stringutils.java.svn-base

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	 *         delimiter (neither element includes the
	 *         delimiter); or <code>null</code> if the
	 *         delimiter wasn't found in the given input
	 *         String
	 */
	public static String[] split(String toSplit, String delimiter) {
		if (!hasLength(toSplit) || !hasLength(delimiter)) {
			return null;
		}
		int offset = toSplit.indexOf(delimiter);
		if (offset < 0) {
			return null;
		}
		String beforeDelimiter = toSplit.substring(0, offset);
		String afterDelimiter = toSplit.substring(offset + delimiter.length());
		return new String[] { beforeDelimiter, afterDelimiter };
	}

	/**
	 * Take an array Strings and split each element based on
	 * the given delimiter. A <code>Properties</code>
	 * instance is then generated, with the left of the
	 * delimiter providing the key, and the right of the
	 * delimiter providing the value.
	 * <p>
	 * Will trim both the key and value before adding them
	 * to the <code>Properties</code> instance.
	 * 
	 * @param array
	 *            the array to process
	 * @param delimiter
	 *            to split each element using (typically the
	 *            equals symbol)
	 * @return a <code>Properties</code> instance
	 *         representing the array contents, or
	 *         <code>null</code> if the array to process
	 *         was null or empty
	 */
	public static Properties splitArrayElementsIntoProperties(String[] array,
			String delimiter) {
		return splitArrayElementsIntoProperties(array, delimiter, null);
	}

	/**
	 * Take an array Strings and split each element based on
	 * the given delimiter. A <code>Properties</code>
	 * instance is then generated, with the left of the
	 * delimiter providing the key, and the right of the
	 * delimiter providing the value.
	 * <p>
	 * Will trim both the key and value before adding them
	 * to the <code>Properties</code> instance.
	 * 
	 * @param array
	 *            the array to process
	 * @param delimiter
	 *            to split each element using (typically the
	 *            equals symbol)
	 * @param charsToDelete
	 *            one or more characters to remove from each
	 *            element prior to attempting the split
	 *            operation (typically the quotation mark
	 *            symbol), or <code>null</code> if no
	 *            removal should occur
	 * @return a <code>Properties</code> instance
	 *         representing the array contents, or
	 *         <code>null</code> if the array to process
	 *         was null or empty
	 */
	public static Properties splitArrayElementsIntoProperties(String[] array,
			String delimiter, String charsToDelete) {

		if (array == null || array.length == 0) {
			return null;
		}

		Properties result = new Properties();
		for (int i = 0; i < array.length; i++) {
			String element = array[i];
			if (charsToDelete != null) {
				element = deleteAny(array[i], charsToDelete);
			}
			String[] splittedElement = split(element, delimiter);
			if (splittedElement == null) {
				continue;
			}
			result.setProperty(splittedElement[0].trim(), splittedElement[1]
					.trim());
		}
		return result;
	}

	/**
	 * Tokenize the given String into a String array via a
	 * StringTokenizer. Trims tokens and omits empty tokens.
	 * <p>
	 * The given delimiters string is supposed to consist of
	 * any number of delimiter characters. Each of those
	 * characters can be used to separate tokens. A
	 * delimiter is always a single character; for
	 * multi-character delimiters, consider using
	 * <code>delimitedListToStringArray</code>
	 * 
	 * @param str
	 *            the String to tokenize
	 * @param delimiters
	 *            the delimiter characters, assembled as
	 *            String (each of those characters is
	 *            individually considered as delimiter).
	 * @return an array of the tokens
	 * @see java.util.StringTokenizer
	 * @see java.lang.String#trim
	 * @see #delimitedListToStringArray
	 */
	public static String[] tokenizeToStringArray(String str, String delimiters) {
		return tokenizeToStringArray(str, delimiters, true, true);
	}

	/**
	 * Tokenize the given String into a String array via a
	 * StringTokenizer.
	 * <p>
	 * The given delimiters string is supposed to consist of
	 * any number of delimiter characters. Each of those
	 * characters can be used to separate tokens. A
	 * delimiter is always a single character; for
	 * multi-character delimiters, consider using
	 * <code>delimitedListToStringArray</code>
	 * 
	 * @param str
	 *            the String to tokenize
	 * @param delimiters
	 *            the delimiter characters, assembled as
	 *            String (each of those characters is
	 *            individually considered as delimiter)
	 * @param trimTokens
	 *            trim the tokens via String's
	 *            <code>trim</code>
	 * @param ignoreEmptyTokens
	 *            omit empty tokens from the result array
	 *            (only applies to tokens that are empty
	 *            after trimming; StringTokenizer will not
	 *            consider subsequent delimiters as token in
	 *            the first place).
	 * @return an array of the tokens
	 * @see java.util.StringTokenizer
	 * @see java.lang.String#trim
	 * @see #delimitedListToStringArray
	 */
	public static String[] tokenizeToStringArray(String str, String delimiters,
			boolean trimTokens, boolean ignoreEmptyTokens) {
		if (str == null) {
			return new String[] {};
		}
		StringTokenizer st = new StringTokenizer(str, delimiters);
		List tokens = new ArrayList();
		while (st.hasMoreTokens()) {
			String token = st.nextToken();
			if (trimTokens) {
				token = token.trim();
			}
			if (!ignoreEmptyTokens || token.length() > 0) {
				tokens.add(token);
			}
		}
		return toStringArray(tokens);
	}

