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== Summary == | |||
Have you ever wondered how much cleaner your code would look if it weren't littered with all that logging code? And, when you're hunting bugs in production environments, do you produce tons of logging output, but often find that the critical bit of information that you need is missing? | Have you ever wondered how much cleaner your code would look, if it weren't littered with all that logging code? And, when you're hunting bugs in production environments, do you produce tons of logging output, but often find that the critical bit of information that you need is missing? | ||
If the answers are "no" and "no", then stop reading. Otherwise, LOGGIFIER may be the tool you need. | If the answers are "no" and "no", then stop reading. Otherwise, LOGGIFIER may be the tool you need. | ||
== | == Getting started == | ||
I presume that you know what <code>java.util.logging</code> is and why you want to use logging at all (e.g. in favor of an interactive debugger). | |||
So let's start with a very simple program: | |||
= | '''import''' java.util.logging.Logger; | ||
'''public class''' Main { | |||
'''private static final''' Logger LOGGER = Logger.getLogger("Main.USER"); | |||
'''public static void''' main(String[] args) { | |||
System.out.println("HELLO WORLD"); | |||
LOGGER.fine("About to terminate"); | |||
} | |||
} | |||
By default, java.util.logging is disabled, so we don't get any logging output: | |||
'''$ javac Main.java''' | |||
'''$ java Main''' | |||
HELLO WORLD | |||
'''$''' | |||
To enable logging, we need to create one more file | |||
# File 'my_logging.properties'. | |||
handlers = java.util.logging.ConsoleHandler | |||
java.util.logging.ConsoleHandler.formatter = java.util.logging.SimpleFormatter | |||
java.util.logging.ConsoleHandler.level = FINEST | |||
java.util.logging.SimpleFormatter.format = [%2$20s] %4$s: %5$s%n | |||
.level = FINEST | |||
, and run our program with the <code>java.util.logging.config.file</code> system property set: | |||
'''$ java -Djava.util.logging.config.file=my_logging.properties Main''' | |||
HELLO WORLD | |||
<span style="color:red;">[ Main main] FINE: About to terminate</span> | |||
'''$''' | |||
So now let's loggify the 'Main' class! Get 'de.unkrig.loggifier.jar' and 'de.unkrig.loggifier-runtime.jar' from [http://loggifier.unkrig.de/download/] and run: | |||
'''$ ls -l''' | |||
-rwx------+ 1 aunkrig users 969 Aug 26 11:23 Main.class | |||
'''$ java -cp de.unkrig.loggifier.jar de.unkrig.loggifier.Main Main.class''' | |||
'''$ ls -l''' | |||
-rwx------+ 1 aunkrig users 2314 Aug 26 11:23 Main.class | |||
'''$''' | |||
Not only can you pass class files to LOGGIFER, but also directories, files in ZIP format that contain '.class' files | |||
(e.g. JAR and WAR files), and even ZIP files that contain nested ZIP files with '.class' files (e.g. EAR files). In | |||
any case, LOGGIFIER will modify the contained '.class' "in-place". | |||
Now what logging do we get now? | |||
'''$ java -Djava.util.logging.config.file=my_logging.properties -cp de.unkrig.loggifier-runtime.jar\;. Main''' | |||
<span style="color:red;">[ Main <clinit>()] FINER: (Main.java:6) ENTRY args=()</span> | |||
<span style="color:red;">[ Main <clinit>()] FINER: (Main.java:6) RETURN</span> | |||
<span style="color:red;">[ Main main(String[])] FINER: (Main.java:9) ENTRY args=(args=String[0])</span> | |||
HELLO WORLD | |||
<span style="color:red;">[ Main main] FINE: About to terminate</span> | |||
<span style="color:red;">[ Main main(String[])] FINER: (Main.java:12) RETURN</span> | |||
