log4j-csv/src/main/java/org/apache/logging/log4j/csv/layout/CsvParameterLayout.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.csv.layout;

import java.io.IOException;
import java.nio.charset.Charset;

import org.apache.commons.csv.CSVFormat;
import org.apache.commons.csv.QuoteMode;
import org.apache.logging.log4j.core.Layout;
import org.apache.logging.log4j.core.LogEvent;
import org.apache.logging.log4j.core.config.Configuration;
import org.apache.logging.log4j.plugins.Node;
import org.apache.logging.log4j.plugins.Plugin;
import org.apache.logging.log4j.plugins.PluginAttribute;
import org.apache.logging.log4j.core.config.plugins.PluginConfiguration;
import org.apache.logging.log4j.plugins.PluginFactory;
import org.apache.logging.log4j.message.Message;
import org.apache.logging.log4j.status.StatusLogger;

/**
 * A Comma-Separated Value (CSV) layout to log event parameters.
 * The event message is currently ignored. 
 * 
 * <p>
 * Best used with:
 * </p>
 * <p>
 * {@code logger.debug(new ObjectArrayMessage(1, 2, "Bob"));}
 * </p>
 * 
 * Depends on Apache Commons CSV 1.4.
 * 
 * @since 2.4
 */
@Plugin(name = "CsvParameterLayout", category = Node.CATEGORY, elementType = Layout.ELEMENT_TYPE, printObject = true)
public class CsvParameterLayout extends AbstractCsvLayout {

    public static AbstractCsvLayout createDefaultLayout() {
        return new CsvParameterLayout(null, Charset.forName(DEFAULT_CHARSET), CSVFormat.valueOf(DEFAULT_FORMAT), null, null);
    }

    public static AbstractCsvLayout createLayout(final CSVFormat format) {
        return new CsvParameterLayout(null, Charset.forName(DEFAULT_CHARSET), format, null, null);
    }

    @PluginFactory
    public static AbstractCsvLayout createLayout(
            // @formatter:off
            @PluginConfiguration final Configuration config,
            @PluginAttribute(defaultString = DEFAULT_FORMAT) final String format,
            @PluginAttribute final Character delimiter,
            @PluginAttribute final Character escape,
            @PluginAttribute final Character quote,
            @PluginAttribute final QuoteMode quoteMode,
            @PluginAttribute final String nullString,
            @PluginAttribute final String recordSeparator,
            @PluginAttribute(defaultString = DEFAULT_CHARSET) final Charset charset,
            @PluginAttribute final String header,
            @PluginAttribute final String footer)
            // @formatter:on
    {

        final CSVFormat csvFormat = createFormat(format, delimiter, escape, quote, quoteMode, nullString, recordSeparator);
        return new CsvParameterLayout(config, charset, csvFormat, header, footer);
    }

    public CsvParameterLayout(final Configuration config, final Charset charset, final CSVFormat csvFormat, final String header, final String footer) {
        super(config, charset, csvFormat, header, footer);
    }

    @Override
    public String toSerializable(final LogEvent event) {
        final Message message = event.getMessage();
        final Object[] parameters = message.getParameters();
        final StringBuilder buffer = getStringBuilder();
        try {
            getFormat().printRecord(buffer, parameters);
            return buffer.toString();
        } catch (final IOException e) {
            StatusLogger.getLogger().error(message, e);
            return getFormat().getCommentMarker() + " " + e;
        }
    }

}