Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
HierarchicalConfigurationConverter |
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| 2.2857142857142856;2,286 |
1 | /* | |
2 | * Licensed to the Apache Software Foundation (ASF) under one or more | |
3 | * contributor license agreements. See the NOTICE file distributed with | |
4 | * this work for additional information regarding copyright ownership. | |
5 | * The ASF licenses this file to You under the Apache License, Version 2.0 | |
6 | * (the "License"); you may not use this file except in compliance with | |
7 | * the License. You may obtain a copy of the License at | |
8 | * | |
9 | * http://www.apache.org/licenses/LICENSE-2.0 | |
10 | * | |
11 | * Unless required by applicable law or agreed to in writing, software | |
12 | * distributed under the License is distributed on an "AS IS" BASIS, | |
13 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
14 | * See the License for the specific language governing permissions and | |
15 | * limitations under the License. | |
16 | */ | |
17 | ||
18 | package org.apache.commons.configuration; | |
19 | ||
20 | import java.util.ArrayList; | |
21 | import java.util.Collection; | |
22 | import java.util.Collections; | |
23 | import java.util.HashSet; | |
24 | import java.util.Iterator; | |
25 | import java.util.List; | |
26 | import java.util.Set; | |
27 | ||
28 | /** | |
29 | * <p>A base class for converters that transform a normal configuration | |
30 | * object into a hierarchical configuration.</p> | |
31 | * <p>This class provides a default mechanism for iterating over the keys in a | |
32 | * configuration and to throw corresponding element start and end events. By | |
33 | * handling these events a hierarchy can be constructed that is equivalent to | |
34 | * the keys in the original configuration.</p> | |
35 | * <p>Concrete sub classes will implement event handlers that generate SAX | |
36 | * events for XML processing or construct a | |
37 | * <code>HierarchicalConfiguration</code> root node. All in all with this class | |
38 | * it is possible to treat a default configuration as if it was a hierarchical | |
39 | * configuration, which can be sometimes useful.</p> | |
40 | * @see HierarchicalConfiguration | |
41 | * | |
42 | * @author <a href="mailto:oliver.heger@t-online.de">Oliver Heger</a> | |
43 | * @version $Id: HierarchicalConfigurationConverter.java 439648 2006-09-02 20:42:10Z oheger $ | |
44 | */ | |
45 | 3 | abstract class HierarchicalConfigurationConverter |
46 | { | |
47 | /** | |
48 | * Processes the specified configuration object. This method implements | |
49 | * the iteration over the configuration's keys. All defined keys are | |
50 | * translated into a set of element start and end events represented by | |
51 | * calls to the <code>elementStart()</code> and | |
52 | * <code>elementEnd()</code> methods. | |
53 | * | |
54 | * @param config the configuration to be processed | |
55 | */ | |
56 | public void process(Configuration config) | |
57 | { | |
58 | 3 | if (config != null) |
59 | { | |
60 | 3 | ConfigurationKey keyEmpty = new ConfigurationKey(); |
61 | 3 | ConfigurationKey keyLast = keyEmpty; |
62 | 3 | Set keySet = new HashSet(); |
63 | ||
64 | 36 | for (Iterator it = config.getKeys(); it.hasNext();) |
65 | { | |
66 | 30 | String key = (String) it.next(); |
67 | 30 | if (keySet.contains(key)) |
68 | { | |
69 | // this key has already been processed by openElements | |
70 | 0 | continue; |
71 | } | |
72 | 30 | ConfigurationKey keyAct = new ConfigurationKey(key); |
73 | 30 | closeElements(keyLast, keyAct); |
74 | 30 | String elem = openElements(keyLast, keyAct, config, keySet); |
75 | 30 | fireValue(elem, config.getProperty(key)); |
76 | 30 | keyLast = keyAct; |
77 | } | |
78 | ||
79 | // close all open | |
80 | 3 | closeElements(keyLast, keyEmpty); |
81 | } | |
82 | 3 | } |
83 | ||
84 | /** | |
85 | * An event handler method that is called when an element starts. | |
86 | * Concrete sub classes must implement it to perform a proper event | |
87 | * handling. | |
88 | * | |
89 | * @param name the name of the new element | |
90 | * @param value the element's value; can be <b>null</b> if the element | |
91 | * does not have any value | |
92 | */ | |
