org.spearce.jgit.pgm/src/org/spearce/jgit/pgm/opt/SubcommandHandler.java

   1 /*
   2  * Copyright (C) 2008, Shawn O. Pearce <spearce@spearce.org>
   3  *
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or
   7  * without modification, are permitted provided that the following
   8  * conditions are met:
   9  *
  10  * - Redistributions of source code must retain the above copyright
  11  *   notice, this list of conditions and the following disclaimer.
  12  *
  13  * - Redistributions in binary form must reproduce the above
  14  *   copyright notice, this list of conditions and the following
  15  *   disclaimer in the documentation and/or other materials provided
  16  *   with the distribution.
  17  *
  18  * - Neither the name of the Git Development Community nor the
  19  *   names of its contributors may be used to endorse or promote
  20  *   products derived from this software without specific prior
  21  *   written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
  24  * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
  25  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  26  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
  28  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  29  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  30  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  31  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  32  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  33  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  34  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  35  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36  */
  37
  38 package org.spearce.jgit.pgm.opt;
  39
  40 import java.lang.reflect.Constructor;
  41 import java.lang.reflect.InvocationTargetException;
  42 import java.text.MessageFormat;
  43
  44 import org.kohsuke.args4j.CmdLineException;
  45 import org.kohsuke.args4j.CmdLineParser;
  46 import org.kohsuke.args4j.OptionDef;
  47 import org.kohsuke.args4j.spi.OptionHandler;
  48 import org.kohsuke.args4j.spi.Parameters;
  49 import org.kohsuke.args4j.spi.Setter;
  50 import org.spearce.jgit.pgm.Main;
  51 import org.spearce.jgit.pgm.TextBuiltin;
  52
  53 /**
  54  * Custom Argument handler for jgit command selection.
  55  * <p>
  56  * Translates a single argument string to a {@link TextBuiltin} instance which
  57  * we can execute at runtime with the remaining arguments of the parser.
  58  */
  59 public class SubcommandHandler extends OptionHandler<TextBuiltin> {
  60         private static String mypackage() {
  61                 final String p = Main.class.getName();
  62                 final int dot = p.lastIndexOf('.');
  63                 return p.substring(0, dot);
  64         }
  65
  66         /**
  67          * Create a new handler for the command name.
  68          * <p>
  69          * This constructor is used only by args4j.
  70          *
  71          * @param parser
  72          * @param option
  73          * @param setter
  74          */
  75         public SubcommandHandler(final CmdLineParser parser,
  76                         final OptionDef option, final Setter<? super TextBuiltin> setter) {
  77                 super(parser, option, setter);
  78         }
  79
  80         @Override
  81         public int parseArguments(final Parameters params) throws CmdLineException {
  82                 final String name = params.getParameter(0);
  83                 final StringBuilder s = new StringBuilder();
  84                 s.append(mypackage());
  85                 s.append('.');
  86                 boolean upnext = true;
  87                 for (int i = 0; i < name.length(); i++) {
  88                         final char c = name.charAt(i);
  89                         if (c == '-') {
  90                                 upnext = true;
  91                                 continue;
  92                         }
  93                         if (upnext)
  94                                 s.append(Character.toUpperCase(c));
  95                         else
  96                                 s.append(c);
  97                         upnext = false;
  98                 }
  99
 100                 final Class<?> clazz;
 101                 try {
 102                         clazz = Class.forName(s.toString());
 103                 } catch (ClassNotFoundException e) {
 104                         throw new CmdLineException(MessageFormat.format(
 105                                         "{0} is not a jgit command", name));
 106                 }
 107
 108                 if (!TextBuiltin.class.isAssignableFrom(clazz))
 109                         throw new CmdLineException(MessageFormat.format(
 110                                         "{0} is not a jgit command", name));
 111
 112                 final Constructor<?> cons;
 113                 try {
 114                         cons = clazz.getDeclaredConstructor();
 115                 } catch (SecurityException e) {
 116                         throw new CmdLineException("Cannot create " + name, e);
 117                 } catch (NoSuchMethodException e) {
 118                         throw new CmdLineException("Cannot create " + name, e);
 119                 }
 120                 cons.setAccessible(true);
 121
 122                 final TextBuiltin cmd;
 123                 try {
 124                         cmd = (TextBuiltin) cons.newInstance();
 125                 } catch (InstantiationException e) {
 126                         throw new CmdLineException("Cannot create " + name, e);
 127                 } catch (IllegalAccessException e) {
 128                         throw new CmdLineException("Cannot create " + name, e);
 129                 } catch (InvocationTargetException e) {
 130                         throw new CmdLineException("Cannot create " + name, e);
 131                 }
 132
 133                 cmd.setCommandName(name);
 134                 setter.addValue(cmd);
 135
 136                 // Force option parsing to stop. Everything after us should
 137                 // be arguments known only to this command and must not be
 138                 // recognized by the current parser.
 139                 //
 140                 owner.stopOptionParsing();
 141
 142                 return 1;
 143         }
 144
 145         @Override
 146         public String getDefaultMetaVariable() {
 147                 return "command";
 148         }
 149 }