org.sonatype.plugins.munge

Class Munge

java.lang.Object

org.sonatype.plugins.munge.Munge

public class Munge
extends Object

Munge: a purposely-simple Java preprocessor. It only supports conditional inclusion of source based on defined strings of the form "if[tag]", "if_not[tag]", "else[tag], and "end[tag]". Unlike traditional preprocessors, comments and formatting are all preserved for the included lines. This is on purpose, as the output of Munge will be distributed as human-readable source code.

To avoid creating a separate Java dialect, the conditional tags are contained in Java comments. This allows one build to compile the source files without pre-processing, to facilitate faster incremental development. Other builds from the same source have their code contained within that comment. The format of the tags is a little verbose, so that the tags won't accidentally be used by other comment readers such as javadoc. Munge tags must be in C-style comments; C++-style comments may be used to comment code within a comment.

To demonstrate this, our sample source has 1.1 and 1.2-specific code, with 1.1 as the default build:

     public void setSystemProperty(String key, String value) {
         /*if[JDK1.1]*/
         Properties props = System.getProperties();
         props.setProperty(key, value);
         System.setProperties(props);
         /*end[JDK1.1]*/
 

         /*if[JDK1.2]
         // Use the new System method.
         System.setProperty(key, value);
           end[JDK1.2]*/
     }
 

When the above code is directly compiled, the code bracketed by the JDK1.1 tags will be used. If the file is run through Munge with the JDK1.2 tag defined, the second code block will used instead. This code can also be written as:

     public void setSystemProperty(String key, String value) {
         /*if[JDK1.2]
         // Use the new System method.
         System.setProperty(key, value);
           else[JDK1.2]*/
 

         Properties props = System.getProperties();
         props.setProperty(key, value);
         System.setProperties(props);
         /*end[JDK1.2]*/
     }
 

Munge also performs text substitution; the Swing build uses this to convert its package references from javax.swing to java.awt.swing, for example. This substitution is has no knowledge of Java syntax, so only use it to convert strings which are unambiguous. Substitutions are made in the same order as the arguments are specified, so the first substitution is made over the whole file before the second one, and so on.

Munge's command line takes one of the following forms:

    java Munge [-D<symbol> ...] [-s <old>=<new> ...] [<in file>] [<out file>]
    java Munge [-D<symbol> ...] [-s <old>=<new> ...] <file> ... <directory>
 

In the first form, if no output file is given, System.out is used. If neither input nor output file are given, System.in and System.out are used. Munge can also take an @<cmdfile> argument. If one is specified then the given file is read for additional command line arguments.

Like any preprocessor, developers must be careful not to abuse its capabilities so that their code becomes unreadable. Please use it as little as possible.

Author:

jessewilson@google.com (Jesse Wilson)

Constructor Summary

Constructors

Constructor and Description
Munge(String inName, String outName)

Method Summary

Modifier and Type	Method and Description
void	close()
void	error(String text)
boolean	hasErrors()
static void	main(String[] args) Munge's main entry point.
void	printErrorCount()
void	process()
static void	usage() Report how this utility is used and exit.
static void	usage(String msg)

Methods inherited from class java.lang.Object

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

Constructor Detail

Munge

public Munge(String inName,
             String outName)

Method Detail

error

public void error(String text)

printErrorCount

public void printErrorCount()

hasErrors

public boolean hasErrors()

close

public void close()
           throws IOException

Throws:

IOException

process

public void process()
             throws IOException

Throws:

IOException

usage

public static void usage()

Report how this utility is used and exit.

usage

public static void usage(String msg)

main

public static void main(String[] args)

Munge's main entry point.