1 |
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2 | package de.ugoe.cs.util.console;
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3 |
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4 | import java.io.File;
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5 | import java.io.FileInputStream;
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6 | import java.io.FilenameFilter;
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7 | import java.io.IOException;
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8 | import java.net.URL;
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9 | import java.security.InvalidParameterException;
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10 | import java.util.ArrayList;
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11 | import java.util.Arrays;
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12 | import java.util.Enumeration;
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13 | import java.util.List;
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14 | import java.util.jar.JarEntry;
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15 | import java.util.jar.JarInputStream;
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16 | import java.util.logging.Level;
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17 |
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18 | /**
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19 | * <p>
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20 | * Executes commands. The commands have to implement the {@link Command} interface and be in
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21 | * packages registered using addCommandPackage(). Additionally, default commands are implemented in
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22 | * the de.ugoe.cs.util.console.defaultcommands package.
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23 | * </p>
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24 | * <p>
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25 | * This class is implemented as a <i>Singleton</i>.
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26 | * </p>
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27 | *
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28 | * @author Steffen Herbold
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29 | * @version 1.0
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30 | */
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31 | public class CommandExecuter {
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32 |
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33 | /**
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34 | * <p>
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35 | * Handle of the CommandExecuter instance.
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36 | * </p>
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37 | */
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38 | private final static CommandExecuter theInstance = new CommandExecuter();
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39 |
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40 | /**
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41 | * <p>
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42 | * Prefix of all command classes.
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43 | * </p>
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44 | */
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45 | private static final String cmdPrefix = "CMD";
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46 |
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47 | /**
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48 | * <p>
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49 | * Name of the package for default commands.
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50 | * </p>
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51 | */
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52 | private static final String defaultPackage = "de.ugoe.cs.util.console.defaultcommands";
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53 |
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54 | /**
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55 | * <p>
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56 | * List of packages in which commands may be defined. The exec methods trys to load command from
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57 | * these packages in the order they have been added.
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58 | * </p>
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59 | * <p>
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60 | * The de.ugoe.cs.util.console.defaultcommands package has always lowest priority, unless it is
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61 | * specifically added.
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62 | * </p>
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63 | */
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64 | private List<String> commandPackageList;
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65 |
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66 | /**
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67 | * <p>
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68 | * Returns the instance of CommandExecuter. If no instances exists yet, a new one is created.
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69 | * </p>
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70 | *
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71 | * @return the instance of CommandExecuter
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72 | */
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73 | public static synchronized CommandExecuter getInstance() {
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74 | return theInstance;
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75 | }
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76 |
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77 | /**
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78 | * <p>
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79 | * Creates a new CommandExecuter. Private to prevent multiple instances (Singleton).
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80 | * </p>
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81 | */
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82 | private CommandExecuter() {
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83 | commandPackageList = new ArrayList<String>();
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84 | }
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85 |
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86 | /**
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87 | * <p>
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88 | * Adds a package that will be used by {@link #exec(String)} to load command from.
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89 | * </p>
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90 | *
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91 | * @param pkg
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92 | * package where commands are located
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93 | * @throws InvalidParameterException
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94 | * thrown if the package name is null or empty string
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95 | */
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96 | public void addCommandPackage(String pkg) {
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97 | if ("".equals(pkg) || pkg == null) {
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98 | throw new InvalidParameterException("package name must not be null or empty string");
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99 | }
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100 | commandPackageList.add(pkg);
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101 | }
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102 |
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103 | /**
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104 | * <p>
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105 | * Executes the command defined by string. A command has the following form (mix of EBNF and
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106 | * natural language):
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107 | * </p>
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108 | * <code>
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109 | * <command> := <commandname><whitespace>{<parameter>}<br>
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110 | * <commandname> := String without whitespaces. Has to be a valid Java class name<br>
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111 | * <parameter> := <string>|<stringarray><br>
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112 | * <string> := <stringwithoutwhitespaces>|<stringwithwhitespaces>
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113 | * <stringwithoutwhitespaces> := a string without whitespaces<br>
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114 | * <stringwithoutwhitespaces> := a string, that can have whitespaces, but must be in double quotes<br>
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115 | * <stringarray> := "["<string>{<whitespace><string>"]"
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116 | * </code>
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117 | *
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118 | * @param command
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119 | * the command as a string
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120 | */
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121 | public void exec(String command) {
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122 | Console.commandNotification(command);
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123 | Command cmd = null;
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124 | CommandParser parser = new CommandParser();
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125 | parser.parse(command);
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126 | for (int i = 0; cmd == null && i < commandPackageList.size(); i++) {
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127 | cmd = loadCMD(commandPackageList.get(i) + "." + cmdPrefix + parser.getCommandName());
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128 | }
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129 | if (cmd == null) { // check if command is available as default command
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130 | cmd = loadCMD(defaultPackage + "." + cmdPrefix + parser.getCommandName());
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131 | }
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132 | if (cmd == null) {
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133 | Console.println("Unknown command");
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134 | }
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135 | else {
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136 | try {
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137 | cmd.run(parser.getParameters());
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138 | }
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139 | catch (InvalidParameterException e) {
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140 | cmd.help();
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141 | }
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142 | }
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143 | }
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144 |
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145 | /**
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146 | * <p>
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147 | * Helper method that loads a class and tries to cast it to {@link Command}.
