1 | // Copyright 2012 Georg-August-Universität Göttingen, Germany
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2 | //
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3 | // Licensed under the Apache License, Version 2.0 (the "License");
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4 | // you may not use this file except in compliance with the License.
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5 | // You may obtain a copy of the License at
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6 | //
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7 | // http://www.apache.org/licenses/LICENSE-2.0
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8 | //
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9 | // Unless required by applicable law or agreed to in writing, software
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10 | // distributed under the License is distributed on an "AS IS" BASIS,
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11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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12 | // See the License for the specific language governing permissions and
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13 | // limitations under the License.
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14 |
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15 |
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16 | package de.ugoe.cs.util.console;
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17 |
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18 | import java.io.File;
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19 | import java.io.FileInputStream;
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20 | import java.io.FilenameFilter;
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21 | import java.io.IOException;
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22 | import java.net.URL;
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23 | import java.util.ArrayList;
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24 | import java.util.Comparator;
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25 | import java.util.Enumeration;
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26 | import java.util.List;
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27 | import java.util.SortedSet;
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28 | import java.util.TreeSet;
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29 | import java.util.jar.JarEntry;
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30 | import java.util.jar.JarInputStream;
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31 | import java.util.logging.Level;
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32 |
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33 | /**
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34 | * <p>
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35 | * Executes commands. The commands have to implement the {@link Command} interface and be in
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36 | * packages registered using addCommandPackage(). Additionally, default commands are implemented in
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37 | * the de.ugoe.cs.util.console.defaultcommands package.
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38 | * </p>
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39 | * <p>
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40 | * This class is implemented as a <i>Singleton</i>.
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41 | * </p>
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42 | *
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43 | * @author Steffen Herbold
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44 | * @version 1.0
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45 | */
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46 | public class CommandExecuter {
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47 |
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48 | /**
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49 | * <p>
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50 | * Handle of the CommandExecuter instance.
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51 | * </p>
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52 | */
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53 | private final static CommandExecuter theInstance = new CommandExecuter();
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54 |
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55 | /**
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56 | * <p>
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57 | * Prefix of all command classes.
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58 | * </p>
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59 | */
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60 | private static final String cmdPrefix = "CMD";
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61 |
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62 | /**
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63 | * <p>
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64 | * Name of the package for default commands.
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65 | * </p>
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66 | */
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67 | private static final String defaultPackage = "de.ugoe.cs.util.console.defaultcommands";
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68 |
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69 | /**
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70 | * <p>
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71 | * List of packages in which commands may be defined. The exec methods trys to load command from
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72 | * these packages in the order they have been added.
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73 | * </p>
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74 | * <p>
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75 | * The de.ugoe.cs.util.console.defaultcommands package has always lowest priority, unless it is
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76 | * specifically added.
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77 | * </p>
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78 | */
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79 | private List<String> commandPackageList;
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80 |
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81 | /**
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82 | * <p>
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83 | * the list of available commands (lazy instantiation in the method
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84 | * {@link #getAvailableCommands()})
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85 | * <p>
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86 | */
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87 | private Command[] availableCommands;
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88 |
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89 | /**
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90 | * <p>
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91 | * Returns the instance of CommandExecuter. If no instances exists yet, a new one is created.
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92 | * </p>
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93 | *
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94 | * @return the instance of CommandExecuter
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95 | */
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96 | public static synchronized CommandExecuter getInstance() {
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97 | return theInstance;
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98 | }
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99 |
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100 | /**
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101 | * <p>
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102 | * Creates a new CommandExecuter. Private to prevent multiple instances (Singleton).
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103 | * </p>
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104 | */
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105 | private CommandExecuter() {
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106 | commandPackageList = new ArrayList<String>();
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107 | }
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108 |
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109 | /**
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110 | * <p>
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111 | * Adds a package that will be used by {@link #exec(String)} to load command from.
