Lombok and Slf4j

I already talked  a bit about Slf4j, as a recommended interface to any implementor logger.

I have already talked about Lombok, and the fantastic way it creates java bytecode in compile time in order to make you safe some time.

Now let's reduce the time and code we need in almost every class:
private static final org.slf4j.Logger log = org.slf4j.LoggerFactory.getLogger(LogExample.class);
with:
@Slf4j

That's all, put that annotation in your class, and you'll have your logger, with name "log", referring that class, and using Slf4j interface. Simply perfect ;)

If you are still a log4j lover, or maybe for other loggers, Lombok provides these annotations:

@CommonsLog
Creates private static final org.apache.commons.logging.Log log = org.apache.commons.logging.LogFactory.getLog(LogExample.class);
@Log
Creates private static final java.util.logging.Logger log = java.util.logging.Logger.getLogger(LogExample.class.getName());
@Log4j
Creates private static final org.apache.log4j.Logger log = org.apache.log4j.Logger.getLogger(LogExample.class);

More information here!

See you soon..

Lombok, cleaning up your code

Much time without writing, ok, I have been working hard in company projects a bit, and the rest of the time trying to improve our tools and processes.

I want to introduce you to "Lombok", a nice tool that could bring light to the darkness of certain classes everyone has seen at least once.

The gain in this case is almost out of discussion, you annotate your code and magically it gets powers and kicks the ass to the bad guys. They are not dependencies and either aspects, because Lombok works in compilation time almost always. Indeed, inclusion of lombok.jar is not necessary in all cases, a few ones doesn't need it.


Some examples from their web:

@Getter and @Setter, it is like using Eclipse "generate getter and setter automatically" but Lombok does even easier and cleaner:

import lombok.AccessLevel;  import lombok.Getter;  import lombok.Setter;    public class GetterSetterExample {    @Getter @Setter private int age = 10;    @Setter(AccessLevel.PROTECTED) private String name;        @Override public String toString() {      return String.format("%s (age: %d)", name, age);    }  }

turns in

public class GetterSetterExample {    private int age = 10;    private String name;        @Override public String toString() {      return String.format("%s (age: %d)", name, age);    }        public int getAge() {      return age;    }        public void setAge(int age) {      this.age = age;    }        protected void setName(String name) {      this.name = name;    }  }

Those changes are made in compiled bytecode, although you can decompile this changes (delombok) and see them in Java.

Another example, let's avoid the tricky and ugly closing file even inside and exception catch.

import lombok.Cleanup;  import java.io.*;    public class CleanupExample {    public static void main(String[] args) throws IOException {      @Cleanup InputStream in = new FileInputStream(args[0]);      @Cleanup OutputStream out = new FileOutputStream(args[1]);      byte[] b = new byte[10000];      while (true) {        int r = in.read(b);        if (r == -1) break;        out.write(b, 0, r);      }    }  }

turns in

import java.io.*;    public class CleanupExample {    public static void main(String[] args) throws IOException {      InputStream in = new FileInputStream(args[0]);      try {        OutputStream out = new FileOutputStream(args[1]);        try {          byte[] b = new byte[10000];          while (true) {            int r = in.read(b);            if (r == -1) break;            out.write(b, 0, r);          }        } finally {          if (out != null) {            out.close();          }        }      } finally {        if (in != null) {          in.close();        }      }    }  }

More: automatic log declaration

import lombok.extern.slf4j.Log;    @Log  public class LogExample {        public static void main(String... args) {      log.error("Something's wrong here");    }  }    @Log(java.util.List.class)  public class LogExampleOther {        public static void main(String... args) {      log.warn("Something might be wrong here");    }  }

turns in

public class LogExample {    private static final org.slf4j.Logger log = org.slf4j.LoggerFactory.getLogger(LogExample.class);        public static void main(String... args) {      log.error("Something's wrong here");    }  }    public class LogExampleOther {    private static final org.slf4j.Logger log = org.slf4j.LoggerFactory.getLogger(java.util.List.class);        public static void main(String... args) {      log.warn("Something might be wrong here");    }  }

(Several implementations of log are provided).

And so on and on... check the features list

http://projectlombok.org/features/index.html

This tool is also integrated with Eclipse (through installation) and Eclipse (only by including it as a dependency). Use it wisely, but use it :)