Added CommandRegistry interface, fixes #480

builtins/src/main/java/org/jline/builtins/Builtins.java

@@ -24,19 +24,17 @@
 import java.util.function.Supplier;
 import java.util.stream.Collectors;
 
-import org.jline.builtins.Commands;
 import org.jline.builtins.Completers.FilesCompleter;
 import org.jline.builtins.Completers.OptionCompleter;
 import org.jline.builtins.Completers.SystemCompleter;
-import org.jline.builtins.TTop;
 import org.jline.builtins.Options.HelpException;
 import org.jline.builtins.Widgets.ArgDesc;
 import org.jline.builtins.Widgets.CmdDesc;
 import org.jline.reader.Completer;
 import org.jline.reader.ConfigurationPath;
 import org.jline.reader.LineReader;
-import org.jline.reader.Widget;
 import org.jline.reader.LineReader.Option;
+import org.jline.reader.Widget;
 import org.jline.reader.impl.completer.ArgumentCompleter;
 import org.jline.reader.impl.completer.NullCompleter;
 import org.jline.reader.impl.completer.StringsCompleter;
@@ -48,7 +46,7 @@
  *
  * @author <a href="mailto:matti.rintanikkola@gmail.com">Matti Rinta-Nikkola</a>
  */
-public class Builtins {
+public class Builtins implements CommandRegistry {
     public enum Command {NANO
                        , LESS
                        , HISTORY
@@ -65,6 +63,7 @@ public enum Command {NANO
     private Map<String,Command> nameCommand = new HashMap<>();
     private Map<String,String> aliasCommand = new HashMap<>();
     private final Map<Command,CommandMethods> commandExecute = new HashMap<>();
+    private Map<Command,List<String>> commandInfo = new HashMap<>();
     private LineReader reader;
     private Exception exception;
 
@@ -105,6 +104,21 @@ public Builtins(Set<Command> commands, Supplier<Path> workDir, ConfigurationPath
         commandExecute.put(Command.TTOP, new CommandMethods(this::ttop, this::ttopCompleter));
     }
 
+    public Set<String> commandNames() {
+        return nameCommand.keySet();
+    }
+
+    public Map<String, String> commandAliases() {
+        return aliasCommand;
+    }
+
+    public List<String> commandInfo(String command) {
+        if (!commandInfo.containsKey(command(command))) {
+            commandOptions(command);
+        }
+        return commandInfo.get(command(command));
+    }
+
     private void doNameCommand() {
         nameCommand = commandName.entrySet()
                 .stream()
@@ -237,14 +251,22 @@ private Map<String,String> commandOptions(String command) {
         try {
             execute(command, args);
         } catch (HelpException e) {
+            List<String> info = new ArrayList<>();
             String[] msg = e.getMessage().replaceAll("\r\n", "\n").replaceAll("\r", "\n").split("\n");
             boolean start = false;
+            boolean first = true;
             for (String s: msg) {
                 if (!start) {
                     if (s.trim().startsWith("Usage: ")) {
                         s = s.split("Usage:")[1];
                         start = true;
                     } else {
+                        if (first && s.contains(" - ")) {
+                            info.add(s.substring(s.indexOf(" - ") + 3).trim());
+                        } else {
+                            info.add(s.trim());
+                        }
+                        first = false;
                         continue;
                     }
                 }
@@ -261,6 +283,7 @@ private Map<String,String> commandOptions(String command) {
                     }
                 }
             }
+            commandInfo.put(command(command), info);
         } catch (Exception e) {
 
         }

builtins/src/main/java/org/jline/builtins/CommandRegistry.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright (c) 2002-2019, the original author or authors.
+ *
+ * This software is distributable under the BSD license. See the terms of the
+ * BSD license in the documentation provided with this software.
+ *
+ * https://opensource.org/licenses/BSD-3-Clause
+ */
+package org.jline.builtins;
+
+import org.jline.builtins.Completers;
+import org.jline.builtins.Widgets;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+public interface CommandRegistry {
+
+    /**
+     * Returns the command names known by this registry.
+     * @return the set of known command names, excluding aliases
+     */
+    Set<String> commandNames();
+
+    /**
+     * Returns a map of alias-to-command names known by this registry.
+     * @return a map with alias keys and command name values
+     */
+    Map<String, String> commandAliases();
+
+    /**
+     * Returns a short info about command known by this registry.
+     * @return a short info about command
+     */
+    List<String> commandInfo(String command);
+
+    /**
+     * Returns whether a command with the specified name is known to this registry.
+     * @param command the command name to test
+     * @return true if the specified command is registered
+     */
+    boolean hasCommand(String command);
+
+    /**
+     * Returns a {@code SystemCompleter} that can provide detailed completion
+     * information for all registered commands.
+     * 
+     * @return a SystemCompleter that can provide command completion for all registered commands
+     */
+    Completers.SystemCompleter compileCompleters();
+
+    /**
+     * Returns a command description for use in the JLine Widgets framework.
+     * @param command name of the command whose description to return 
+     * @return command description for JLine TailTipWidgets to be displayed
+     *         in the terminal status bar.
+     */
+    Widgets.CmdDesc commandDescription(String command);
+}