Java tutorial
/* * ObjectLab, http://www.objectlab.co.uk/open is sponsoring the ObjectLab Kit. * * Based in London, we are world leaders in the design and development * of bespoke applications for the securities financing markets. * * <a href="http://www.objectlab.co.uk/open">Click here to learn more</a> * ___ _ _ _ _ _ * / _ \| |__ (_) ___ ___| |_| | __ _| |__ * | | | | '_ \| |/ _ \/ __| __| | / _` | '_ \ * | |_| | |_) | | __/ (__| |_| |__| (_| | |_) | * \___/|_.__// |\___|\___|\__|_____\__,_|_.__/ * |__/ * * www.ObjectLab.co.uk * * $Id: AbstractDateCalculator.java 309 2010-03-23 21:01:49Z marchy $ * * Copyright 2006 the original author or authors. * * Licensed under the Apache License, Version 2.0 (the "License"); you may not * use this file except in compliance with the License. You may obtain a copy of * the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations under * the License. */ package net.objectlab.kit.console; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.io.PrintStream; import java.lang.reflect.Method; import java.math.BigDecimal; import java.text.ParseException; import java.text.SimpleDateFormat; import java.util.ArrayList; import java.util.Date; import java.util.List; import org.apache.commons.lang.StringUtils; import org.joda.time.LocalDate; /** * @author Benoit Xhenseval * */ public class ConsoleMenu { private static final int EXIT_CODE = 0; private static final int SCREEN_COLUMNS = 110; private static final int COL = 10; private static final PrintStream OUT = System.out; // ~ Instance fields // ------------------------------------------------------------------------------------------------ private final List<String> menu = new ArrayList<String>(); private final List<String> methods = new ArrayList<String>(); private final List<Boolean> askForRepeat = new ArrayList<Boolean>(); private final Repeater target; private int screenColumns = SCREEN_COLUMNS; // ~ Constructors // --------------------------------------------------------------------------------------------------- /** * @param containingObject * the object that will be called back once an option is chosen * in the menu */ public ConsoleMenu(final Repeater containingObject) { target = containingObject; } // ~ Methods // -------------------------------------------------------------------------------------------------------- /** * add an entry in the menu, sequentially * * @param menuDisplay * how the entry will be displayed in the menu * @param methodName * name of the public method * @param repeat call back for repeat */ public void addMenuItem(final String menuDisplay, final String methodName, final boolean repeat) { menu.add(menuDisplay); methods.add(methodName); askForRepeat.add(Boolean.valueOf(repeat)); } public void setScreenColumns(final int width) { screenColumns = width; } /** * display the menu, the application goes into a loop which provides the * menu and fires the entries selected. It automatically adds an entry to * exit. */ public void displayMenu() { while (true) { ConsoleMenu.println(""); ConsoleMenu.println("Menu Options"); final int size = menu.size(); displayMenu(size); int opt = -1; do { opt = ConsoleMenu.getInt("Enter your choice:", -1); } while ((opt <= 0 || opt > methods.size()) && opt != EXIT_CODE); if (opt == EXIT_CODE) { ConsoleMenu.println("Exiting menu"); try { final Method meth = target.getClass().getMethod("tearDown", new Class[0]); if (meth != null) { meth.invoke(target, new Object[0]); } } catch (final Exception e) { log(e); } return; } // now call the method final String method = methods.get(opt - 1); final Boolean repeat = askForRepeat.get(opt - 1); try { final Method meth = target.getClass().getMethod(method, new Class[0]); if (repeat) { target.repeat(meth); } else { meth.invoke(target, new Object[0]); } } catch (final Exception e) { log(e); } } } private static void log(final Exception e) { e.printStackTrace(); } private void displayMenu(final int size) { for (int i = 0; i < size / 2; i++) { final StringBuilder line = new StringBuilder(); final String col1 = menu.get(i); if (i + 1 < COL) { line.append(" "); } final int pos = i + 1; line.append(" ").append(pos).append(") ").append(col1); while (line.length() < screenColumns / 2) { line.append(" "); } if (i + size / 2 < size) { final String col2 = menu.get(i + size / 2); final int position = i + 1 + size / 2; line.append(" ").append(position).append(") ").append(col2); } ConsoleMenu.println(line.toString()); } if (size % 2 != 0) { final StringBuilder line = new StringBuilder(); final String col1 = menu.get(size - 1); if (size < COL) { line.append(" "); } line.append(" ").append(size).append(") ").append(col1); while (line.length() < screenColumns / 2) { line.append(" "); } line.append(" ").append(EXIT_CODE).append(") ").append("Exit"); ConsoleMenu.println(line.toString()); } else { ConsoleMenu.println(" " + EXIT_CODE + ") Exit"); } } /** * Gets an int from the System.in * @param title for the command line * @param defaultValue defaultValue if title not found * @return int as entered by the user of the console app */ public static int getInt(final String title, final int defaultValue) { int opt = -1; do { try { final String val = ConsoleMenu.getString(title + " (default:" + defaultValue + ")"); if (val.length() == 0) { opt = defaultValue; } else { opt = Integer.parseInt(val); } } catch (final NumberFormatException e) { opt = -1; } } while (opt == -1); return opt; } /** * Gets a boolean from the System.in * * @param title * for the command line * @return boolean as selected by the user of the console app */ public static boolean getBoolean(final String title, final boolean defaultValue) { final String val = ConsoleMenu.selectOne(title, new String[] { "Yes", "No" }, new String[] { Boolean.TRUE.toString(), Boolean.FALSE.toString() }, defaultValue ? 