/*
    * Copyright 2006-2007 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 org.springframework.batch.support;
  
  import java.io.IOException;
  import java.io.StringReader;
  import java.io.StringWriter;
  import java.util.Arrays;
  import java.util.List;
  import java.util.Properties;
  
  import org.springframework.util.DefaultPropertiesPersister;
  import org.springframework.util.PropertiesPersister;
  import org.springframework.util.StringUtils;
  
  /**
   * Utility to convert a Properties object to a String and back. Ideally this
   * utility should have been used to convert to string in order to convert that
   * string back to a Properties Object. Attempting to convert a string obtained
   * by calling Properties.toString() will return an invalid Properties object.
   * The format of Properties is that used by {@link PropertiesPersister} from the
   * Spring Core, so a String in the correct format for a Spring property editor
   * is fine (key=value pairs separated by new lines).
   * 
   * @author Lucas Ward
   * @author Dave Syer
   * 
   * @see PropertiesPersister
   */
  public final class PropertiesConverter {
  
  	private static final PropertiesPersister propertiesPersister = new DefaultPropertiesPersister();
  
  	private static final String LINE_SEPARATOR = System.getProperty("line.separator");
  
  	// prevents the class from being instantiated
  	private PropertiesConverter() {
  	};
  
  	/**
  	 * Parse a String to a Properties object. If string is null, an empty
  	 * Properties object will be returned. The input String is a set of
  	 * name=value pairs, delimited by either newline or comma (for brevity). If
  	 * the input String contains a newline it is assumed that the separator is
  	 * newline, otherwise comma.
  	 * 
  	 * @param stringToParse String to parse.
  	 * @return Properties parsed from each string.
  	 * @see PropertiesPersister
  	 */
  	public static Properties stringToProperties(String stringToParse) {
  
  		if (stringToParse == null) {
  			return new Properties();
  		}
  
  		if (!contains(stringToParse, "\n")) {
  			stringToParse = StringUtils.arrayToDelimitedString(
  					StringUtils.commaDelimitedListToStringArray(stringToParse), "\n");
  		}
  
  		StringReader stringReader = new StringReader(stringToParse);
  
  		Properties properties = new Properties();
  
  		try {
  			propertiesPersister.load(properties, stringReader);
  			// Exception is only thrown by StringReader after it is closed,
  			// so never in this case.
  		}
  		catch (IOException ex) {
  			throw new IllegalStateException("Error while trying to parse String to java.util.Properties,"
  					+ " given String: " + properties);
  		}
  
  		return properties;
  	}
  
  	/**
  	 * Convert Properties object to String. This is only necessary for
  	 * compatibility with converting the String back to a properties object. If
  	 * an empty properties object is passed in, a blank string is returned,
  	 * otherwise it's string representation is returned.
  	 * 
  	 * @param propertiesToParse
 	 * @return String representation of properties object
 	 */
 	public static String propertiesToString(Properties propertiesToParse) {
 
 		// If properties is empty, return a blank string.
 		if (propertiesToParse == null || propertiesToParse.size() == 0) {
 			return "";
 		}
 
 		StringWriter stringWriter = new StringWriter();
 
 		try {
 			propertiesPersister.store(propertiesToParse, stringWriter, null);
 		}
 		catch (IOException ex) {
 			// Exception is never thrown by StringWriter
 			throw new IllegalStateException("Error while trying to convert properties to string");
 		}
 
 		// If the value is short enough (and doesn't contain commas), convert to
 		// comma-separated...
 		String value = stringWriter.toString();
 		if (value.length() < 160) {
 			List<String> list = Arrays.asList(StringUtils.delimitedListToStringArray(value, LINE_SEPARATOR,
 					LINE_SEPARATOR));
 			String shortValue = StringUtils.collectionToCommaDelimitedString(list.subList(1, list.size()));
 			int count = StringUtils.countOccurrencesOf(shortValue, ",");
 			if (count == list.size() - 2) {
 				value = shortValue;
 			}
 			if (value.endsWith(",")) {
 				value = value.substring(0, value.length() - 1);
 			}
 		}
 		return value;
 	}
 
 	private static boolean contains(String str, String searchStr) {
 		return str.indexOf(searchStr) != -1;
 	}
 }