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Source file | Conditionals | Statements | Methods | TOTAL | |||||||||||||||
DefaultPrimaryKeyConverter.java | 86.4% | 98.1% | 100% | 95.7% |
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1 | // Copyright 2005 The Apache Software Foundation | |
2 | // | |
3 | // Licensed under the Apache License, Version 2.0 (the "License"); | |
4 | // you may not use this file except in compliance with the License. | |
5 | // You may obtain a copy of the License at | |
6 | // | |
7 | // http://www.apache.org/licenses/LICENSE-2.0 | |
8 | // | |
9 | // Unless required by applicable law or agreed to in writing, software | |
10 | // distributed under the License is distributed on an "AS IS" BASIS, | |
11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
12 | // See the License for the specific language governing permissions and | |
13 | // limitations under the License. | |
14 | ||
15 | package org.apache.tapestry.util; | |
16 | ||
17 | import java.util.ArrayList; | |
18 | import java.util.Collections; | |
19 | import java.util.HashMap; | |
20 | import java.util.HashSet; | |
21 | import java.util.List; | |
22 | import java.util.Map; | |
23 | import java.util.Set; | |
24 | ||
25 | import org.apache.hivemind.ApplicationRuntimeException; | |
26 | import org.apache.hivemind.util.Defense; | |
27 | import org.apache.tapestry.components.IPrimaryKeyConverter; | |
28 | ||
29 | /** | |
30 | * Companion to the {@link org.apache.tapestry.components.ForBean For component}, this class is an | |
31 | * implementation of {@link org.apache.tapestry.components.IPrimaryKeyConverter} that performs some | |
32 | * additional handling, such as tracking value sets.. | |
33 | * <p> | |
34 | * Value sets are sets of value objects maintained by the converter; the converter will provide a | |
35 | * synthetic read/write boolean property that indicates if the {@link #getLastValue() last value} is | |
36 | * or is not in the set. | |
37 | * <p> | |
38 | * A single built-in value set, {@link #isDeleted()} has a special purpose; it controls whether or | |
39 | * not values are returned from {@link #getValues()}. Subclasses may add additional synthetic | |
40 | * boolean properties and additional sets. | |
41 | * <p> | |
42 | * Why not just store a boolean property in the object itself? Well, deleted is a good example of a | |
43 | * property that is meaningful in the context of an operation, but isn't stored ... once an object | |
44 | * is deleted (from secondary storage, such as a database) there's no place to store such a flag. | |
45 | * The DefaultPrimaryKey converter is used in this context to store transient, operation data ... | |
46 | * such as which values are to be deleted. | |
47 | * <p> | |
48 | * This class can be thought of as a successor to {@link org.apache.tapestry.form.ListEditMap}. | |
49 | * | |
50 | * @author Howard M. Lewis Ship | |
51 | * @since 4.0 | |
52 | */ | |
53 | public class DefaultPrimaryKeyConverter implements IPrimaryKeyConverter | |
54 | { | |
55 | private final Map _map = new HashMap(); | |
56 | ||
57 | private final List _keys = new ArrayList(); | |
58 | ||
59 | // The values added to the Map, in the order they were added. | |
60 | private final List _values = new ArrayList(); | |
61 | ||
62 | // The last value accessed by getPrimaryKey() or getValue(). | |
63 | // Other methods may operate upon this value. | |
64 | ||
65 | private Object _lastValue; | |
66 | ||
67 | private Set _deletedValues; | |
68 | ||
69 | /** | |
70 | * Clears all properties of the converter, returning it to a pristine state. Subclasses should | |
71 | * invoke this implementation in addition to clearing any of their own state. | |
72 | */ | |
73 | 1 | public void clear() |
74 | { | |
75 | 1 | _map.clear(); |
76 | 1 | _keys.clear(); |
77 | 1 | _values.clear(); |
78 | 1 | _lastValue = null; |
79 | 1 | _deletedValues = null; |
80 | } | |
81 | ||
82 | 17 | public final void add(Object key, Object value) |
83 | { | |
84 | 17 | Defense.notNull(key, "key"); |
85 | 17 | Defense.notNull(value, "value"); |
86 | ||
87 | 17 | if (_map.containsKey(key)) |
88 | 1 | throw new ApplicationRuntimeException(UtilMessages.keyAlreadyExists(key)); |
89 | ||
90 | 16 | _map.put(key, value); |
91 | ||
92 | 16 | _keys.add(key); |
93 | 16 | _values.add(value); |
94 | ||
95 | 16 | _lastValue = value; |
96 | } | |
97 | ||
98 | /** | |
99 | * Returns a unmodifiable list of values stored into the converter, in the order in which they | |
100 | * were stored. | |
101 | * | |
102 | * @return an unmodifiable List | |
103 | * @see #add(Object, Object) | |
104 | */ | |
105 | 8 | public final List getAllValues() |
106 | { | |
107 | 8 | return Collections.unmodifiableList(_values); |
108 | } | |
109 | ||
110 | /** | |
111 | * Returns a list of all values stored into the converter, with deleted values removed. | |
112 | */ | |
113 | ||
114 | 7 | public final List getValues() |
115 | { | |
116 | 7 | if (isDeletedValuesEmpty()) |
