1 /* 2 ** 3 ** Copyright 2013, The Android Open Source Project 4 ** 5 ** Licensed under the Apache License, Version 2.0 (the "License"); 6 ** you may not use this file except in compliance with the License. 7 ** You may obtain a copy of the License at 8 ** 9 ** http://www.apache.org/licenses/LICENSE-2.0 10 ** 11 ** Unless required by applicable law or agreed to in writing, software 12 ** distributed under the License is distributed on an "AS IS" BASIS, 13 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 ** See the License for the specific language governing permissions and 15 ** limitations under the License. 16 */ 17 18 package com.android.internal.os; 19 20 import java.io.PrintStream; 21 22 public abstract class BaseCommand { 23 24 protected String[] mArgs; 25 private int mNextArg; 26 private String mCurArgData; 27 28 // These are magic strings understood by the Eclipse plugin. 29 public static final String FATAL_ERROR_CODE = "Error type 1"; 30 public static final String NO_SYSTEM_ERROR_CODE = "Error type 2"; 31 public static final String NO_CLASS_ERROR_CODE = "Error type 3"; 32 33 /** 34 * Call to run the command. 35 */ run(String[] args)36 public void run(String[] args) { 37 if (args.length < 1) { 38 onShowUsage(System.out); 39 return; 40 } 41 42 mArgs = args; 43 mNextArg = 0; 44 mCurArgData = null; 45 46 try { 47 onRun(); 48 } catch (IllegalArgumentException e) { 49 onShowUsage(System.err); 50 System.err.println(); 51 System.err.println("Error: " + e.getMessage()); 52 } catch (Exception e) { 53 e.printStackTrace(System.err); 54 System.exit(1); 55 } 56 } 57 58 /** 59 * Convenience to show usage information to error output. 60 */ showUsage()61 public void showUsage() { 62 onShowUsage(System.err); 63 } 64 65 /** 66 * Convenience to show usage information to error output along 67 * with an error message. 68 */ showError(String message)69 public void showError(String message) { 70 onShowUsage(System.err); 71 System.err.println(); 72 System.err.println(message); 73 } 74 75 /** 76 * Implement the command. 77 */ onRun()78 public abstract void onRun() throws Exception; 79 80 /** 81 * Print help text for the command. 82 */ onShowUsage(PrintStream out)83 public abstract void onShowUsage(PrintStream out); 84 85 /** 86 * Return the next option on the command line -- that is an argument that 87 * starts with '-'. If the next argument is not an option, null is returned. 88 */ nextOption()89 public String nextOption() { 90 if (mCurArgData != null) { 91 String prev = mArgs[mNextArg - 1]; 92 throw new IllegalArgumentException("No argument expected after \"" + prev + "\""); 93 } 94 if (mNextArg >= mArgs.length) { 95 return null; 96 } 97 String arg = mArgs[mNextArg]; 98 if (!arg.startsWith("-")) { 99 return null; 100 } 101 mNextArg++; 102 if (arg.equals("--")) { 103 return null; 104 } 105 if (arg.length() > 1 && arg.charAt(1) != '-') { 106 if (arg.length() > 2) { 107 mCurArgData = arg.substring(2); 108 return arg.substring(0, 2); 109 } else { 110 mCurArgData = null; 111 return arg; 112 } 113 } 114 mCurArgData = null; 115 return arg; 116 } 117 118 /** 119 * Return the next argument on the command line, whatever it is; if there are 120 * no arguments left, return null. 121 */ nextArg()122 public String nextArg() { 123 if (mCurArgData != null) { 124 String arg = mCurArgData; 125 mCurArgData = null; 126 return arg; 127 } else if (mNextArg < mArgs.length) { 128 return mArgs[mNextArg++]; 129 } else { 130 return null; 131 } 132 } 133 134 /** 135 * Return the next argument on the command line, whatever it is; if there are 136 * no arguments left, throws an IllegalArgumentException to report this to the user. 137 */ nextArgRequired()138 public String nextArgRequired() { 139 String arg = nextArg(); 140 if (arg == null) { 141 String prev = mArgs[mNextArg - 1]; 142 throw new IllegalArgumentException("Argument expected after \"" + prev + "\""); 143 } 144 return arg; 145 } 146 } 147