// Jps.java // Andrew Davison, ad@coe.psu.ac.th, June 2023 /* A simplified version of ps Man page: https://man7.org/linux/man-pages/man1/ps.1.html Usage: Jps [-ahlV] [-c=] [-r=] [-p=PID[,PID...]]... A simple Java version of ps. -a, --all print info about all processes -c, --command= list only command name processes -h, --help Show this help message and exit. -l, --label print field labels -p, --pids=PID[,PID...] selects the processes in pidlist -r, --range= selects pids based on min-max range -V, --version Print version information and exit. Picocli features: * named options and positional parameters * POSIX-style grouped short options * automatic help and version options * exit codes * Split Regex * option labels * arity * Value Validation * use of ParameterException Usage examples: > compile Jps.java > run Jps > run Jps -l > run Jps -al > run Jps -r=10000-15000 > run Jps -p=11224,11900,11904 > run Jps -c=note */ import java.io.*; import java.util.*; import java.time.*; import java.text.*; import java.util.concurrent.*; import picocli.CommandLine; import picocli.CommandLine.*; import picocli.CommandLine.Model.CommandSpec; @Command(name = "Jps", mixinStandardHelpOptions = true, version = "Jps 1.0", description = "A simple Java version of ps.") public class Jps implements Callable { private static final SimpleDateFormat sdf = new SimpleDateFormat("dd-MM-yyyy;HH:mm:ss"); @CommandLine.Option(names = {"-a", "--all"}, description = "print info on all processes") private boolean showAll = false; @CommandLine.Option(names = {"-l", "--label"}, description = "print field labels") private boolean showLabels = false; @Option(names = { "-c", "--command" }, description = "list only processes for command name") private String cmdName = null; @Option(names = { "-p", "--pids" }, split=",", paramLabel = "PID", description = "list the processes in pidlist") private long[] pidlist; private long[] pidRange; @Spec CommandSpec spec; @Option(names = { "-r", "--range"}, paramLabel = "", description = "list processes in pid range") public void setRange(String vals) // validation // convert string to an array of two pids: [ min, max ] { String[] valsArr = vals.split("-"); if (valsArr.length != 2) throw new ParameterException( spec.commandLine(), String.format( "Invalid range format %s", vals) ); else { long[] vs = new long[2]; vs[0] = getLong(valsArr[0]); vs[1] = getLong(valsArr[1]); if (vs[0] > vs[1]) throw new ParameterException( spec.commandLine(), String.format( "Wrong range order %s", vals) ); else pidRange = vs; } } // end of setRange() private String today; private String usrName; public Integer call() { if (showLabels) { System.out.printf("%7s %15s %10s %2s %4s %7s %22s %5s\n", "PID", "Command", "User", "Al", "Kids", "PPID", center("Start Time", 20), "CPU"); System.out.print(" " + "-".repeat(80) + "\n"); } usrName = System.getProperty("user.name"); if (cmdName != null) cmdName = cmdName.toLowerCase(); if (pidlist != null) Arrays.sort(pidlist); // so can use binary search SimpleDateFormat dayDF = new SimpleDateFormat("dd-MM-yyyy"); today = dayDF.format(new Date()); // only store the day part ProcessHandle.allProcesses().forEach( ph -> examineProc(ph)); return 0; } // end of call() public static long getLong(String s) { long num = 0; try { num = Long.parseLong(s); } catch (NumberFormatException ex){ System.out.println("Incorrect format for int " + s); } return num; } // end of getLong() private void examineProc(ProcessHandle ph) // print the details for the ph process { ProcessHandle.Info pInfo = ph.info(); if (showAll) System.out.println( procDetails(ph, pInfo)); else if (pidRange != null) { if ((ph.pid() >= pidRange[0]) && (ph.pid() <= pidRange[1])) System.out.println( procDetails(ph, pInfo)); } else if (pidlist != null) { if (Arrays.binarySearch(pidlist, ph.pid()) >= 0) // found System.out.println( procDetails(ph, pInfo)); } else if (cmdName != null) { String cmd = optString( pInfo.command()).toLowerCase(); if (cmd.contains(cmdName)) // allows for a partial match System.out.println( procDetails(ph, pInfo)); } else { // only show user's processes String pName = optString( pInfo.user()); if (pName.contains(usrName)) System.out.println( procDetails(ph, pInfo)); } } // end of examineProc() private String procDetails(ProcessHandle ph, ProcessHandle.Info pInfo) // format the process details for the ph process { long duration = pInfo.totalCpuDuration() .orElse(Duration.ZERO) .getSeconds(); return String.format("%7d %15s %10s %2s %4d %7s %22s %5d", ph.pid(), getCommand(optString( pInfo.command())), getUser( optString( pInfo.user())), ph.isAlive() ? "t" : "F", ph.children().count(), optString( ph.parent().map(ProcessHandle::pid)), center( getStartTime(pInfo), 20), duration ); } /* procDetails */ private String getStartTime(ProcessHandle.Info pInfo) // return "day;time" if the day is not today, or just "time" { Instant start = pInfo.startInstant() .orElse(Instant.now()); String startStr = sdf.format( Date.from(start)); if (startStr.contains(today)) // it is today, so strip the day startStr = startStr.substring( startStr.indexOf(";")+1); return startStr; } // end of getStartTime() private String optString(Optional optional) // return the data or "-" { return optional.map( Object::toString ).orElse("-"); } private String getUser(String user) // strip away any path prefix on the user name { int index = user.lastIndexOf(File.separator); return (index == -1) ? user : user.substring(index + 1); } private String getCommand(String cmdName) /* strip away any path prefix on the command name, and also ".exe" at the end of the command, and truncate the string to <= 15 chars */ { int index = cmdName.lastIndexOf(File.separator); if (index != -1) cmdName = cmdName.substring(index + 1); index = cmdName.lastIndexOf(".exe"); if (index != -1) cmdName = cmdName.substring(0, index); if (cmdName.length() > 15) return cmdName.substring(0, 12) + "..."; else return cmdName; } // end of getCommand() private String center(String s, int len) // center the string in len spaces { StringBuilder sb = new StringBuilder(len); sb.setLength((len - s.length())/2); sb.append(s); sb.setLength(len); return sb.toString().replace('\0', ' '); } // end of center() // --------------------------------------------- public static void main(String[] args) { int exitCode = new CommandLine(new Jps()).execute(args); System.exit(exitCode); } } // end of Jps class