org.plumelib.bcelutil

Class SimpleLog

java.lang.Object

org.plumelib.bcelutil.SimpleLog

public final class SimpleLog
extends Object

A logging class with the following features:

• Can be enabled and disabled (when disabled, all operations are no-ops),
• Can indent/exdent log output,
• Writes to a file or to standard output, and
• Can provide a stack trace.

Field Summary

Fields

Modifier and Type	Field and Description
boolean	enabled If false, do no output.
private @Nullable String	filename The file for logging output.
private String	INDENT_STR_ONE_LEVEL Indentation string for one level of indentation.
private int	indentLevel The current indentation level.
private @Nullable String	indentString Cache for the current indentation string, or null if needs to be recomputed.
private List<String>	indentStrings Cache of indentation strings that have been computed so far.
private @MonotonicNonNull PrintStream	logfile Where to write logging output.

Constructor Summary

Constructors

Constructor and Description
SimpleLog() Create a new SimpleLog object with logging to standard out enabled.
SimpleLog(boolean enabled) Create a new SimpleLog object with logging to standard out.
SimpleLog(@Nullable String filename) Create a new SimpleLog object with logging to a file enabled.
SimpleLog(@Nullable String filename, boolean enabled) Create a new SimpleLog object with logging to a file.

Method Summary

Modifier and Type	Method and Description
boolean	enabled() Return whether logging is enabled.
void	exdent() Decreases indentation by one level.
private String	getIndentString() Return the current indentation string.
void	indent() Increases indentation by one level.
void	log(String format, Object... args) Log a message.
void	logStackTrace() Print a stack trace to the log.
void	resetIndent() Resets indentation to none.
private void	setLogfile() Set the private field logfile, based on the private field filename.

Methods inherited from class java.lang.Object

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

Field Detail

enabled

public boolean enabled

If false, do no output.

logfile

private @MonotonicNonNull PrintStream logfile

Where to write logging output. Null if nothing has been output yet.

filename

private @Nullable String filename

The file for logging output. If null, System.out is used.

indentLevel

private int indentLevel

The current indentation level.

INDENT_STR_ONE_LEVEL

private final String INDENT_STR_ONE_LEVEL

Indentation string for one level of indentation.

See Also:

Constant Field Values

indentString

private @Nullable String indentString

Cache for the current indentation string, or null if needs to be recomputed. Never access this directly; always call getIndentString().

indentStrings

private List<String> indentStrings

Cache of indentation strings that have been computed so far.

Constructor Detail

SimpleLog

public SimpleLog()

Create a new SimpleLog object with logging to standard out enabled.

SimpleLog

public SimpleLog(boolean enabled)

Create a new SimpleLog object with logging to standard out.

Parameters:

enabled - whether the logger starts out enabled

SimpleLog

public SimpleLog(@Nullable String filename)

Create a new SimpleLog object with logging to a file enabled.

Parameters:

filename - file name, or use "-" or null for System.out

SimpleLog

public SimpleLog(@Nullable String filename,
                 boolean enabled)

Create a new SimpleLog object with logging to a file.

Parameters:

filename - file name, or use "-" or null for System.out

enabled - whether the logger starts out enabled

Method Detail

enabled

public boolean enabled()

Return whether logging is enabled.

Returns:

whether logging is enabled

setLogfile

@EnsuresNonNull(value="logfile")
private void setLogfile()

Set the private field logfile, based on the private field filename.

This creates the file if it does not exist. This should be called lazily, when output is performed. Otherwise, it would be annoying to create a zero-size logfile if no output is ever written.

log

@FormatMethod
public void log(String format,
                              Object... args)

Log a message. The message is prepended with the current indentation string. The indentation is only applied at the start of the message, not for every line break within the message.

Parameters:

format - format string for message

args - values to be substituted into format

logStackTrace

public void logStackTrace()

Print a stack trace to the log.

getIndentString

private String getIndentString()

Return the current indentation string.

Returns:

the current indentation string

indent

public void indent()

Increases indentation by one level.

exdent

public void exdent()

Decreases indentation by one level.

resetIndent

public void resetIndent()

Resets indentation to none. Has no effect if logging is disabled.