityClassName);
095                    return null;
096                }
097    
098                try {
099                    entityClass.getConstructor();
100                } catch (final NoSuchMethodException e) {
101                    LOGGER.error("Entity class [{}] does not have a no-arg constructor. The JPA provider will reject it.",
102                            entityClassName);
103                    return null;
104                }
105    
106                final Constructor<? extends AbstractLogEventWrapperEntity> entityConstructor =
107                        entityClass.getConstructor(LogEvent.class);
108    
109                final String managerName = "jpaManager{ description=" + name + ", bufferSize=" + bufferSizeInt
110                        + ", persistenceUnitName=" + persistenceUnitName + ", entityClass=" + entityClass.getName() + "}";
111    
112                final JPADatabaseManager manager = JPADatabaseManager.getJPADatabaseManager(
113                        managerName, bufferSizeInt, entityClass, entityConstructor, persistenceUnitName
114                );
115                if (manager == null) {
116                    return null;
117                }
118    
119                return new JPAAppender(name, filter, handleExceptions, manager);
120            } catch (final ClassNotFoundException e) {
121                LOGGER.error("Could not load entity class [{}].", entityClassName, e);
122                return null;
123            } catch (final NoSuchMethodException e) {
124                LOGGER.error("Entity class [{}] does not have a constructor with a single argument of type LogEvent.",
125                        entityClassName);
126                return null;
127            }
128        }
129    }