Package io.spine.logging.flogger.backend

Class BaseMessageFormatter

java.lang.Object

io.spine.logging.flogger.parser.MessageBuilder<StringBuilder>

io.spine.logging.flogger.backend.BaseMessageFormatter

All Implemented Interfaces:

ParameterVisitor

public class BaseMessageFormatter
extends MessageBuilder<StringBuilder>
implements ParameterVisitor

The default formatter for log messages and arguments.

This formatter can be overridden to modify the behaviour of the ParameterVisitor methods, but this is not expected to be common. Most logger backends will only ever need to use appendFormattedMessage(LogData, StringBuilder).

See Also:

Original Java code of Google Flogger

Field Summary

Fields

Modifier and Type	Field	Description
protected Object[]	args
protected StringBuilder	out

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	BaseMessageFormatter(TemplateContext context, Object[] args, StringBuilder out)

Method Summary

Modifier and Type	Method	Description
void	addParameterImpl(int termStart, int termEnd, Parameter param)	Adds the specified parameter to the format instance currently being built.
static StringBuilder	appendFormattedMessage(LogData data, StringBuilder out)	Appends the formatted log message of the given log data to the given buffer.
StringBuilder	buildImpl()	Returns the implementation specific result of parsing the current log message.
void	visit(Object value, FormatChar format, FormatOptions options)	Visits a log message argument with formatting specified by %s, %d etc...
void	visitDateTime(Object value, DateTimeFormat format, FormatOptions options)	Visits a date/time log message argument with formatting specified by %t or similar.
void	visitMissing()	Visits a missing argument.
void	visitNull()	Visits a null argument.
void	visitPreformatted(Object value, String formatted)	Visits a log message argument for which formatting has already occurred.

Methods inherited from class io.spine.logging.flogger.parser.MessageBuilder

addParameter, build, getExpectedArgumentCount, getMessage, getParser

Methods inherited from class java.lang.Object

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

Field Detail

args

protected final Object[] args

out

protected final StringBuilder out

Constructor Detail

BaseMessageFormatter

protected BaseMessageFormatter(TemplateContext context,
                               Object[] args,
                               StringBuilder out)

Method Detail

appendFormattedMessage

@CanIgnoreReturnValue
public static StringBuilder appendFormattedMessage(LogData data,
                                                   StringBuilder out)

Appends the formatted log message of the given log data to the given buffer.

Note that the LogData need not have a template context or arguments, it might just have a literal argument, which will be appended without additional formatting.

Parameters:

data - the log data with the message to be appended.

out - a buffer to append to.

Returns:

the given buffer (for method chaining).

addParameterImpl

public void addParameterImpl(int termStart,
                             int termEnd,
                             Parameter param)

Description copied from class: MessageBuilder

Adds the specified parameter to the format instance currently being built. This method is to signify that the parsing of the next parameter is complete.

Note that each successive call to this method during parsing will specify a disjoint ranges of characters from the log message and that each range will be higher that the previously specified one.

Specified by:

addParameterImpl in class MessageBuilder<StringBuilder>

Parameters:

termStart - the index of the first character in the log message string that was parsed to form the given parameter.

termEnd - the index after the last character in the log message string that was parsed to form the given parameter.

param - a parameter representing the format specified by the substring of the log message in the range [termStart, termEnd).

buildImpl

public StringBuilder buildImpl()

Description copied from class: MessageBuilder

Returns the implementation specific result of parsing the current log message.

Specified by:

buildImpl in class MessageBuilder<StringBuilder>

visit

public void visit(Object value,
                  FormatChar format,
                  FormatOptions options)

Description copied from interface: ParameterVisitor

Visits a log message argument with formatting specified by %s, %d etc...

Note that this method may still visit arguments which represent date/time values if the format is not explicit (e.g. log("time=%s", dateTime)).

Specified by:

visit in interface ParameterVisitor

Parameters:

value - the non-null log message argument.

format - the printf format specifier.

options - formatting options.

visitDateTime

public void visitDateTime(Object value,
                          DateTimeFormat format,
                          FormatOptions options)

Description copied from interface: ParameterVisitor

Visits a date/time log message argument with formatting specified by %t or similar.

Note that because this method is called based on the specified format (and not the argument type) it may visit arguments whose type is not a known date/time value. This is necessary to permit new date/time types to be supported by different logging backends (e.g. JodaTime).

Specified by:

visitDateTime in interface ParameterVisitor

Parameters:

value - the non-null log message argument.

format - the date/time format specifier.

options - formatting options.

visitPreformatted

public void visitPreformatted(Object value,
                              String formatted)

Description copied from interface: ParameterVisitor

Visits a log message argument for which formatting has already occurred. This method is only invoked when non-printf message formatting is used (e.g. brace style formatting).

This method is intended for use by Parameter implementations which describe formatting rules which cannot by represented by either FormatChar or DateTimeFormat. This method discards formatting and type information, and the visitor implementation may choose to reexamine the type of the original argument if doing structural logging.

Specified by:

visitPreformatted in interface ParameterVisitor

Parameters:

value - the original non-null log message argument.

formatted - the formatted representation of the argument

visitMissing

public void visitMissing()

Description copied from interface: ParameterVisitor

Visits a missing argument. This method is called when there is no corresponding value for the parameter's argument index.

Specified by:

visitMissing in interface ParameterVisitor

visitNull

public void visitNull()

Description copied from interface: ParameterVisitor

Visits a null argument.

Specified by:

visitNull in interface ParameterVisitor