93 | protected abstract void elementStart(String name, Object value); | |
94 | ||
95 | /** | |
96 | * An event handler method that is called when an element ends. For each | |
97 | * call of <code>elementStart()</code> there will be a corresponding call | |
98 | * of this method. Concrete sub classes must implement it to perform a | |
99 | * proper event handling. | |
100 | * | |
101 | * @param name the name of the ending element | |
102 | */ | |
103 | protected abstract void elementEnd(String name); | |
104 | ||
105 | /** | |
106 | * Fires all necessary element end events for the specified keys. This | |
107 | * method is called for each key obtained from the configuration to be | |
108 | * converted. It calculates the common part of the actual and the last | |
109 | * processed key and thus determines how many elements must be | |
110 | * closed. | |
111 | * | |
112 | * @param keyLast the last processed key | |
113 | * @param keyAct the actual key | |
114 | */ | |
115 | protected void closeElements(ConfigurationKey keyLast, ConfigurationKey keyAct) | |
116 | { | |
117 | 33 | ConfigurationKey keyDiff = keyAct.differenceKey(keyLast); |
118 | 33 | Iterator it = reverseIterator(keyDiff); |
119 | 33 | if (it.hasNext()) |
120 | { | |
121 | // Skip first because it has already been closed by fireValue() | |
122 | 30 | it.next(); |
123 | } | |
124 | ||
125 | 48 | while (it.hasNext()) |
126 | { | |
127 | 15 | elementEnd((String) it.next()); |
128 | } | |
129 | 33 | } |
130 | ||
131 | /** | |
132 | * Helper method for determining a reverse iterator for the specified key. | |
133 | * This implementation returns an iterator that returns the parts of the | |
134 | * given key in reverse order, ignoring indices. | |
135 | * | |
136 | * @param key the key | |
137 | * @return a reverse iterator for the parts of this key | |
138 | */ | |
139 | protected Iterator reverseIterator(ConfigurationKey key) | |
140 | { | |
141 | 33 | List list = new ArrayList(); |
142 | 111 | for (ConfigurationKey.KeyIterator it = key.iterator(); it.hasNext();) |
143 | { | |
144 | 45 | list.add(it.nextKey()); |
145 | } | |
146 | ||
147 | 33 | Collections.reverse(list); |
148 | 33 | return list.iterator(); |
149 | } | |
150 | ||
151 | /** | |
152 | * Fires all necessary element start events for the specified key. This | |
153 | * method is called for each key obtained from the configuration to be | |
154 | * converted. It ensures that all elements "between" the last key and the | |
155 | * actual key are opened and their values are set. | |
156 | * | |
157 | * @param keyLast the last processed key | |
158 | * @param keyAct the actual key | |
159 | * @param config the configuration to process | |
160 | * @param keySet the set with the processed keys | |
161 | * @return the name of the last element on the path | |
162 | */ | |
163 | protected String openElements(ConfigurationKey keyLast, ConfigurationKey keyAct, Configuration config, Set keySet) | |
164 | { | |
165 | 30 | ConfigurationKey.KeyIterator it = keyLast.differenceKey(keyAct).iterator(); |
166 | 30 | ConfigurationKey k = keyLast.commonKey(keyAct); |
167 | 45 | for (it.nextKey(); it.hasNext(); it.nextKey()) |
168 | { | |
169 | 15 | k.append(it.currentKey(true)); |
170 | 15 | elementStart(it.currentKey(true), config.getProperty(k.toString())); |
171 | 15 | keySet.add(k.toString()); |
172 | } | |
173 | 30 | return it.currentKey(true); |
174 | } | |
175 | ||
176 | /** | |
177 | * Fires all necessary element start events with the actual element values. | |
178 | * This method is called for each key obtained from the configuration to be | |
179 | * processed with the last part of the key as argument. The value can be | |
180 | * either a single value or a collection. | |
181 | * | |
182 | * @param name the name of the actual element | |
183 | * @param value the element's value | |
184 | */ | |
185 | protected void fireValue(String name, Object value) | |
186 | { | |
187 | 51 | if (value != null && value instanceof Collection) |
188 | { | |
189 | 33 | for (Iterator it = ((Collection) value).iterator(); it.hasNext();) |
190 | { | |
191 | 21 | fireValue(name, it.next()); |
192 | } | |
193 | } | |
194 | else | |
195 | { | |
196 | 45 | elementStart(name, value); |
197 | 45 | elementEnd(name); |
198 | } | |
199 | 51 | } |
200 | } |