diff -r 000000000000 -r fb9019fb1bf7 src/net/fortuna/ical4j/util/Strings.java
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/net/fortuna/ical4j/util/Strings.java Tue Feb 10 18:12:00 2015 +0100
@@ -0,0 +1,238 @@
+/**
+ * Copyright (c) 2012, Ben Fortuna
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * o Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * o Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * o Neither the name of Ben Fortuna nor the names of any other contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package net.fortuna.ical4j.util;
+
+import java.util.regex.Pattern;
+
+/**
+ * $Id$ [23-Apr-2004]
+ *
+ * Utility methods for working with parameters.
+ * @author Ben Fortuna
+ *
+ * 4.3.11 Text
+ *
+ * Value Name: TEXT
+ *
+ * Purpose This value type is used to identify values that contain human
+ * readable text.
+ *
+ * Formal Definition: The character sets supported by this revision of
+ * iCalendar are UTF-8 and US ASCII thereof. The applicability to other
+ * character sets is for future work. The value type is defined by the
+ * following notation.
+ *
+ * text = *(TSAFE-CHAR / ":" / DQUOTE / ESCAPED-CHAR)
+ * ; Folded according to description above
+ *
+ * ESCAPED-CHAR = "\\" / "\;" / "\," / "\N" / "\n")
+ * ; \\ encodes \, \N or \n encodes newline
+ * ; \; encodes ;, \, encodes ,
+ *
+ * TSAFE-CHAR = %x20-21 / %x23-2B / %x2D-39 / %x3C-5B
+ * %x5D-7E / NON-US-ASCII
+ * ; Any character except CTLs not needed by the current
+ * ; character set, DQUOTE, ";", ":", "\", ","
+ *
+ * Note: Certain other character sets may require modification of the
+ * above definitions, but this is beyond the scope of this document.
+ *
+ * Description: If the property permits, multiple "text" values are
+ * specified by a COMMA character (US-ASCII decimal 44) separated list
+ * of values.
+ *
+ * The language in which the text is represented can be controlled by
+ * the "LANGUAGE" property parameter.
+ *
+ * An intentional formatted text line break MUST only be included in a
+ * "TEXT" property value by representing the line break with the
+ * character sequence of BACKSLASH (US-ASCII decimal 92), followed by a
+ * LATIN SMALL LETTER N (US-ASCII decimal 110) or a LATIN CAPITAL LETTER
+ * N (US-ASCII decimal 78), that is "\n" or "\N".
+ *
+ * The "TEXT" property values may also contain special characters that
+ * are used to signify delimiters, such as a COMMA character for lists
+ * of values or a SEMICOLON character for structured values. In order to
+ * support the inclusion of these special characters in "TEXT" property
+ * values, they MUST be escaped with a BACKSLASH character. A BACKSLASH
+ * character (US-ASCII decimal 92) in a "TEXT" property value MUST be
+ * escaped with another BACKSLASH character. A COMMA character in a
+ * "TEXT" property value MUST be escaped with a BACKSLASH character
+ * (US-ASCII decimal 92). A SEMICOLON character in a "TEXT" property
+ * value MUST be escaped with a BACKSLASH character (US-ASCII decimal
+ * 92). However, a COLON character in a "TEXT" property value SHALL NOT
+ * be escaped with a BACKSLASH character.Example: A multiple line value
+ * of:
+ *
+ * Project XYZ Final Review
+ * Conference Room - 3B
+ * Come Prepared.
+ *
+ * would be represented as:
+ *
+ * Project XYZ Final Review\nConference Room - 3B\nCome Prepared.
+ *
+ */
+public final class Strings {
+
+ /**
+ * Defines a regular expression representing all parameter strings that
+ * should be quoted.
+ */
+ public static final Pattern PARAM_QUOTE_PATTERN = Pattern.compile("[:;,]|[^\\p{ASCII}]");
+
+ private static final Pattern ESCAPE_PUNCTUATION_PATTERN = Pattern.compile("([,;])");
+ private static final Pattern UNESCAPE_PUNCTUATION_PATTERN = Pattern.compile("\\\\([,;\"])");
+
+ private static final Pattern ESCAPE_NEWLINE_PATTERN = Pattern.compile("\r?\n");
+ private static final Pattern UNESCAPE_NEWLINE_PATTERN = Pattern.compile("(?toString() method.
+ * @param aValue an object to quote
+ * @return a quoted string
+ */
+ public static String quote(final Object aValue) {
+ if (aValue != null) {
+ return "\"" + aValue + "\"";
+ }
+ return "\"\"";
+ }
+
+ /**
+ * Convenience method for removing surrounding quotes
+ * from a string value.
+ * @param aValue a string to remove quotes from
+ * @return an un-quoted string
+ */
+ public static String unquote(final String aValue) {
+ if (aValue != null && aValue.startsWith("\"") && aValue.endsWith("\"")) {
+ return aValue.substring(0, aValue.length() - 1).substring(1);
+ }
+ return aValue;
+ }
+
+ /**
+ * Convenience method for escaping special characters.
+ * @param aValue a string value to escape
+ * @return an escaped representation of the specified
+ * string
+ */
+ public static String escape(final String aValue) {
+ return escapePunctuation(escapeNewline(escapeBackslash(aValue)));
+ }
+
+ /**
+ * Convenience method for replacing escaped special characters
+ * with their original form.
+ * @param aValue a string value to unescape
+ * @return a string representation of the specified
+ * string with escaped characters replaced with their
+ * original form
+ */
+ public static String unescape(final String aValue) {
+ return unescapeBackslash(unescapeNewline(unescapePunctuation(aValue)));
+ }
+
+ private static String escapePunctuation(String value) {
+ if (value != null) {
+ return ESCAPE_PUNCTUATION_PATTERN.matcher(value).replaceAll("\\\\$1");
+ }
+ return value;
+ }
+
+ private static String unescapePunctuation(String value) {
+ if (value != null) {
+ return UNESCAPE_PUNCTUATION_PATTERN.matcher(value).replaceAll("$1");
+ }
+ return value;
+ }
+
+ public static String escapeNewline(String value) {
+ if (value != null) {
+ return ESCAPE_NEWLINE_PATTERN.matcher(value).replaceAll("\\\\n");
+ }
+ return value;
+ }
+
+ private static String unescapeNewline(String value) {
+ if (value != null) {
+ return UNESCAPE_NEWLINE_PATTERN.matcher(value).replaceAll("\n");
+ }
+ return value;
+ }
+
+ private static String escapeBackslash(String value) {
+ if (value != null) {
+ return ESCAPE_BACKSLASH_PATTERN.matcher(value).replaceAll("\\\\\\\\");
+ }
+ return value;
+ }
+
+ private static String unescapeBackslash(String value) {
+ if (value != null) {
+ return UNESCAPE_BACKSLASH_PATTERN.matcher(value).replaceAll("\\\\");
+ }
+ return value;
+ }
+
+ /**
+ * Wraps java.lang.String.valueOf() to return an empty string
+ * where the specified object is null.
+ * @param object an object instance
+ * @return a string representation of the object
+ */
+ public static String valueOf(final Object object) {
+ if (object == null) {
+ return "";
+ }
+ return object.toString();
+ }
+}