| KeyUtil.java |
1 /**
2 * Distribution License:
3 * JSword is free software; you can redistribute it and/or modify it under
4 * the terms of the GNU Lesser General Public License, version 2.1 or later
5 * as published by the Free Software Foundation. This program is distributed
6 * in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
7 * the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
8 * See the GNU Lesser General Public License for more details.
9 *
10 * The License is available on the internet at:
11 * http://www.gnu.org/copyleft/lgpl.html
12 * or by writing to:
13 * Free Software Foundation, Inc.
14 * 59 Temple Place - Suite 330
15 * Boston, MA 02111-1307, USA
16 *
17 * © CrossWire Bible Society, 2005 - 2016
18 *
19 */
20 package org.crosswire.jsword.passage;
21
22 import org.crosswire.jsword.versification.Versification;
23 import org.crosswire.jsword.versification.system.Versifications;
24
25 /**
26 * .
27 *
28 * @see gnu.lgpl.License The GNU Lesser General Public License for details.
29 * @author Joe Walker
30 * @author DM Smith
31 */
32 public final class KeyUtil {
33 /**
34 * Prevent instantiation
35 */
36 private KeyUtil() {
37 }
38
39 /**
40 * Walk through a tree visiting the nodes and branches in the tree
41 *
42 * @param key
43 * The node tree to walk through
44 * @param visitor
45 * The visitor to notify whenever a node is found
46 */
47 public static void visit(Key key, KeyVisitor visitor) {
48 for (Key subkey : key) {
49 if (subkey.canHaveChildren()) {
50 visitor.visitBranch(subkey);
51 visit(subkey, visitor);
52 } else {
53 visitor.visitLeaf(subkey);
54 }
55 }
56 }
57
58 /**
59 * Cast a Key to a Verse. Only those keys that are a Verse or can
60 * contain Verses (i.e. Passage and VerseRange) may be cast to one.
61 * Verse containers (i.e. Passage and VerseRange) return their
62 * first verse.
63 *
64 * @param key The key to cast
65 * @return The key cast to a Verse
66 * @throws ClassCastException
67 */
68 public static Verse getVerse(Key key) {
69 if (key instanceof Verse) {
70 return (Verse) key;
71 }
72
73 if (key instanceof VerseRange) {
74 VerseRange range = (VerseRange) key;
75 return range.getStart();
76 }
77
78 if (key instanceof Passage) {
79 Passage ref = (Passage) key;
80 return ref.getVerseAt(0);
81 }
82
83 throw new ClassCastException("Expected key to be a Verse, VerseRange or Passage");
84 }
85
86 /**
87 * Cast a Key to a Passage. Only those keys that are a Passage or can
88 * be held by a Passage (i.e. Verse and VerseRange) may be cast to one.
89 * If you pass a null key into this method, you get a null Passage out.
90 *
91 * @param key The key to cast
92 * @return The key cast to a Passage
93 * @throws ClassCastException
94 */
95 public static Passage getPassage(Key key) {
96 if (key == null) {
97 return null;
98 }
99
100 if (key instanceof Passage) {
101 return (Passage) key;
102 }
103
104 if (key instanceof VerseKey) {
105 VerseKey verseKey = (VerseKey) key;
106 Key ref = PassageKeyFactory.instance().createEmptyKeyList(verseKey.getVersification());
107 ref.addAll(verseKey);
108 return (Passage) ref;
109 }
110
111 throw new ClassCastException("Expected key to be a Verse, VerseRange or Passage");
112 }
113
114 /**
115 * Get the versification for the key or the default versification.
116 *
117 * @param key the key that should provide for the Versification
118 * @return the versification for the key
119 */
120 public static Versification getVersification(Key key) {
121 if (key instanceof VerseKey) {
122 return ((VerseKey) key).getVersification();
123 }
124 return Versifications.instance().getVersification(Versifications.DEFAULT_V11N);
125 }
126 }
127