Java tutorial
/* * MIT License * * Copyright (c) 2016 Asynchronous Game Query Library * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in all * copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NON INFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. */ package com.ibasco.agql.examples.base; import com.ibasco.agql.core.exceptions.AsyncGameLibUncheckedException; import org.apache.commons.lang3.BooleanUtils; import org.apache.commons.lang3.StringUtils; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import javax.crypto.Cipher; import javax.crypto.spec.IvParameterSpec; import javax.crypto.spec.SecretKeySpec; import java.io.*; import java.util.Base64; import java.util.Properties; import java.util.Scanner; abstract public class BaseExample implements Closeable { private static final String worldsMostSecureUnhackableIvKey = "aGqLsOurc3querYs"; private static String worldsMostSecureUnhackableKey = "0123456789abcdef"; private static final Logger log = LoggerFactory.getLogger(BaseExample.class); private static final String EXAMPLE_PROP_FILE = "example.properties"; private Properties exampleProps = new Properties(); abstract public void run() throws Exception; public BaseExample() { loadProps(); } private void loadProps() { InputStream is; // First try loading from the current directory try { File f = new File(EXAMPLE_PROP_FILE); is = new FileInputStream(f); } catch (Exception e) { is = null; } try { if (is == null) { // Try loading from classpath is = getClass().getResourceAsStream(EXAMPLE_PROP_FILE); } if (is == null) { File f = new File(EXAMPLE_PROP_FILE); OutputStream out = new FileOutputStream(f); exampleProps.store(out, "AUTO GENERATED FILE"); } // Try loading properties from the file (if found) exampleProps.load(is); } catch (Exception e) { } } public void saveProp(String property, String value) { try { String tmpValue = value == null ? "null" : value; exampleProps.setProperty(property, tmpValue); File f = new File(EXAMPLE_PROP_FILE); OutputStream out = new FileOutputStream(f); exampleProps.store(out, String.format("From '%s'", this.getClass().getSimpleName())); } catch (Exception e) { e.printStackTrace(); } } protected String getProp(String propertyName) { String tmp = exampleProps.getProperty(propertyName); return "null".equalsIgnoreCase(tmp) ? null : tmp; } protected String promptInput(String message, boolean required) { return promptInput(message, required, null); } protected Boolean promptInputBool(String message, boolean required, String defaultReturnValue) { return promptInputBool(message, required, defaultReturnValue, null); } protected Boolean promptInputBool(String message, boolean required, String defaultReturnValue, String defaultProperty) { String tmpVal = promptInput(message, required, defaultReturnValue, defaultProperty); return tmpVal != null ? BooleanUtils.toBoolean(tmpVal) : null; } protected String promptInput(String message, boolean required, String defaultReturnValue) { return promptInput(message, required, defaultReturnValue, null); } @SuppressWarnings("unchecked") protected String promptInput(String message, boolean required, String defaultReturnValue, String defaultProperty) { Scanner userInput = new Scanner(System.in); String returnValue; //perform some bit of magic to determine if the prompt is a password type boolean inputEmpty, isPassword = StringUtils.containsIgnoreCase(message, "password"); int retryCounter = 0; String defaultValue = defaultReturnValue; //Get value from file (if available) if (!StringUtils.isEmpty(defaultProperty)) { if (isPassword) { try { String defaultProp = getProp(defaultProperty); if (!StringUtils.isEmpty(defaultProp)) defaultValue = decrypt(defaultProp); } catch (Exception e) { throw new AsyncGameLibUncheckedException(e); } } else { defaultValue = getProp(defaultProperty); } } do { if (!StringUtils.isEmpty(defaultValue)) { if (isPassword) { System.out.printf("%s [%s]: ", message, StringUtils.replaceAll(defaultValue, ".", "*")); } else System.out.printf("%s [%s]: ", message, defaultValue); } else { System.out.printf("%s: ", message); } System.out.flush(); returnValue = StringUtils.defaultIfEmpty(userInput.nextLine(), defaultValue); inputEmpty = StringUtils.isEmpty(returnValue); } while ((inputEmpty && ++retryCounter < 3) && required); //If the token is still empty, throw an error if (inputEmpty && required) { System.err.println("Required parameter is missing"); } else if (inputEmpty && !StringUtils.isEmpty(defaultValue)) { returnValue = defaultValue; } //Save to properties file if (!StringUtils.isEmpty(defaultProperty)) { if (isPassword) { try { saveProp(defaultProperty, encrypt(returnValue)); } catch (Exception e) { throw new AsyncGameLibUncheckedException(e); } } else { saveProp(defaultProperty, returnValue); } } return returnValue; } /** * @see <a href="https://gist.github.com/bricef/2436364">https://gist.github.com/bricef/2436364</a> */ public static String encrypt(String plainText) throws Exception { Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding", "SunJCE"); SecretKeySpec key = new SecretKeySpec(worldsMostSecureUnhackableKey.getBytes("UTF-8"), "AES"); cipher.init(Cipher.ENCRYPT_MODE, key, new IvParameterSpec(worldsMostSecureUnhackableIvKey.getBytes("UTF-8"))); return Base64.getEncoder().encodeToString((cipher.doFinal(padNullBytes(plainText)))); } /** * @see <a href="https://gist.github.com/bricef/2436364">https://gist.github.com/bricef/2436364</a> */ public static String decrypt(String cipherText) throws Exception { Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding", "SunJCE"); SecretKeySpec key = new SecretKeySpec(worldsMostSecureUnhackableKey.getBytes("UTF-8"), "AES"); cipher.init(Cipher.DECRYPT_MODE, key, new IvParameterSpec(worldsMostSecureUnhackableIvKey.getBytes("UTF-8"))); byte[] cipherBytes = Base64.getDecoder().decode(cipherText); return new String(cipher.doFinal(cipherBytes), "UTF-8"); } private static byte[] padNullBytes(String text) { if (StringUtils.isEmpty(text)) return null; ByteArrayOutputStream bos = new ByteArrayOutputStream(); try { bos.write(text.getBytes("UTF-8")); while ((bos.size() % 16) != 0) { bos.write(0); } } catch (IOException e) { throw new AsyncGameLibUncheckedException(e); } return bos.toByteArray(); } }