Generates java source from a jar file (e.g. for use in javadoc)

jar2java

#!/bin/sh
#
# Transforms a jar file into source and outputs source files to 'src'.
# Example:
#
#   jar2java foo.jar  ; --> source to 'src'
#
# After you can run javadoc on these files, e.g.
#
#   javadoc -classpath foo.jar -d api `find src -name "*.java"`
#

process_class()
{
    src=$1; shift
    jar=$1; shift
    cls=$1; shift

    file=$(echo $cls | sed 's/\./\//g')
    file="$src/$file.java"
    if [[ -f $file ]]; then
	echo "Skipping $file"
	return
    fi

    # Remove fully-qualified name
    simple_cls=$(echo $cls | sed 's/.*\.//g')
    text=$(javap -classpath "$jar" $cls | sed -e "s/$cls/$simple_cls/g")

    # Add variable names, this is pretty gross
    while [[ $text =~ ',' ]]; do
	var="v_$RANDOM"
	text=$(echo $text | sed "s/,/ $var# /")
    done
    text=$(echo $text | sed 's/#/,/g')

    # Add bodies to methods with no params
    text=$(echo $text | sed 's/();/() {}/g')

    # Add last parameter and bodies to methods
    while [[ $text =~ ');' ]]; do
	var="v_$RANDOM"
	text=$(echo $text | sed "s/);/ $var) {}/")
    done
    
    # Save if to the file
    mkdir -p $(dirname $file)
    echo $file
    echo $text > $file
}

process()
{
    src=$1; shift
    jar=$1; shift
    classes=$(jar tvf $jar | awk '/\.class$/ {print $NF}' | \
	sed -e 's/\//./g' -e 's/.class$//g')
    for cls in $classes; do
	process_class $src $jar $cls
    done
}

src="src"
mkdir -p $src
echo "Writing to $src"
for f in "$@"; do
    process $src $f
done