	/**
	 * Take a String which is a delimited list and convert
	 * it to a String array.
	 * <p>
	 * A single delimiter can consists of more than one
	 * character: It will still be considered as single
	 * delimiter string, rather than as bunch of potential
	 * delimiter characters - in contrast to
	 * <code>tokenizeToStringArray</code>.
	 * 
	 * @param str
	 *            the input String
	 * @param delimiter
	 *            the delimiter between elements (this is a
	 *            single delimiter, rather than a bunch
	 *            individual delimiter characters)
	 * @return an array of the tokens in the list
	 * @see #tokenizeToStringArray
	 */
	public static String[] delimitedListToStringArray(String str,
			String delimiter) {
		if (str == null) {
			return new String[0];
		}
		if (delimiter == null) {
			return new String[] { str };
		}

		List result = new ArrayList();
		if ("".equals(delimiter)) {
			for (int i = 0; i < str.length(); i++) {
				result.add(str.substring(i, i + 1));
			}
		} else {
			int pos = 0;
			int delPos = 0;
			while ((delPos = str.indexOf(delimiter, pos)) != -1) {
				result.add(str.substring(pos, delPos));
				pos = delPos + delimiter.length();
			}
			if (str.length() > 0 && pos <= str.length()) {
				// Add rest of String, but not in case of
				// empty input.
				result.add(str.substring(pos));
			}
		}
		return toStringArray(result);
	}

	/**
	 * Convert a CSV list into an array of Strings.
	 * 
	 * @param str
	 *            CSV list
	 * @return an array of Strings, or the empty array if s
	 *         is null
	 */
	public static String[] commaDelimitedListToStringArray(String str) {
		return delimitedListToStringArray(str, ",");
	}

	/**
	 * Convenience method to convert a CSV string list to a
	 * set. Note that this will suppress duplicates.
	 * 
	 * @param str
	 *            CSV String
	 * @return a Set of String entries in the list
	 */
	public static Set commaDelimitedListToSet(String str) {
		Set set = new TreeSet();
		String[] tokens = commaDelimitedListToStringArray(str);
		for (int i = 0; i < tokens.length; i++) {
			set.add(tokens[i]);
		}
		return set;
	}

	/**
	 * Convenience method to return a String array as a
	 * delimited (e.g. CSV) String. E.g. useful for
	 * toString() implementations.
	 * 
	 * @param arr
	 *            array to display. Elements may be of any
	 *            type (toString will be called on each
	 *            element).
	 * @param delim
	 *            delimiter to use (probably a ",")
	 */
	public static String arrayToDelimitedString(Object[] arr, String delim) {
		if (arr == null) {
			return "";
		}

		StringBuffer sb = new StringBuffer();
		for (int i = 0; i < arr.length; i++) {
			if (i > 0) {
				sb.append(delim);
			}
			sb.append(arr[i]);
		}
		return sb.toString();
	}

	/**
	 * Convenience method to return a Collection as a
	 * delimited (e.g. CSV) String. E.g. useful for
	 * toString() implementations.
	 * 
	 * @param coll
	 *            Collection to display
	 * @param delim
	 *            delimiter to use (probably a ",")
	 * @param prefix
	 *            string to start each element with
	 * @param suffix
	 *            string to end each element with
	 */
	public static String collectionToDelimitedString(Collection coll,
			String delim, String prefix, String suffix) {
		if (coll == null) {
			return "";
		}

		StringBuffer sb = new StringBuffer();
		Iterator it = coll.iterator();
		int i = 0;
		while (it.hasNext()) {
			if (i > 0) {
				sb.append(delim);
			}
			sb.append(prefix).append(it.next()).append(suffix);
			i++;
		}
		return sb.toString();
	}

	/**
	 * Convenience method to return a Collection as a
	 * delimited (e.g. CSV) String. E.g. useful for
	 * toString() implementations.
	 * 
	 * @param coll
	 *            Collection to display
	 * @param delim
	 *            delimiter to use (probably a ",")
	 */
	public static String collectionToDelimitedString(Collection coll,
			String delim) {
		return collectionToDelimitedString(coll, delim, "", "");
	}

	/**
	 * Convenience method to return a String array as a CSV
	 * String. E.g. useful for toString() implementations.
	 * 
	 * @param arr
	 *            array to display. Elements may be of any
	 *            type (toString will be called on each
	 *            element).
	 */
	public static String arrayToCommaDelimitedString(Object[] arr) {
		return arrayToDelimitedString(arr, ",");
	}

	/**
	 * Convenience method to return a Collection as a CSV
	 * String. E.g. useful for toString() implementations.
	 * 
	 * @param coll
	 *            Collection to display
	 */
	public static String collectionToCommaDelimitedString(Collection coll) {
		return collectionToDelimitedString(coll, ",");
	}

}