log4j-core/src/main/java/org/apache/logging/log4j/core/appender/nosql/NoSqlAppender.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache license, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the license for the specific language governing permissions and
 * limitations under the license.
 */
package org.apache.logging.log4j.core.appender.nosql;

import org.apache.logging.log4j.core.Appender;
import org.apache.logging.log4j.core.Filter;
import org.apache.logging.log4j.core.Layout;
import org.apache.logging.log4j.core.appender.AbstractAppender;
import org.apache.logging.log4j.core.appender.db.AbstractDatabaseAppender;
import org.apache.logging.log4j.core.config.Property;
import org.apache.logging.log4j.plugins.Plugin;
import org.apache.logging.log4j.plugins.PluginBuilderAttribute;
import org.apache.logging.log4j.plugins.PluginElement;
import org.apache.logging.log4j.plugins.PluginFactory;

import java.io.Serializable;

/**
 * This Appender writes logging events to a NoSQL database using a configured NoSQL provider. It requires
 * implementations of {@link NoSqlObject}, {@link NoSqlConnection}, and {@link NoSqlProvider} to "know" how to write
 * events to the chosen NoSQL database.
 * <p>
 * For examples on how to write your own NoSQL provider, see the simple source code for the MongoDB and CouchDB
 * providers.
 * </p>
 *
 * @see NoSqlObject
 * @see NoSqlConnection
 * @see NoSqlProvider
 */
@Plugin(name = "NoSql", category = "Core", elementType = Appender.ELEMENT_TYPE, printObject = true)
public final class NoSqlAppender extends AbstractDatabaseAppender<NoSqlDatabaseManager<?>> {

    /**
     * Builds ConsoleAppender instances.
     *
     * @param <B>
     *            The type to build
     */
    public static class Builder<B extends Builder<B>> extends AbstractAppender.Builder<B>
            implements org.apache.logging.log4j.plugins.util.Builder<NoSqlAppender> {

        @PluginBuilderAttribute("bufferSize")
        private int bufferSize;

        @PluginElement("NoSqlProvider")
        private NoSqlProvider<?> provider;

        @SuppressWarnings("resource")
        @Override
        public NoSqlAppender build() {
            final String name = getName();
            if (provider == null) {
                LOGGER.error("NoSQL provider not specified for appender [{}].", name);
                return null;
            }

            final String managerName = "noSqlManager{ description=" + name + ", bufferSize=" + bufferSize
                    + ", provider=" + provider + " }";

            final NoSqlDatabaseManager<?> manager = NoSqlDatabaseManager.getNoSqlDatabaseManager(managerName,
                    bufferSize, provider);
            if (manager == null) {
                return null;
            }

            return new NoSqlAppender(name, getFilter(), getLayout(), isIgnoreExceptions(), getPropertyArray(), manager);
        }

        /**
         * Sets the buffer size.
         *
         * @param bufferSize
         *            If an integer greater than 0, this causes the appender to buffer log events and flush whenever the
         *            buffer reaches this size.
         * @return this
         */
        public B setBufferSize(final int bufferSize) {
            this.bufferSize = bufferSize;
            return asBuilder();
        }

        /**
         * Sets the provider.
         *
         * @param provider
         *            The NoSQL provider that provides connections to the chosen NoSQL database.
         * @return this
         */
        public B setProvider(final NoSqlProvider<?> provider) {
            this.provider = provider;
            return asBuilder();
        }
    }

    @PluginFactory
    public static <B extends Builder<B>> B newBuilder() {
        return new Builder<B>().asBuilder();
    }

    private final String description;

    private NoSqlAppender(final String name, final Filter filter, final Layout<? extends Serializable> layout,
            final boolean ignoreExceptions, final Property[] properties, final NoSqlDatabaseManager<?> manager) {
        super(name, filter, layout, ignoreExceptions, properties, manager);
        this.description = this.getName() + "{ manager=" + this.getManager() + " }";
    }

    @Override
    public String toString() {
        return this.description;
    }
}