001 package ezvcard.util;
002
003 import java.util.Collection;
004 import java.util.Map;
005
006 /*
007 Copyright (c) 2013, Michael Angstadt
008 All rights reserved.
009
010 Redistribution and use in source and binary forms, with or without
011 modification, are permitted provided that the following conditions are met:
012
013 1. Redistributions of source code must retain the above copyright notice, this
014 list of conditions and the following disclaimer.
015 2. Redistributions in binary form must reproduce the above copyright notice,
016 this list of conditions and the following disclaimer in the documentation
017 and/or other materials provided with the distribution.
018
019 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
020 ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
021 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
022 DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
023 ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
024 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
025 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
026 ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
027 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
028 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
029
030 The views and conclusions contained in the software and documentation are those
031 of the authors and should not be interpreted as representing official policies,
032 either expressed or implied, of the FreeBSD Project.
033 */
034
035 /**
036 * Helper class for dealing with vCard strings.
037 * @author Michael Angstadt
038 */
039 public class StringUtils {
040 /**
041 * The local computer's newline character sequence.
042 */
043 public static final String NEWLINE = System.getProperty("line.separator");
044
045 /**
046 * Trims the whitespace off the left side of a string.
047 * @param string the string to trim
048 * @return the trimmed string
049 */
050 public static String ltrim(String string) {
051 if (string == null) {
052 return null;
053 }
054
055 int i;
056 for (i = 0; i < string.length() && Character.isWhitespace(string.charAt(i)); i++) {
057 //do nothing
058 }
059 return (i == string.length()) ? "" : string.substring(i);
060 }
061
062 /**
063 * Trims the whitespace off the right side of a string.
064 * @param string the string to trim
065 * @return the trimmed string
066 */
067 public static String rtrim(String string) {
068 if (string == null) {
069 return null;
070 }
071
072 int i;
073 for (i = string.length() - 1; i >= 0 && Character.isWhitespace(string.charAt(i)); i--) {
074 //do nothing
075 }
076 return (i == 0) ? "" : string.substring(0, i + 1);
077 }
078
079 /**
080 * Joins a collection of values into a delimited list.
081 * @param collection the collection of values
082 * @param delimiter the delimiter (e.g. ",")
083 * @return the final string
084 */
085 public static <T> String join(Collection<T> collection, String delimiter) {
086 StringBuilder sb = new StringBuilder();
087 join(collection, delimiter, sb);
088 return sb.toString();
089 }
090
091 /**
092 * Joins a collection of values into a delimited list.
093 * @param collection the collection of values
094 * @param delimiter the delimiter (e.g. ",")
095 * @param sb the string builder to append onto
096 */
097 public static <T> void join(Collection<T> collection, String delimiter, StringBuilder sb) {
098 join(collection, delimiter, sb, new JoinCallback<T>() {
099 public void handle(StringBuilder sb, T value) {
100 sb.append(value);
101 }
102 });
103 }
104
105 /**
106 * Joins a collection of values into a delimited list.
107 * @param collection the collection of values
108 * @param delimiter the delimiter (e.g. ",")
109 * @param join callback function to call on every element in the collection
110 * @return the final string
111 */
112 public static <T> String join(Collection<T> collection, String delimiter, JoinCallback<T> join) {
113 StringBuilder sb = new StringBuilder();
114 join(collection, delimiter, sb, join);
115 return sb.toString();
116 }
117
118 /**
119 * Joins a collection of values into a delimited list.
120 * @param collection the collection of values
121 * @param delimiter the delimiter (e.g. ",")
122 * @param sb the string builder to append onto
123 * @param join callback function to call on every element in the collection
124 */
125 public static <T> void join(Collection<T> collection, String delimiter, StringBuilder sb, JoinCallback<T> join) {
126 boolean first = true;
127 for (T element : collection) {
128 if (first) {
129 first = false;
130 } else {
131 sb.append(delimiter);
132 }
133 join.handle(sb, element);
134 }
135 }
136
137 /**
138 * Joins a map into a delimited list.
139 * @param map the map
140 * @param delimiter the delimiter (e.g. ",")
141 * @param join callback function to call on every element in the collection
142 * @return the final string
143 */
144 public static <K, V> String join(Map<K, V> map, String delimiter, final JoinMapCallback<K, V> join) {
145 return join(map.entrySet(), delimiter, new JoinCallback<Map.Entry<K, V>>() {
146 public void handle(StringBuilder sb, Map.Entry<K, V> entry) {
147 join.handle(sb, entry.getKey(), entry.getValue());
148 }
149 });
150 }
151
152 /**
153 * Callback interface used with various {@code VCardStringUtils.join()}
154 * methods.
155 * @author Michael Angstadt
156 * @param <T> the value type
157 */
158 public static interface JoinCallback<T> {
159 void handle(StringBuilder sb, T value);
160 }
161
162 /**
163 * Callback interface used with the
164 * {@link #join(Map, String, JoinMapCallback)} method.
165 * @author Michael Angstadt
166 * @param <K> the key class
167 * @param <V> the value class
168 */
169 public static interface JoinMapCallback<K, V> {
170 void handle(StringBuilder sb, K key, V value);
171 }
172
173 private StringUtils() {
174 //hide constructor
175 }
176 }