Java tutorial
/** * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You 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 org.apache.commons.cli; import java.io.File; import java.net.MalformedURLException; import java.net.URL; import java.util.Date; /** * This is a temporary implementation. TypeHandler will handle the * pluggableness of OptionTypes and it will direct all of these types * of conversion functionalities to ConvertUtils component in Commons * already. BeanUtils I think. * * @version $Revision: 741425 $, $Date: 2009-02-05 22:10:54 -0800 (Thu, 05 Feb 2009) $ */ public class TypeHandler { /** * Returns the <code>Object</code> of type <code>obj</code> * with the value of <code>str</code>. * * @param str the command line value * @param obj the type of argument * @return The instance of <code>obj</code> initialised with * the value of <code>str</code>. */ public static Object createValue(String str, Object obj) throws ParseException { return createValue(str, (Class) obj); } /** * Returns the <code>Object</code> of type <code>clazz</code> * with the value of <code>str</code>. * * @param str the command line value * @param clazz the type of argument * @return The instance of <code>clazz</code> initialised with * the value of <code>str</code>. */ public static Object createValue(String str, Class clazz) throws ParseException { if (PatternOptionBuilder.STRING_VALUE == clazz) { return str; } else if (PatternOptionBuilder.OBJECT_VALUE == clazz) { return createObject(str); } else if (PatternOptionBuilder.NUMBER_VALUE == clazz) { return createNumber(str); } else if (PatternOptionBuilder.DATE_VALUE == clazz) { return createDate(str); } else if (PatternOptionBuilder.CLASS_VALUE == clazz) { return createClass(str); } else if (PatternOptionBuilder.FILE_VALUE == clazz) { return createFile(str); } else if (PatternOptionBuilder.EXISTING_FILE_VALUE == clazz) { return createFile(str); } else if (PatternOptionBuilder.FILES_VALUE == clazz) { return createFiles(str); } else if (PatternOptionBuilder.URL_VALUE == clazz) { return createURL(str); } else { return null; } } /** * Create an Object from the classname and empty constructor. * * @param classname the argument value * @return the initialised object, or null if it couldn't create * the Object. */ public static Object createObject(String classname) throws ParseException { Class cl = null; try { cl = Class.forName(classname); } catch (ClassNotFoundException cnfe) { throw new ParseException("Unable to find the class: " + classname); } Object instance = null; try { instance = cl.newInstance(); } catch (Exception e) { throw new ParseException(e.getClass().getName() + "; Unable to create an instance of: " + classname); } return instance; } /** * Create a number from a String. If a . is present, it creates a * Double, otherwise a Long. * * @param str the value * @return the number represented by <code>str</code>, if <code>str</code> * is not a number, null is returned. */ public static Number createNumber(String str) throws ParseException { try { if (str.indexOf('.') != -1) { return Double.valueOf(str); } else { return Long.valueOf(str); } } catch (NumberFormatException e) { throw new ParseException(e.getMessage()); } } /** * Returns the class whose name is <code>classname</code>. * * @param classname the class name * @return The class if it is found, otherwise return null */ public static Class createClass(String classname) throws ParseException { try { return Class.forName(classname); } catch (ClassNotFoundException e) { throw new ParseException("Unable to find the class: " + classname); } } /** * Returns the date represented by <code>str</code>. * * @param str the date string * @return The date if <code>str</code> is a valid date string, * otherwise return null. */ public static Date createDate(String str) throws ParseException { throw new UnsupportedOperationException("Not yet implemented"); } /** * Returns the URL represented by <code>str</code>. * * @param str the URL string * @return The URL is <code>str</code> is well-formed, otherwise * return null. */ public static URL createURL(String str) throws ParseException { try { return new URL(str); } catch (MalformedURLException e) { throw new ParseException("Unable to parse the URL: " + str); } } /** * Returns the File represented by <code>str</code>. * * @param str the File location * @return The file represented by <code>str</code>. */ public static File createFile(String str) throws ParseException { return new File(str); } /** * Returns the File[] represented by <code>str</code>. * * @param str the paths to the files * @return The File[] represented by <code>str</code>. */ public static File[] createFiles(String str) throws ParseException { // to implement/port: // return FileW.findFiles(str); throw new UnsupportedOperationException("Not yet implemented"); } }