org.argeo.core/src/org/argeo/cli/HelpCommand.java

   1 package org.argeo.cli;
   2
   3 import java.io.PrintWriter;
   4 import java.io.StringWriter;
   5 import java.util.List;
   6 import java.util.function.Function;
   7
   8 import org.apache.commons.cli.HelpFormatter;
   9 import org.apache.commons.cli.Options;
  10
  11 /** A special command that can describe {@link DescribedCommand}. */
  12 public class HelpCommand implements DescribedCommand<String> {
  13         private CommandsCli commandsCli;
  14         private CommandsCli parentCommandsCli;
  15
  16         // Help formatting
  17         private static int helpWidth = 80;
  18         private static int helpLeftPad = 4;
  19         private static int helpDescPad = 20;
  20
  21         public HelpCommand(CommandsCli parentCommandsCli, CommandsCli commandsCli) {
  22                 super();
  23                 this.parentCommandsCli = parentCommandsCli;
  24                 this.commandsCli = commandsCli;
  25         }
  26
  27         @Override
  28         public String apply(List<String> args) {
  29                 StringWriter out = new StringWriter();
  30
  31                 if (args.size() == 0) {// overview
  32                         printHelp(commandsCli, out);
  33                 } else {
  34                         String cmd = args.get(0);
  35                         Function<List<String>, ?> function = commandsCli.getCommand(cmd);
  36                         if (function == null)
  37                                 return "Command " + cmd + " not found.";
  38                         Options options;
  39                         String examples;
  40                         DescribedCommand<?> command = null;
  41                         if (function instanceof DescribedCommand) {
  42                                 command = (DescribedCommand<?>) function;
  43                                 options = command.getOptions();
  44                                 examples = command.getExamples();
  45                         } else {
  46                                 options = new Options();
  47                                 examples = null;
  48                         }
  49                         String description = getShortDescription(function);
  50                         String commandCall = getCommandUsage(cmd, command);
  51                         HelpFormatter formatter = new HelpFormatter();
  52                         formatter.printHelp(new PrintWriter(out), helpWidth, commandCall, description, options, helpLeftPad,
  53                                         helpDescPad, examples, false);
  54                 }
  55                 return out.toString();
  56         }
  57
  58         private static String getShortDescription(Function<List<String>, ?> function) {
  59                 if (function instanceof DescribedCommand) {
  60                         return ((DescribedCommand<?>) function).getDescription();
  61                 } else {
  62                         return function.toString();
  63                 }
  64         }
  65
  66         public String getCommandUsage(String cmd, DescribedCommand<?> command) {
  67                 String commandCall = getCommandCall(commandsCli) + " " + cmd;
  68                 assert command != null;
  69                 if (command != null && command.getUsage() != null) {
  70                         commandCall = commandCall + " " + command.getUsage();
  71                 }
  72                 return commandCall;
  73         }
  74
  75         @Override
  76         public String getDescription() {
  77                 return "Shows this help or describes a command";
  78         }
  79
  80         @Override
  81         public String getUsage() {
  82                 return "[command]";
  83         }
  84
  85         public CommandsCli getParentCommandsCli() {
  86                 return parentCommandsCli;
  87         }
  88
  89         protected String getCommandCall(CommandsCli commandsCli) {
  90                 HelpCommand hc = commandsCli.getHelpCommand();
  91                 if (hc.getParentCommandsCli() != null) {
  92                         return getCommandCall(hc.getParentCommandsCli()) + " " + commandsCli.getCommandName();
  93                 } else {
  94                         return commandsCli.getCommandName();
  95                 }
  96         }
  97
  98         public static void printHelp(DescribedCommand<?> command, StringWriter out) {
  99                 String usage = "java " + command.getClass().getName()
 100                                 + (command.getUsage() != null ? " " + command.getUsage() : "");
 101                 HelpFormatter formatter = new HelpFormatter();
 102                 formatter.printHelp(new PrintWriter(out), helpWidth, usage, command.getDescription(), command.getOptions(),
 103                                 helpLeftPad, helpDescPad, command.getExamples(), false);
 104
 105         }
 106
 107         public static void printHelp(CommandsCli commandsCli, String commandName, StringWriter out) {
 108                 DescribedCommand<?> command = (DescribedCommand<?>) commandsCli.getCommand(commandName);
 109                 String usage = commandsCli.getHelpCommand().getCommandUsage(commandName, command);
 110                 HelpFormatter formatter = new HelpFormatter();
 111                 formatter.printHelp(new PrintWriter(out), helpWidth, usage, command.getDescription(), command.getOptions(),
 112                                 helpLeftPad, helpDescPad, command.getExamples(), false);
 113
 114         }
 115
 116         public static void printHelp(CommandsCli commandsCli, StringWriter out) {
 117                 out.append(commandsCli.getDescription()).append('\n');
 118                 String leftPad = spaces(helpLeftPad);
 119                 for (String cmd : commandsCli.getSubCommands()) {
 120                         Function<List<String>, ?> function = commandsCli.getCommand(cmd);
 121                         assert function != null;
 122                         out.append(leftPad);
 123                         out.append(cmd);
 124                         // TODO deal with long commands
 125                         out.append(spaces(helpDescPad - cmd.length()));
 126                         out.append(getShortDescription(function));
 127                         out.append('\n');
 128                 }
 129         }
 130
 131         private static String spaces(int count) {
 132                 // Java 11
 133                 // return " ".repeat(count);
 134                 if (count <= 0)
 135                         return "";
 136                 else {
 137                         StringBuilder sb = new StringBuilder(count);
 138                         for (int i = 0; i < count; i++)
 139                                 sb.append(' ');
 140                         return sb.toString();
 141                 }
 142         }
 143 }