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148 | * </p>
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149 | *
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150 | * @param className
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151 | * qualified name of the class (including package name)
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152 | * @return if class is available and implement {@link Command} and instance of the class, null
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153 | * otherwise
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154 | */
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155 | private Command loadCMD(String className) {
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156 | Command cmd = null;
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157 | try {
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158 | Class<?> cmdClass = Class.forName(className);
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159 | cmd = (Command) cmdClass.newInstance();
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160 | }
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161 | catch (NoClassDefFoundError e) {
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162 | String[] splitResult = e.getMessage().split("CMD");
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163 | String correctName = splitResult[splitResult.length - 1].replace(")", "");
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164 | Console.println("Did you mean " + correctName + "?");
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165 | }
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166 | catch (ClassNotFoundException e) {}
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167 | catch (IllegalAccessException e) {}
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168 | catch (InstantiationException e) {}
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169 | catch (ClassCastException e) {
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170 | Console.traceln(Level.WARNING, className + "found, but does not implement Command");
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171 | }
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172 | return cmd;
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173 | }
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174 |
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175 | /**
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176 | * <p>
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177 | * reads all available commands from the registered command packages and returns a list of
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178 | * their names
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179 | * </p>
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180 | *
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181 | * @return an array containing the names of the available commands.
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182 | */
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183 | public String[] getAvailableCommands() {
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184 | List<String> commands = new ArrayList<String>();
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185 | List<String> packages = new ArrayList<String>();
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186 | packages.addAll(commandPackageList);
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187 | packages.add(defaultPackage);
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188 |
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189 | FilenameFilter filter = new FilenameFilter() {
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190 | @Override
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191 | public boolean accept(File dir, String name) {
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192 | return (name != null) && (name.startsWith(cmdPrefix)) && (name.endsWith(".class"));
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193 | }
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194 | };
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195 |
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196 | List<String> classNames = new ArrayList<String>();
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197 | for (String packageName : packages) {
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198 | String path = packageName.replace('.', '/');
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199 | try {
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200 | Enumeration<URL> resources = ClassLoader.getSystemResources(path);
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201 |
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202 | while (resources.hasMoreElements()) {
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203 | URL resource = resources.nextElement();
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204 | File packageDir = new File(resource.getFile());
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205 |
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206 | if (packageDir.isDirectory()) {
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207 | for (File classFile : packageDir.listFiles(filter)) {
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208 | String className = classFile.getName().substring
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209 | (0, classFile.getName().lastIndexOf('.'));
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210 | classNames.add(packageName + "." + className);
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211 | }
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212 | }
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213 | else {
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214 | resource.getFile().startsWith("file:");
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215 | int index = resource.getFile().lastIndexOf('!');
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216 | if ((index > 0) && (resource.getFile().startsWith("file:")) &&
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217 | (resource.getFile().endsWith("!/" + path)))
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218 | {
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219 | String jarFile = resource.getFile().substring("file:".length(), index);
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220 |
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221 | // we have to read the package content from a jar file
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222 | JarInputStream jarInputStream = null;
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223 | try {
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224 | jarInputStream = new JarInputStream(new FileInputStream(jarFile));
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225 | }
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226 | catch (Exception e) {
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227 | e.printStackTrace();
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228 | Console.traceln
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229 | (Level.WARNING, "could not read contents of jar " + jarFile);
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230 | }
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231 |
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232 | JarEntry entry = null;
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233 | do {
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234 | entry = jarInputStream.getNextJarEntry();
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235 | if ((entry != null) && (!entry.isDirectory()) &&
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236 | (entry.getName().startsWith(path)))
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237 | {
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238 | String className = entry.getName().substring
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239 | (path.length(), entry.getName().lastIndexOf('.'));
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240 | classNames.add(packageName + "." + className);
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241 | }
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242 | }
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243 | while (entry != null);
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244 | }
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245 | }
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246 | }
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247 | }
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248 | catch (IOException e) {
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249 | Console.traceln(Level.WARNING, "could not read commands of package " + packageName);
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250 | }
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251 | }
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252 |
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253 | for (String className : classNames) {
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254 | String commandStr =
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255 | className.substring(className.lastIndexOf('.') + cmdPrefix.length() + 1);
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256 |
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257 | // commands may be found twice as a package may be available twice on the
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258 | // class path. Therefore check, if the command was already dumped before
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259 | // dumping it.
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260 | if (!commands.contains(commandStr)) {
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261 | // class may still be inner classes. Therefore load the command, to
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262 | // see if it is really available and a command.
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263 | if (loadCMD(className) != null) {
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264 | commands.add(commandStr);
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265 | }
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266 | }
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267 | }
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268 |
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269 | String[] commandArray = commands.toArray(new String[commands.size()]);
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270 | Arrays.sort(commandArray);
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271 | return commandArray;
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272 | }
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273 | }
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