import org.apache.logging.log4j.core.Filter; impor...

# codereview

[Dalinar]

import org.apache.logging.log4j.core.Filter;
import org.apache.logging.log4j.core.Layout;
import org.apache.logging.log4j.core.LogEvent;
import org.apache.logging.log4j.core.appender.AbstractAppender;
import org.apache.logging.log4j.core.appender.AppenderLoggingException;
import org.apache.logging.log4j.core.config.plugins.Plugin;
import org.apache.logging.log4j.core.config.plugins.PluginAttribute;
import org.apache.logging.log4j.core.config.plugins.PluginElement;
import org.apache.logging.log4j.core.config.plugins.PluginFactory;
import org.apache.logging.log4j.core.layout.PatternLayout;

import java.io.Serializable;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;

/**
* <h2>AnsiConsoleAppender</h2>
*
* <h3>notes</h3>
* <li>class name need not match the @Plugin name</li>
* <h3>more<h3/>
* <li><a href="https://stackoverflow.com/a/24220688/270143">How to Create a Custom Appender in log4j2?</a></li>
*/
@Plugin(name="AnsiConsoleAppender", category="Core", elementType="appender", printObject=true)
public final class AnsiConsoleAppender extends AbstractAppender {

private final ReadWriteLock rwLock = new ReentrantReadWriteLock();
private final Lock readLock = rwLock.readLock();

protected AnsiConsoleAppender(String name, Filter filter,
Layout<? extends Serializable> layout, final boolean ignoreExceptions) {
super(name, filter, layout, ignoreExceptions);
}

// The append method is where the appender does the work.
// Given a log event, you are free to do with it what you want.
// This example demonstrates:
// 1. Concurrency: this method may be called by multiple threads concurrently
// 2. How to use layouts
// 3. Error handling
//@Override
public void append(LogEvent event) {
try {
final byte[] bytes = getLayout().toByteArray(event);
System.out.write("YO: ".getBytes());
System.out.write(bytes);
} catch (Exception ex) {
if (!ignoreExceptions()) throw new AppenderLoggingException(ex);
}
}

// Your custom appender needs to declare a factory method
// annotated with @PluginFactory. Log4j will parse the configuration
// and call this factory method to construct an appender instance with
// the configured attributes.
@PluginFactory
public static AnsiConsoleAppender createAppender(
@PluginAttribute("name") String name,
@PluginElement("Layout") Layout<? extends Serializable> layout,
@PluginElement("Filter") final Filter filter,
@PluginAttribute("otherAttribute") String otherAttribute) {
if (name == null) {
LOGGER.error("No name provided for AnsiConsoleAppenderImpl");
return null;
}
if (layout == null) {
layout = PatternLayout.createDefaultLayout();
}
return new AnsiConsoleAppender(name, filter, layout, true);
}
}

[rook]

Hey man, just as an aside, I wanted to draw your attention to the + to the left of the text entry in Slack. If you click that and click Code or text snippet, you can paste your code there and it will receive syntax highlighting and be collapsible. It helps a lot in workspaces with a large number of people to be able to collapse large code posts to improve readability.