Package org.apache.juneau.microservice.logging

Class LogEntryFormatter

java.lang.Object

java.util.logging.Formatter

org.apache.juneau.microservice.logging.LogEntryFormatter

public class LogEntryFormatter
extends Formatter

Log entry formatter.

Uses three simple parameter for configuring log entry formats:

• dateFormat - A SimpleDateFormat string describing the format for dates.
• format - A string with {...} replacement variables representing predefined fields.
• useStackTraceHashes - A setting that causes duplicate stack traces to be replaced with 8-character hash strings.

This class converts the format strings into a regular expression that can be used to parse the resulting log file.

Constructor Summary

Constructors

Constructor	Description
LogEntryFormatter(String format, String dateFormat, boolean useStackTraceHashes)	Create a new formatter.

Method Summary

Modifier and Type	Method	Description
String	format(LogRecord r)
DateFormat	getDateFormat()	Returns the DateFormat used for matching dates.
String	getField(String fieldName, Matcher m)	Given a matcher that has matched the pattern specified by getLogEntryPattern(), returns the field value from the match.
Pattern	getLogEntryPattern()	Returns the regular expression pattern used for matching log entries.

Methods inherited from class java.util.logging.Formatter

formatMessage, getHead, getTail

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

LogEntryFormatter

public LogEntryFormatter(String format,
 String dateFormat,
 boolean useStackTraceHashes)

Create a new formatter.

Parameters:

format - The log entry format. e.g. "[{date} {level}] {msg}%n" The string can contain any of the following variables:

1. "{date}" - The date, formatted per "Logging/dateFormat".
2. "{class}" - The class name.
3. "{method}" - The method name.
4. "{logger}" - The logger name.
5. "{level}" - The log level name.
6. "{msg}" - The log message.
7. "{threadid}" - The thread ID.
8. "{exception}" - The localized exception message.
9. "{traceId}" - The active OpenTelemetry trace ID (empty when OTel is absent or no span is active).
10. "{spanId}" - The active OpenTelemetry span ID (empty when OTel is absent or no span is active).

Must not be null.

dateFormat - The SimpleDateFormat format to use for dates. e.g. "yyyy.MM.dd hh:mm:ss".
Must not be null.

useStackTraceHashes - If true, only print unique stack traces once and then refer to them by a simple 8 character hash identifier.

Method Details

format

public String format(LogRecord r)

Specified by:

format in class Formatter

getDateFormat

public DateFormat getDateFormat()

Returns the DateFormat used for matching dates.

Returns a defensive clone because SimpleDateFormat is mutable and not thread-safe; each caller gets its own instance and cannot corrupt the formatter's shared internal state.

Returns:

A clone of the DateFormat used for matching dates.

getField

public String getField(String fieldName,
 Matcher m)

Given a matcher that has matched the pattern specified by getLogEntryPattern(), returns the field value from the match.

Parameters:

fieldName - The field name. Possible values are:

• "date"
• "class"
• "method"
• "logger"
• "level"
• "msg"
• "threadid"
• "exception"
• "traceId"
• "spanId"

m - The matcher. Must not be null.

Returns:

The field value, or null if the specified field does not exist.

getLogEntryPattern

public Pattern getLogEntryPattern()

Returns the regular expression pattern used for matching log entries.

Returns:

The regular expression pattern used for matching log entries.