1 : 2); return Boolean.valueOf(val); } /** * Gets an BigDecimal from the System.in * * @param title * for the command line * @return int as entered by the user of the console app */ public static BigDecimal getBigDecimal(final String title, final BigDecimal defaultValue) { BigDecimal opt = null; do { try { final String val = ConsoleMenu.getString(title + " (default:" + defaultValue + ")"); if (val.length() == 0) { opt = defaultValue; } else { opt = new BigDecimal(val); } } catch (final NumberFormatException e) { opt = null; } } while (opt == null && defaultValue != null); return opt; } public static Date getDate(final String title, final Date defaultValue) { final SimpleDateFormat fmt = new SimpleDateFormat("dd-MM-yyyy"); final String date = ConsoleMenu.getString(title + "(dd-MM-yyyy" + (defaultValue != null ? ", default:" + fmt.format(defaultValue) : "") + ")"); try { if (date == null || date.length() == 0) { return defaultValue; } return fmt.parse(date); } catch (final ParseException e) { log(e); } return null; } public static LocalDate getYMD(final String title, final LocalDate defaultValue) { final Date dateStr = ConsoleMenu.getDate(title, defaultValue != null ? defaultValue.toDateMidnight().toDate() : null); if (dateStr != null) { return new LocalDate(dateStr); } return null; } /** * Gets a String from the System.in * * @param msg * for the command line * @return String as entered by the user of the console app */ public static String getString(final String msg) { ConsoleMenu.print(msg); BufferedReader bufReader = null; String opt = null; try { bufReader = new BufferedReader(new InputStreamReader(System.in)); opt = bufReader.readLine(); } catch (final IOException ex) { log(ex); System.exit(1); } return opt; } /** * Gets a String from the System.in * * @param msg * for the command line * @return String as entered by the user of the console app */ public static String getString(final String msg, final String defaultVal) { String s = getString(msg + "(default:" + defaultVal + "):"); if (StringUtils.isBlank(s)) { s = defaultVal; } return s; } /** * Generates a menu with a list of options and return the value selected. * * @param title * for the command line * @param optionNames * name for each option * @param optionValues * value for each option * @return String as selected by the user of the console app */ public static String selectOne(final String title, final String[] optionNames, final String[] optionValues, final int defaultOption) { if (optionNames.length != optionValues.length) { throw new IllegalArgumentException("option names and values must have same length"); } ConsoleMenu.println("Please chose " + title + " (default:" + defaultOption + ")"); for (int i = 0; i < optionNames.length; i++) { ConsoleMenu.println(i + 1 + ") " + optionNames[i]); } int choice = 0; do { choice = ConsoleMenu.getInt("Your Choice 1-" + optionNames.length + ": ", defaultOption); } while (choice <= 0 || choice > optionNames.length); return optionValues[choice - 1]; } /** * @param prompt * The prompt to display to the user. * @return The password as entered by the user. */ public static String getPassword(final String prompt) { try { // password holder final StringBuilder password = new StringBuilder(); final PasswordHidingThread maskingthread = new PasswordHidingThread(prompt); final Thread thread = new Thread(maskingthread); thread.start(); // block until enter is pressed while (true) { char c = (char) System.in.read(); // assume enter pressed, stop masking maskingthread.stopMasking(); if (c == '\r') { c = (char) System.in.read(); if (c == '\n') { break; } continue; } else if (c == '\n') { break; } else { // store the password password.append(c); } } return password.toString(); } catch (final IOException e) { log(e); } return null; } // ~ Inner Classes // -------------------------------------------------------------------------------------------------- /** * This class attempts to erase characters echoed to the console. */ static class PasswordHidingThread extends Thread { private boolean stop = false; private final String prompt; /** * @param prompt * The prompt displayed to the user */ public PasswordHidingThread(final String prompt) { this.prompt = prompt; } /** * Begin masking until asked to stop. */ @Override public void run() { while (!stop) { try { // attempt masking at this rate Thread.sleep(1); } catch (final InterruptedException iex) { log(iex); } if (!stop) { ConsoleMenu.print("\r" + prompt + " \r" + prompt); } System.out.flush(); } } /** * Instruct the thread to stop masking. */ public void stopMasking() { this.stop = true; } } private static void println(final String txt) { OUT.println(txt); } private static void print(final String txt) { OUT.print(txt); } }