001 package biweekly.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
031 /**
032 * Contains miscellaneous string utilities.
033 * @author Michael Angstadt
034 */
035 public class StringUtils {
036 /**
037 * The local computer's newline character sequence.
038 */
039 public static final String NEWLINE = System.getProperty("line.separator");
040
041 /**
042 * Joins a collection of values into a delimited list.
043 * @param collection the collection of values
044 * @param delimiter the delimiter (e.g. ",")
045 * @return the final string
046 */
047 public static <T> String join(Collection<T> collection, String delimiter) {
048 StringBuilder sb = new StringBuilder();
049 join(collection, delimiter, sb);
050 return sb.toString();
051 }
052
053 /**
054 * Joins a collection of values into a delimited list.
055 * @param collection the collection of values
056 * @param delimiter the delimiter (e.g. ",")
057 * @param sb the string builder to append onto
058 */
059 public static <T> void join(Collection<T> collection, String delimiter, StringBuilder sb) {
060 join(collection, delimiter, sb, new JoinCallback<T>() {
061 public void handle(StringBuilder sb, T value) {
062 sb.append(value);
063 }
064 });
065 }
066
067 /**
068 * Joins a collection of values into a delimited list.
069 * @param collection the collection of values
070 * @param delimiter the delimiter (e.g. ",")
071 * @param join callback function to call on every element in the collection
072 * @return the final string
073 */
074 public static <T> String join(Collection<T> collection, String delimiter, JoinCallback<T> join) {
075 StringBuilder sb = new StringBuilder();
076 join(collection, delimiter, sb, join);
077 return sb.toString();
078 }
079
080 /**
081 * Joins a collection of values into a delimited list.
082 * @param collection the collection of values
083 * @param delimiter the delimiter (e.g. ",")
084 * @param sb the string builder to append onto
085 * @param join callback function to call on every element in the collection
086 */
087 public static <T> void join(Collection<T> collection, String delimiter, StringBuilder sb, JoinCallback<T> join) {
088 boolean first = true;
089 for (T element : collection) {
090 if (first) {
091 first = false;
092 } else {
093 sb.append(delimiter);
094 }
095 join.handle(sb, element);
096 }
097 }
098
099 /**
100 * Joins a map into a delimited list.
101 * @param map the map
102 * @param delimiter the delimiter (e.g. ",")
103 * @param join callback function to call on every element in the collection
104 * @return the final string
105 */
106 public static <K, V> String join(Map<K, V> map, String delimiter, final JoinMapCallback<K, V> join) {
107 return join(map.entrySet(), delimiter, new JoinCallback<Map.Entry<K, V>>() {
108 public void handle(StringBuilder sb, Map.Entry<K, V> entry) {
109 join.handle(sb, entry.getKey(), entry.getValue());
110 }
111 });
112 }
113
114 /**
115 * Callback interface used with the
116 * {@link StringUtils#join(Collection, String, JoinCallback)} method.
117 * @author Michael Angstadt
118 * @param <T> the value type
119 */
120 public static interface JoinCallback<T> {
121 void handle(StringBuilder sb, T value);
122 }
123
124 /**
125 * Callback interface used with the
126 * {@link StringUtils#join(Map, String, JoinMapCallback)} method.
127 * @author Michael Angstadt
128 * @param <K> the key class
129 * @param <V> the value class
130 */
131 public static interface JoinMapCallback<K, V> {
132 void handle(StringBuilder sb, K key, V value);
133 }
134
135 private StringUtils() {
136 //hide
137 }
138 }