Class to convert Processbuilder to Linux Shell commands.

ProcessBuilderSerializer.java

import java.io.File;
import java.lang.ProcessBuilder.Redirect.Type;
import java.util.Arrays;

import org.apache.log4j.BasicConfigurator;
import org.apache.log4j.Level;
import org.apache.log4j.Logger;

/** This Class Provides a Way to Serialize and deserialize Simple Processbuilder Commands. For this it will use the Bash Syntax.
 * 
 * @author Aron Schaub */
public class ProcessBuilderSerializer {
    private static Logger Log = Logger.getLogger(ProcessBuilderSerializer.class);

    /** just for Example Purpose.
     * 
     * @param args will not be used */
    public static void main(String[] args) {
        BasicConfigurator.configure();
        Logger.getRootLogger().setLevel(Level.ALL);
        String t1 = "echo 20 > /dev/null";
        String t2 = "echo < /etc/myFile";
        String t3 = "echo 20 2> /dev/null";
        String t4 = "echo 20";
        String t5 = "echo 20 > /dev/null < /etc/myFile";
        String t6 = "echo 20 < /etc/myFile > /dev/null";
        String t7 = "echo 20 2>&1 > /dev/null";

        Log.debug("--------------------------------------------");
        Log.debug(t1);
        Log.debug(ProcessBuilderToBash(BashToProcessBuilder(t1)));
        Log.debug("--------------------------------------------");
        Log.debug(t2);
        Log.debug(ProcessBuilderToBash(BashToProcessBuilder(t2)));
        Log.debug("--------------------------------------------");
        Log.debug(t3);
        Log.debug(ProcessBuilderToBash(BashToProcessBuilder(t3)));
        Log.debug("--------------------------------------------");
        Log.debug(t4);
        Log.debug(ProcessBuilderToBash(BashToProcessBuilder(t4)));
        Log.debug("--------------------------------------------");
        Log.debug(t5);
        Log.debug(ProcessBuilderToBash(BashToProcessBuilder(t5)));
        Log.debug("--------------------------------------------");
        Log.debug(t6);
        Log.debug(ProcessBuilderToBash(BashToProcessBuilder(t6)));
        Log.debug("--------------------------------------------");
        Log.debug(t7);
        Log.debug(ProcessBuilderToBash(BashToProcessBuilder(t7)));
    }

    /** creates a String out of the given ProcessBuilder Object@return
     * 
     * @param pb Fully functional Processbuilder Object
     * @return a String without \n or other special Characters. */
    public static String ProcessBuilderToBash(ProcessBuilder pb) {
        StringBuilder sb = new StringBuilder();
        for (String string : pb.command()) {
            sb.append(string).append(" ");
        }
        if (pb.redirectErrorStream()) {
            sb.append("2>&1 ");
        }
        if (pb.redirectInput().file() != null) {
            sb.append("< ").append(pb.redirectInput().file()).append(" ");
        }
        if (pb.redirectOutput().file() != null) {
            if (pb.redirectOutput().type().equals(Type.WRITE)) {
                sb.append("> ");
            } else if (pb.redirectOutput().type().equals(Type.APPEND)) {
                sb.append(">> ");
            }
            sb.append(pb.redirectOutput().file()).append(" ");
        }
        if (pb.redirectError().file() != null) {
            sb.append("2> ").append(pb.redirectError().file());
        }
        String ret = sb.toString();
        if (ret.endsWith(" ")) {
            ret = ret.substring(0, ret.lastIndexOf(" "));
        }
        return ret;
    }

    /** creates A Processbuilder Object out of a String
     * 
     * @param s String representing a simple Bash command.
     * @return Processbuilder object, that can be run. */
    public static ProcessBuilder BashToProcessBuilder(String s) {
        String splitted[] = s.split("(?=2>&1|<|2>|>>| >)");
        ProcessBuilder pb = new ProcessBuilder();
        for (String string : splitted) {
            Log.debug("\t" + string);
            if (string.contains("2>&1")) {
                pb.redirectErrorStream(true);
            } else if (string.contains("< ")) {
                pb.redirectInput(new File(string.replace("< ", "")));
            } else if (string.contains(">> ")) {
                pb.redirectOutput(new File(string.replace(">> ", "")));
            } else if (string.contains("2> ")) {
                pb.redirectError(new File(string.replace("2> ", "")));
            } else if (string.contains(" > ")) {
                pb.redirectOutput(new File(string.replace(" > ", "")));
            } else {
                pb.command().addAll(Arrays.asList(string.split("\\s")));
            }
        }
        return pb;
    }
}