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112 | * </p>
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113 | *
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114 | * @param pkg
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115 | * package where commands are located
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116 | * @throws IllegalArgumentException
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117 | * thrown if the package name is null or empty string
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118 | */
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119 | public void addCommandPackage(String pkg) {
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120 | if ("".equals(pkg) || pkg == null) {
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121 | throw new IllegalArgumentException("package name must not be null or empty string");
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122 | }
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123 | commandPackageList.add(pkg);
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124 | }
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125 |
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126 | /**
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127 | * <p>
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128 | * Executes the command defined by string. A command has the following form (mix of EBNF and
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129 | * natural language):
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130 | * </p>
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131 | * <code>
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132 | * <command> := <commandname><whitespace>{<parameter>}<br>
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133 | * <commandname> := String without whitespaces. Has to be a valid Java class name<br>
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134 | * <parameter> := <string>|<stringarray><br>
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135 | * <string> := <stringwithoutwhitespaces>|<stringwithwhitespaces>
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136 | * <stringwithoutwhitespaces> := a string without whitespaces<br>
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137 | * <stringwithoutwhitespaces> := a string, that can have whitespaces, but must be in double quotes<br>
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138 | * <stringarray> := "["<string>{<whitespace><string>"]"
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139 | * </code>
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140 | *
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141 | * @param command
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142 | * the command as a string
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143 | */
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144 | public void exec(String command) {
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145 | Console.commandNotification(command);
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146 | Command cmd = null;
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147 | CommandParser parser = new CommandParser();
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148 | parser.parse(command);
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149 | for (int i = 0; cmd == null && i < commandPackageList.size(); i++) {
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150 | cmd = loadCMD(commandPackageList.get(i) + "." + cmdPrefix + parser.getCommandName());
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151 | }
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152 | if (cmd == null) { // check if command is available as default command
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153 | cmd = loadCMD(defaultPackage + "." + cmdPrefix + parser.getCommandName());
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154 | }
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155 | if (cmd == null) {
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156 | Console.println("Unknown command");
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157 | }
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158 | else {
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159 | try {
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160 | cmd.run(parser.getParameters());
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161 | }
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162 | catch (IllegalArgumentException e) {
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163 | Console.println("Usage: " + cmd.help());
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164 | }
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165 | }
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166 | }
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167 |
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168 | /**
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169 | * <p>
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170 | * Helper method that loads a class and tries to cast it to {@link Command}.
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171 | * </p>
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172 | *
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173 | * @param className
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174 | * qualified name of the class (including package name)
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175 | * @return if class is available and implement {@link Command} and instance of the class, null
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176 | * otherwise
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177 | */
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178 | public Command loadCMD(String className) {
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179 | Command cmd = null;
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180 | try {
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181 | Class<?> cmdClass = Class.forName(className);
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182 | cmd = (Command) cmdClass.newInstance();
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183 | }
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184 | catch (NoClassDefFoundError e) {
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185 | String[] splitResult = e.getMessage().split("CMD");
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186 | String correctName = splitResult[splitResult.length - 1].replace(")", "");
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187 | Console.println("Did you mean " + correctName + "?");
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188 | }
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189 | catch (ClassNotFoundException e) {}
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190 | catch (IllegalAccessException e) {}
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191 | catch (InstantiationException e) {}
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192 | catch (ClassCastException e) {
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193 | Console.traceln(Level.WARNING, className + "found, but does not implement Command");
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194 | }
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195 | return cmd;
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196 | }
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197 |
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198 | /**
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199 | * <p>
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200 | * Helper method that loads a class and tries to cast it to {@link Command}.
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201 | * </p>
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202 | *
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203 | * @param className
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204 | * qualified name of the class (including package name)
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205 | * @return if class is available and implement {@link Command} and instance of the class, null
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206 | * otherwise
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207 | */
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208 | public Command getCMD(String commandName) {
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209 | Command cmd = null;
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210 | for (int i = 0; cmd == null && i < commandPackageList.size(); i++) {
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211 | cmd = loadCMD(commandPackageList.get(i) + "." + cmdPrefix + commandName);
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212 | }
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213 | if (cmd == null) { // check if command is available as default command
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214 | cmd = loadCMD(defaultPackage + "." + cmdPrefix + commandName);
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215 | }
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216 | return cmd;
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217 | }
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218 |
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219 | /**
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220 | * <p>
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221 | * reads all available commands from the registered command packages and returns a list of their
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222 | * names
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223 | * </p>
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224 | *
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225 | * @return an array containing the names of the available commands.