'''$''' | |||
Notice that you now need to have the (very small) 'de.unkrig.loggifier-runtime.jar' on the class path, because the | |||
injected logging code needs that. | |||
By default, LOGGIFIER injects a 'reasonable' amount of logging: You can see how the class initializer of the 'Main' class is executed, then the 'main()' method. Notice how the hand-written logging seamlessly mixes with the automatically injected logging. | |||
Effectively, we can now remove the hand-written logging code from our class, because the automatically injected logging | |||
code now does the job: | |||
'''public class''' Main { | |||
'''public static void''' main(String[] args) { | |||
System.out.println("HELLO WORLD"); | |||
} | |||
} | |||
Now let's compile, loggify and run again: | |||
=== | '''$ java -Djava.util.logging.config.file=my_logging.properties -cp de.unkrig.loggifier-runtime.jar\;. Main''' | ||
<span style="color:red;">[ Main <clinit>()] FINER: (Main.java:6) ENTRY args=()</span> | |||
<span style="color:red;">[ Main <clinit>()] FINER: (Main.java:6) RETURN</span> | |||
<span style="color:red;">[ Main main(String[])] FINER: (Main.java:9) ENTRY args=(args=String[0])</span> | |||
HELLO WORLD | |||
<span style="color:red;">[ Main main(String[])] FINER: (Main.java:12) RETURN</span> | |||
'''$''' | |||
For demonstration, we now set the amount of logging to the highest possible level. There are several ways to configure | |||
the injection of logging code: We can pass a 'loggification rule' to the LOGGIFER like '-rule ALL=FINE', or through a '@Loggify' | |||
annotation to any class or method declaration: | |||
; | import de.unkrig.loggifier.runtime.annotation.Loggify; | ||
@Loggify("ALL=FINE") | |||
public class Main { | |||
// ... | |||
Then compile, loggify and run again: | |||
: | |||
; | '''$ javac Main.java -cp de.unkrig.loggifier-runtime.jar''' | ||
: | '''$ java -cp de.unkrig.loggifier.jar de.unkrig.loggifier.Main Main.class''' | ||
'''$ java -Djava.util.logging.config.file=my_logging.properties -cp de.unkrig.loggifier-runtime.jar\;. Main''' | |||
<span style="color:red;">[ Main <clinit>()] FINE: (Main.java:1) CLINIT Main</span> | |||
<span style="color:red;">[ Main <clinit>()] FINE: (Main.java:9) ENTRY args=()</span> | |||
<span style="color:red;">[ Main <clinit>()] FINE: (Main.java:9) CONST "Main.USER"</span> | |||
<span style="color:red;">[ Main <clinit>()] FINE: (Main.java:9) INVOKE Logger.getLogger(String): args=("Main.USER")</span> | |||
<span style="color:red;">[ Main <clinit>()] FINE: (Main.java:9) RESULT Logger.getLogger(String) => java.util.logging.Logger@53c60f74</span> | |||
<span style="color:red;">[ Main <clinit>()] FINE: (Main.java:9) PUT java.util.logging.Logger@53c60f74 => Main.LOGGER</span> | |||
<span style="color:red;">[ Main <clinit>()] FINE: (Main.java:9) RETURN</span> | |||
<span style="color:red;">[ Main main(String[])] FINE: (Main.java:12) ENTRY args=(args=String[0])</span> | |||
<span style="color:red;">[ Main main(String[])] FINE: (Main.java:12) GET System.out => java.io.PrintStream@7020b3a3</span> | |||
<span style="color:red;">[ Main main(String[])] FINE: (Main.java:12) CONST "HELLO WORLD"</span> | |||
<span style="color:red;">[ Main main(String[])] FINE: (Main.java:12) INVOKE PrintStream.println(String): target=java.io.PrintStream@7020b3a3, args=("HELLO WORLD")</span> | |||
HELLO WORLD | |||
<span style="color:red;">[ Main main(String[])] FINE: (Main.java:12) RESULT PrintStream.println(String)</span> | |||
