No4J

Simple logging library with sane defaults

Supports:

• Level hierarchy, including custom levels
• Console output separation between STDERR and STDOUT depending on severity
• File output
• Rolling appender with file compression
• Basic inheritance
• ANSI color printing
• Logging per site as an extension

Configuration and properties

The configuration file follows INI format:

[symbolic-name]
name = org.some.package
level = ERROR
max_length = 10000
date_zone = UTC+6
file_out = main.package.log
file_enabled = true
file_rolling_size=1048576
file_rolling_enabled=false

[mongodb]
name = org.nosql.impl
inherit = main.package

Each logger declaration has its own symbolic name enclosed in square brackets.
Every key is followed by = followed by value. Two key-value pairs are not allowed on the same line.
Values are not enclosed in quotation marks. Comments are allowed but must be preceded with a #.
The order of declarations does not matter. Only single-level inheritance is allowed, and it is performed in no particular order. The config file no4j.ini must be in the root directory of the project or in src/main/resources. To prevent collisions, the configuration does not inherit properties such as the file output path.

Configuration keys:

Key	Meaning	Default value	Type
name	logger name		String
level	logging level	OFF	Level
max_length	cap log message length	Integer.MAX_Value - 32	int
max_stack_trace_depth	max stack trace depth in log message	64	int
level_padding	desired level length in log message	14	int
method_padding	desired method length in log message	30	int
include_method	include method in log message	true	boolean
include_line_number	include line number in log message	true	boolean
include_package	include package prefix in log message	false	boolean
stderr_level	STDERR logging level	ERROR	Level
file_out	log file path	null	Path
file_rolling_size	file size to reach before rolling	4194304	long
file_enabled	write logs to file	false	boolean
file_rolling_enabled	roll log files	false	boolean
console_enabled	write to console	true	boolean
date_pattern	date format pattern	yyyy-MM-dd HH:mm:ss	DateTimeFormatter
date_zone	UTC/GMT/UT zone	UTC+0	ZoneId
inherit	symbolic logger name to inherit from	N/A	N/A

Initializing by loading the configuration file

import no4j.core.No4JConfiguration;

class Test {
    public static void main(String[] args) {
        try {
            No4JConfiguration.configure();
        } catch (IOException e) {
            /* Handle exception */
        }
    }
}

Configuring programmatically

import no4j.core.FileAppender;
import no4j.core.Level;
import no4j.core.Logger;
import no4j.extensions.LoggerBuilder;

class Test {
    public static void main(String[] args) {
        Logger log = LoggerBuilder.error("main.package")
                .file("main.package.log")
                .rollAtMegabytes(2)
                .maxMessageLength(5000)
                .getLogger();

        // USAGE
        log.debug("DEBUG");
        log.info("INFO");
        log.warn("WARNING");
        log.fatal("FATAL");
        log.unreachable("UNREACHABLE");
        log.exception(new RuntimeException("Exception thrown!"));
    }
}

ANSI color support

Generally supported within all Linux terminals

Windows cmd or powershell generally do not support ANSI. It is possible to enable ANSI in Windows 10 and later by creating a DWORD(32-bit) VirtualTerminalLevel with value 1 at HKEY_CURRENT_USER\Console in registry

Alternative terminals for Windows that support ANSI

• Git Bash
• Cmder
• IntelliJ console

Jitpack import

Maven

<dependency>
    <groupId>com.github.FriskIsGit</groupId>
    <artifactId>no4j-logger</artifactId>
    <version>main-SNAPSHOT</version>
</dependency>

By default, all POMs implicitly inherit from a super-POM: https://maven.apache.org/ref/3.0.4/maven-model-builder/super-pom.html When an external repository is specified the default repository needs to be respecified:

<repositories>
    <repository>
        <id>jitpack.io</id>
        <url>https://jitpack.io</url>
    </repository>

    <repository>
        <id>central</id>
        <name>Central Repository</name>
        <url>https://maven.org/maven2</url>
    </repository>
</repositories>

Gradle

Include at root level in build.gradle at the end of repositories:

dependencyResolutionManagement {
    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
    repositories {
        mavenCentral()
        maven { url 'https://jitpack.io' }
    }
}

Add the dependency:

dependencies {
    implementation 'com.github.FriskIsGit:no4j-logger:main-SNAPSHOT'
}