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package java.util.logging;
import java.io.*;
import java.time.ZoneId;
import java.time.ZonedDateTime;
import jdk.internal.logger.SurrogateLogger;
/**
* Print a brief summary of the {@code LogRecord} in a human readable
* format. The summary will typically be 1 or 2 lines.
*
* <p>
* <a name="formatting">
* <b>Configuration:</b></a>
* The {@code SimpleFormatter} is initialized with the
* <a href="../Formatter.html#syntax">format string</a>
* specified in the {@code java.util.logging.SimpleFormatter.format}
* property to {@linkplain #format format} the log messages.
* This property can be defined
* in the {@linkplain LogManager#getProperty logging properties}
* configuration file
* or as a system property. If this property is set in both
* the logging properties and system properties,
* the format string specified in the system property will be used.
* If this property is not defined or the given format string
* is {@linkplain java.util.IllegalFormatException illegal},
* the default format is implementation-specific.
*
* @since 1.4
* @see java.util.Formatter
*/
public class SimpleFormatter extends Formatter {
// format string for printing the log record
static String getLoggingProperty(String name) {
return LogManager.getLogManager().getProperty(name);
}
private final String format =
SurrogateLogger.getSimpleFormat(SimpleFormatter::getLoggingProperty);
/**
* Format the given LogRecord.
* <p>
* The formatting can be customized by specifying the
* <a href="../Formatter.html#syntax">format string</a>
* in the <a href="#formatting">
* {@code java.util.logging.SimpleFormatter.format}</a> property.
* The given {@code LogRecord} will be formatted as if by calling:
* <pre>
* {@link String#format String.format}(format, date, source, logger, level, message, thrown);
* </pre>
* where the arguments are:<br>
* <ol>
* <li>{@code format} - the {@link java.util.Formatter
* java.util.Formatter} format string specified in the
* {@code java.util.logging.SimpleFormatter.format} property
* or the default format.</li>
* <li>{@code date} - a {@link ZonedDateTime} object representing
* {@linkplain LogRecord#getInstant() event time} of the log record
* in the {@link ZoneId#systemDefault()} system time zone.</li>
* <li>{@code source} - a string representing the caller, if available;
* otherwise, the logger's name.</li>
* <li>{@code logger} - the logger's name.</li>
* <li>{@code level} - the {@linkplain Level#getLocalizedName
* log level}.</li>
* <li>{@code message} - the formatted log message
* returned from the {@link Formatter#formatMessage(LogRecord)}
* method. It uses {@link java.text.MessageFormat java.text}
* formatting and does not use the {@code java.util.Formatter
* format} argument.</li>
* <li>{@code thrown} - a string representing
* the {@linkplain LogRecord#getThrown throwable}
* associated with the log record and its backtrace
* beginning with a newline character, if any;
* otherwise, an empty string.</li>
* </ol>
*
* <p>Some example formats:<br>
* <ul>
* <li> {@code java.util.logging.SimpleFormatter.format="%4$s: %5$s [%1$tc]%n"}
* <p>This prints 1 line with the log level ({@code 4$}),
* the log message ({@code 5$}) and the timestamp ({@code 1$}) in
* a square bracket.
* <pre>
* WARNING: warning message [Tue Mar 22 13:11:31 PDT 2011]
* </pre></li>
* <li> {@code java.util.logging.SimpleFormatter.format="%1$tc %2$s%n%4$s: %5$s%6$s%n"}
* <p>This prints 2 lines where the first line includes
* the timestamp ({@code 1$}) and the source ({@code 2$});
* the second line includes the log level ({@code 4$}) and
* the log message ({@code 5$}) followed with the throwable
* and its backtrace ({@code 6$}), if any:
* <pre>
* Tue Mar 22 13:11:31 PDT 2011 MyClass fatal
* SEVERE: several message with an exception
* java.lang.IllegalArgumentException: invalid argument
* at MyClass.mash(MyClass.java:9)
* at MyClass.crunch(MyClass.java:6)
* at MyClass.main(MyClass.java:3)
* </pre></li>
* <li> {@code java.util.logging.SimpleFormatter.format="%1$tb %1$td, %1$tY %1$tl:%1$tM:%1$tS %1$Tp %2$s%n%4$s: %5$s%n"}
* <p>This prints 2 lines similar to the example above
* with a different date/time formatting and does not print
* the throwable and its backtrace:
* <pre>
* Mar 22, 2011 1:11:31 PM MyClass fatal
* SEVERE: several message with an exception
* </pre></li>
* <li> {@code java.util.logging.SimpleFormatter.format="%1$tb %1$td, %1$tY %1$tl:%1$tM:%1$tS.%1$tN %1$Tp %2$s%n%4$s: %5$s%6$s%n"}
* <p>Since JDK 9, {@code java.util.logging} uses {@link
* java.time.Clock#systemUTC() java.time} to create more precise time
* stamps.
* The format above can be used to add a {@code .%1$tN} to the
* date/time formatting so that nanoseconds will also be printed:
* <pre>
* Feb 06, 2015 5:33:10.279216000 PM example.Main main
* INFO: This is a test
* </pre></li>
* </ul>
* <p>This method can also be overridden in a subclass.
* It is recommended to use the {@link Formatter#formatMessage}
* convenience method to localize and format the message field.
*
* @param record the log record to be formatted.
* @return a formatted log record
*/
@Override
public String format(LogRecord record) {
ZonedDateTime zdt = ZonedDateTime.ofInstant(
record.getInstant(), ZoneId.systemDefault());
String source;
if (record.getSourceClassName() != null) {
source = record.getSourceClassName();
if (record.getSourceMethodName() != null) {
source += " " + record.getSourceMethodName();
}
} else {
source = record.getLoggerName();
}
String message = formatMessage(record);
String throwable = "";
if (record.getThrown() != null) {
StringWriter sw = new StringWriter();
PrintWriter pw = new PrintWriter(sw);
pw.println();
record.getThrown().printStackTrace(pw);
pw.close();
throwable = sw.toString();
}
return String.format(format,
zdt,
source,
record.getLoggerName(),
record.getLevel().getLocalizedLevelName(),
message,
throwable);
}
}