assertArgumentNotNull("clazz", clazz);

        if (!initialized) {
            initialize();
        }
        Logger logger = loggers.get(clazz);
        if (logger == null) {
            logger = new Logger(clazz);
            loggers.put(clazz, logger);
        }
        return logger;
    }

    /**
     * フォーマットされたメッセージ文字列を返します。
     *
     * @param messageCode

			<DefaultRolloverStrategy fileIndex="max" min="1"
				max="${backup.max.history}" compressionLevel="9" />
		</RollingFile>
		<Rewrite name="AppFile">
			<AppenderRef ref="AppRollingFile" />
			<ErrorToWarnRewritePolicy loggers="org.apache.fontbox,org.apache.pdfbox,org.apache.poi" />
		</Rewrite>
		<RollingFile name="StatsFile" fileName="${log.file.basedir}/fess-urls.log"
			filePattern="${log.file.basedir}/fess-urls${backup.date.suffix}-%i.log.gz">

				max="${backup.max.history}" compressionLevel="9" />
		</RollingFile>
	</Appenders>

	<Loggers>
		<Logger name="org.codelibs.fess" additivity="false" level="${log.level}">
			<AppenderRef ref="AppFile" />
		</Logger>
		<Root level="${root.log.level}">
			<AppenderRef ref="AppFile" />
		</Root>
	</Loggers>

					<IfFileName glob="searchlog*.log.gz" />
					<IfLastModified age="P${backup.searchlog.max.age}D" />
				</Delete>
			</DefaultRolloverStrategy>
		</RollingFile>
	</Appenders>

	<Loggers>
		<Logger name="org.codelibs" additivity="false" level="${log.level}">
			<AppenderRef ref="AppFile" />
		</Logger>
		<Logger name="org.dbflute" additivity="false" level="${log.level}">
			<AppenderRef ref="AppFile" />

            }
        }
        return event;
    }

    @PluginFactory
    public static ErrorToWarnRewritePolicy createPolicy(@PluginAttribute("loggers") final String loggerNamePrefix) {
        final String[] loggerNames = loggerNamePrefix != null
                ? Arrays.stream(loggerNamePrefix.split(",")).map(String::trim).filter(s -> s.length() > 0).toArray(n -> new String[n])

				max="${backup.max.history}" compressionLevel="9" />
		</RollingFile>
	</Appenders>

	<Loggers>
		<Logger name="org.codelibs.fess" additivity="false" level="${log.level}">
			<AppenderRef ref="AppFile" />
		</Logger>
		<Root level="${root.log.level}">
			<AppenderRef ref="AppFile" />
		</Root>
	</Loggers>