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226 | */
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227 | public Command[] getAvailableCommands() {
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228 | if (availableCommands == null) {
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229 | List<Command> commands = new ArrayList<Command>();
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230 | List<String> packages = new ArrayList<String>();
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231 | packages.addAll(commandPackageList);
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232 | packages.add(defaultPackage);
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233 |
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234 | FilenameFilter filter = new FilenameFilter() {
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235 | @Override
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236 | public boolean accept(File dir, String name) {
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237 | return
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238 | (name != null) && (name.startsWith(cmdPrefix)) && (name.endsWith(".class"));
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239 | }
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240 | };
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241 |
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242 | SortedSet<String> classNames = new TreeSet<String>(new Comparator<String>() {
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243 | @Override
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244 | public int compare(String arg1, String arg2) {
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245 | String str1 = arg1.substring(arg1.lastIndexOf('.') + cmdPrefix.length() + 1);
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246 | String str2 = arg2.substring(arg2.lastIndexOf('.') + cmdPrefix.length() + 1);
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247 | return str1.compareTo(str2);
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248 | }
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249 |
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250 | });
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251 |
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252 | for (String packageName : packages) {
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253 | String path = packageName.replace('.', '/');
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254 | try {
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255 | Enumeration<URL> resources = ClassLoader.getSystemResources(path);
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256 |
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257 | while (resources.hasMoreElements()) {
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258 | URL resource = resources.nextElement();
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259 | File packageDir = new File(resource.getFile());
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260 |
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261 | if (packageDir.isDirectory()) {
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262 | for (File classFile : packageDir.listFiles(filter)) {
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263 | String className = classFile.getName().substring
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264 | (0, classFile.getName().lastIndexOf('.'));
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265 | classNames.add(packageName + "." + className);
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266 | }
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267 | }
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268 | else {
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269 | int index = resource.getFile().lastIndexOf('!');
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270 | if ((index > 0) && (resource.getFile().startsWith("file:")) &&
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271 | (resource.getFile().endsWith("!/" + path)))
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272 | {
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273 | String jarFile =
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274 | resource.getFile().substring("file:".length(), index);
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275 |
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276 | // we have to read the package content from a jar file
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277 | JarInputStream jarInputStream = null;
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278 | try {
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279 | jarInputStream =
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280 | new JarInputStream(new FileInputStream(jarFile));
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281 | JarEntry entry = null;
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282 | do {
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283 | entry = jarInputStream.getNextJarEntry();
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284 | if ((entry != null) && (!entry.isDirectory()) &&
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285 | (entry.getName().startsWith(path)))
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286 | {
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287 | String className = entry.getName().substring
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288 | (path.length() + 1, entry.getName().lastIndexOf('.'));
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289 | classNames.add(packageName + "." + className);
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290 | }
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291 | }
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292 | while (entry != null);
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293 | }
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294 | catch (Exception e) {
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295 | e.printStackTrace();
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296 | Console.traceln(Level.WARNING, "could not read contents of " +
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297 | "jar " + jarFile);
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298 | }
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299 | finally {
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300 | if (jarInputStream != null) {
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301 | jarInputStream.close();
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302 | }
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303 | }
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304 |
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305 | }
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306 | }
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307 | }
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308 | }
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309 | catch (IOException e) {
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310 | Console.traceln
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311 | (Level.WARNING, "could not read commands of package " + packageName);
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312 | }
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313 | }
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314 |
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315 | for (String className : classNames) {
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316 | // class may still be inner classes. Therefore load the command, to
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317 | // see if it is really available and a command.
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318 | Command cmd = loadCMD(className);
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319 | if (cmd != null) {
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320 | commands.add(cmd);
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321 | }
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322 | }
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323 |
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324 | availableCommands = commands.toArray(new Command[commands.size()]);
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325 | }
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326 |
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327 | return availableCommands;
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328 | }
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329 |
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330 | /**
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331 | * <p>
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332 | * Get a copy of the currently registered command packages.
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333 | * </p>
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334 | *
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335 | * @return currently registered command packages
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336 | */
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337 | public List<String> getCommandPackages() {
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338 | List<String> commandPackageListCopy = new ArrayList<String>(commandPackageList);
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339 | commandPackageListCopy.add(0, defaultPackage);
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340 | return commandPackageListCopy;
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341 | }
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342 |
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343 | /**
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344 | * <p>
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345 | * this method method performs an auto completion of the provided String as far as possible
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346 | * regarding the available commands. It auto completes to the full command name, if only
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347 | * one command matches the given prefix. It auto completes to the common denominator, if
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348 | * several commands match the prefix
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349 | * </p>
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350 | *
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351 | * @param commandPrefix the prefix to be auto completed
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352 | *
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353 | * @return as described
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354 | */
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355 | public String autoCompleteCommand(String commandPrefix) {
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356 | Command[] commands = getAvailableCommands();
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357 |
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358 | List<Command> matchingCommands = new ArrayList<Command>();
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359 | for (Command command : commands) {
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360 | String commandName = command.getClass().getSimpleName().substring(3);
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361 | if (commandName.startsWith(commandPrefix)) {
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362 | matchingCommands.add(command);
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363 | }
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364 | }
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365 |
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366 | StringBuffer completedPrefix = new StringBuffer(commandPrefix);
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367 |
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368 | boolean foundCompletion = false;
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369 |
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370 | while (!foundCompletion) {
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371 | char nextCompletionChar = 0;
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372 | for (Command command : matchingCommands) {
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373 | String commandName = command.getClass().getSimpleName().substring(3);
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374 | if (commandName.length() > completedPrefix.length()) {
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375 | if (nextCompletionChar == 0) {
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376 | nextCompletionChar = commandName.charAt(completedPrefix.length());
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377 | }
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378 | else if (nextCompletionChar != commandName.charAt(completedPrefix.length())) {
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379 | foundCompletion = true;
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380 | }
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381 | }
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382 | else {
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383 | foundCompletion = true;
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384 | }
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385 | }
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386 |
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387 | if (!foundCompletion && (nextCompletionChar != 0)) {
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388 | completedPrefix.append(nextCompletionChar);
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389 | }
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390 | else {
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391 | foundCompletion = true;
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392 | }
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393 | }
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394 |
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395 | return completedPrefix.toString();
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396 | }
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397 | }
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