1 /*
2 Copyright 2008 Ramon Servadei
3
4 Licensed under the Apache License, Version 2.0 (the "License");
5 you may not use this file except in compliance with the License.
6 You may obtain a copy of the License at
7
8 http://www.apache.org/licenses/LICENSE-2.0
9
10 Unless required by applicable law or agreed to in writing, software
11 distributed under the License is distributed on an "AS IS" BASIS,
12 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 See the License for the specific language governing permissions and
14 limitations under the License.
15 */
16 package fulmine.util.collection;
17
18 import static fulmine.util.Utils.CLOSE_CURLY;
19 import static fulmine.util.Utils.OPEN_CURLY;
20 import static fulmine.util.Utils.SPACING_4_CHARS;
21 import static fulmine.util.Utils.safeToString;
22
23 import java.util.Collection;
24 import java.util.Map;
25 import java.util.Set;
26
27 import org.apache.commons.lang.SystemUtils;
28
29 /**
30 * Useful utility methods for {@link Collection} instances.
31 *
32 * @author Ramon Servadei
33 *
34 */
35 public abstract class CollectionUtils
36 {
37 /**
38 * Used for indentation of the {@link #toFormattedString(Collection)} method
39 */
40 private final static ThreadLocal<Integer> indent =
41 new ThreadLocal<Integer>();
42
43 /**
44 * Get a formatted string for the collection. Each element is printed on a
45 * new line.
46 *
47 * @param collection
48 * the collection to produce the formatted string for
49 * @return a {@link StringBuilder} with each element of the collection
50 * printed on a new line.
51 */
52 @SuppressWarnings("unchecked")
53 public static StringBuilder toFormattedString(Collection collection)
54 {
55 try
56 {
57 String indent = indent();
58 StringBuilder sb = new StringBuilder();
59 sb.append(SystemUtils.LINE_SEPARATOR).append(indent).append(
60 OPEN_CURLY);
61 for (Object element : collection)
62 {
63 sb.append(SystemUtils.LINE_SEPARATOR).append(indent).append(
64 SPACING_4_CHARS).append(safeToString(element));
65 }
66 sb.append(SystemUtils.LINE_SEPARATOR).append(indent).append(
67 CLOSE_CURLY);
68 return sb;
69 }
70 catch (RuntimeException e)
71 {
72 indent.remove();
73 throw e;
74 }
75 finally
76 {
77 unindent();
78 }
79 }
80
81 /**
82 * Using the {@link #indent} thread local, increment this by 1 and return an
83 * indenting string representing this indentation level
84 *
85 * @return an indenting string representing the current indentation level
86 */
87 @SuppressWarnings("boxing")
88 private static String indent()
89 {
90 Integer level = indent.get();
91 if (level == null)
92 {
93 level = Integer.valueOf(-1);
94 }
95 indent.set(++level);
96 StringBuilder sb = new StringBuilder();
97 for (int i = 0; i < level; i++)
98 {
99 sb.append(SPACING_4_CHARS);
100 }
101 return sb.toString();
102 }
103
104 /**
105 * Decrement the current thread local indentation level
106 */
107 @SuppressWarnings("boxing")
108 private static void unindent()
109 {
110 Integer level = indent.get();
111 if (level != null)
112 {
113 indent.set(--level);
114 }
115 }
116
117 /**
118 * Get a formatted string for the map. Each map entry is printed on a new
119 * line.
120 *
121 * @param map
122 * the map to produce the formatted string for
123 * @return a {@link StringBuilder} with each map entry of the collection
124 * printed on a new line.
125 */
126 @SuppressWarnings("unchecked")
127 public static StringBuilder toFormattedString(Map map)
128 {
129 StringBuilder sb = new StringBuilder();
130 final Set entrySet = map.entrySet();
131 return sb.append(toFormattedString(entrySet));
132 }
133 }