<span style="color:red;">[ Main main(String[])] FINE: (Main.java:14) GET Main.LOGGER => java.util.logging.Logger@53c60f74</span> | |||
<span style="color:red;">[ Main main(String[])] FINE: (Main.java:14) CONST "About to terminate"</span> | |||
<span style="color:red;">[ Main main(String[])] FINE: (Main.java:14) INVOKE Logger.fine(String): target=java.util.logging.Logger@53c60f74, args=("About to terminate")</span> | |||
<span style="color:red;">[ Main main] FINE: About to terminate</span> | |||
<span style="color:red;">[ Main main(String[])] FINE: (Main.java:14) RESULT Logger.fine(String)</span> | |||
<span style="color:red;">[ Main main(String[])] FINE: (Main.java:15) RETURN</span> | |||
'''$''' | |||
(Notice that JAVAC now needs "de.unkrig.loggifier-runtime.jar" on the class path, because "@de.unkrig.loggifier.runtime.annotation.Loggify" lives there.) | |||
Now you can watch how the <code>System.out</code> field is read and the string constant <code>"HELLO WORLD"</code> is used - if you're interested. | |||
== Usage == | |||
=== Command line tool === | |||
'''$ java -cp de.unkrig.loggifier.jar de.unkrig.loggifier.Main -help''' | |||
: | Implants logging code into Java class files 'in-place', also in ZIP format | ||
files (zip, jar, war, ear, ...) files and nested ZIP format files. | |||
Usage: | |||
java de.unkrig.loggifier.Main [ <option> ] ... <dir-or-file> | |||
java de.unkrig.loggifier.Main [ <option> ] ... <dir-or-file> <dir-or-file> | |||
java de.unkrig.loggifier.Main [ <option> ] ... <dir-or-file> ... <dir> | |||
Valid options: | |||
-keep Keep copies of original files | |||
-selector <pattern> | |||
Loggify only classes matching the <pattern> | |||
-rule <rule> Add the given rule | |||
The rule format is as follows | |||
<action>[,<action>]...=<level>[:<expression>] | |||
<action> is one of [ALOAD, ARITH, ASTORE, CAST, CATCH, CLINIT, CONST, CONVERT, ENTRY, GET, INVOKE, INSTANCEOF, | |||
LENGTH, LOAD, NEW, PUT, RESULT, RETURN, STORE, SWITCH, THROW] | |||
<level> is one of [ OFF SEVERE WARNING INFO CONFIG FINE FINER FINEST ] | |||
<expression> is like '(<eq> || <eq>) && !<eq>', where | |||
<eq> is '<var> == <glob>', where | |||
<var> is one of [ class source line ] (for action 'STORE' also 'name'). | |||
<glob> is a 'glob pattern' in single quotes like '*main*'. | |||
The exit status is 1 iff errors eccurred during loggification. | |||
=== ECLIPSE Plugin === | |||
When the plug-in is installed (see below), you will find a new page in the 'Project Properties...' dialog: | |||
: | |||
[[File:Loggifer_project_properties_page.png]] | |||
: | |||
Here you can enable and configure loggification for the project. | |||
=== ANT task === | |||
LOGGIFIER defines a new task. | |||
=== | ==== Attributes ==== | ||
;selector :Which class files to instrument, e.g. "~**Test*.class". Default is "all files". | |||
;out :Where to write the output file or directory. Default is to perform an "in-place" loggification | |||
;keepOriginals :Keep copies of the original files (e.g. '.MyClass.class.orig' and '.MyJar.jar.orig'). | |||
=== | ==== Subelements ==== | ||
;rule :A loggification rule, e.g. 'STORE=FINE' | |||
;Resource Collection (<fileset> etc.) :The files to loggify (.class, .jar, .war, .ear, ...) | |||
==== Example ==== | |||
<project> | |||
<taskdef name="loggifier" classname="de.unkrig.loggifier.AntTask" classpath="lib/de.unkrig.loggifier.jar" /> | |||
<target name="default"> | |||
<loggifier> | |||
<rule>ALL=FINE</rule> | |||
<fileset file="bin/Main.class" /> | |||
</loggifier> | |||
</target> | |||
</project> | |||
== Download == | == Download == |