117 | 4 | return getAllValues(); |
118 | ||
119 | 3 | List result = new ArrayList(_values); |
120 | ||
121 | 3 | result.removeAll(_deletedValues); |
122 | ||
123 | 3 | return result; |
124 | } | |
125 | ||
126 | /** | |
127 | * Returns true if the deleted values set is empty (or null).l | |
128 | */ | |
129 | 8 | private boolean isDeletedValuesEmpty() |
130 | { | |
131 | 8 | return _deletedValues == null || _deletedValues.isEmpty(); |
132 | } | |
133 | ||
134 | /** | |
135 | * Checks to see if the {@link #getLastValue() last value} is, or is not, in the set of deleted | |
136 | * values. | |
137 | */ | |
138 | 3 | public final boolean isDeleted() |
139 | { | |
140 | 3 | return checkValueSetForLastValue(_deletedValues); |
141 | } | |
142 | ||
143 | /** | |
144 | * Checks the set to see if it contains the {@link #getLastValue() last value}. | |
145 | * | |
146 | * @param valueSet | |
147 | * the set to check, which may be null | |
148 | * @return true if the last value is in the set (if non-null) | |
149 | */ | |
150 | 3 | protected final boolean checkValueSetForLastValue(Set valueSet) |
151 | { | |
152 | 3 | return valueSet != null && valueSet.contains(_lastValue); |
153 | } | |
154 | ||
155 | /** | |
156 | * Adds or removes the {@link #getLastValue() last value} from the | |
157 | * {@link #getDeletedValues() deleted values set}. | |
158 | * | |
159 | * @param deleted | |
160 | */ | |
161 | 5 | public final void setDeleted(boolean deleted) |
162 | { | |
163 | 5 | _deletedValues = updateValueSetForLastValue(_deletedValues, deleted); |
164 | } | |
165 | ||
166 | /** | |
167 | * Updates a value set to add or remove the {@link #getLastValue() last value} to the set. The | |
168 | * logic here will create and return a new Set instance if necessary (that is, if inSet is true | |
169 | * and set is null). The point is to defer the creation of the set until its actually needed. | |
170 | * | |
171 | * @param set | |
172 | * the set to update, which may be null | |
173 | * @param inSet | |
174 | * if true, the last value will be added to the set (creating the set as necessary); | |
175 | * if false, the last value will be removed | |
176 | * @return the set passed in, or a new Set instance | |
177 | */ | |
178 | 5 | protected final Set updateValueSetForLastValue(Set set, boolean inSet) |
179 | { | |
180 | 5 | if (inSet) |
181 | { | |
182 | 4 | if (set == null) |
183 | 4 | set = new HashSet(); |
184 | ||
185 | 4 | set.add(_lastValue); |
186 | ||
187 | 4 | return set; |
188 | } | |
189 | ||
190 | 1 | if (set != null) |
191 | 1 | set.remove(_lastValue); |
192 | ||
193 | 1 | return set; |
194 | } | |
195 | ||
196 | /** | |
197 | * Returns the last active value; this is the value passed to {@link #getPrimaryKey(Object)} or | |
198 | * the value for the key passed to {@link #getValue(Object)}. | |
199 | * <p> | |
200 | * Maintaining <em>value sets</em> involves adding or removing the active value from a set. | |
201 | * | |
202 | * @return the last active object | |
203 | */ | |
204 | 9 | public final Object getLastValue() |
205 | { | |
206 | 9 | return _lastValue; |
207 | } | |
208 | ||
209 | /** | |
210 | * Returns an unmodifiable set of all values marked as deleted. | |
211 | */ | |
212 | ||
213 | 6 | public final Set getDeletedValues() |
214 | { | |
215 | 6 | return createUnmodifiableSet(_deletedValues); |
216 | } | |
217 | ||
218 | /** | |
219 | * Converts a value set into a returnable value; null is converted to the empty set, and | |
220 | * non-null is wrapped as unmodifiable. | |
221 | * | |
222 | * @param valueSet | |
223 | * the set to convert and return | |
224 | * @return a non-null, non-modifiable Set | |
225 | */ | |
226 | 6 | protected final Set createUnmodifiableSet(Set valueSet) |
227 | { | |
228 | 6 | return valueSet == null ? Collections.emptySet() : Collections.unmodifiableSet(valueSet); |
229 | } | |
230 | ||
231 | /** | |
232 | * Iterates over the keys and values, removing any values (and corresponding keys) that that are | |
233 | * in the deleted set. After invoking this, {@link #getAllValues()} will be the same as | |
234 | * {@link #getValues()}. | |
235 | */ | |
236 | 1 | public final void removeDeletedValues() |
237 | { | |
238 | 1 | _lastValue = null; |
239 | ||
240 | 1 | if (isDeletedValuesEmpty()) |
241 | 0 | return; |
242 | ||
243 | 1 | int count = _keys.size(); |
244 | ||
245 | 1 | for (int i = count - 1; i >= 0; i--) |
246 | { | |
247 | 2 | if (_deletedValues.contains(_values.get(i))) |
248 | { | |
249 | 1 | _values.remove(i); |
250 | 1 | Object key = _keys.remove(i); |
251 | ||
252 | 1 | _map.remove(key); |
253 | } | |
254 | } | |
255 | } | |
256 | ||
257 | /** | |
258 | * Gets the primary key of an object previously stored in this converter. | |
259 | * | |
260 | * @param value | |
261 | * an object previously stored in the converter | |
262 | * @return the corresponding key used to store the object | |
263 | * @throws ApplicationRuntimeException | |
264 | * if the value was not previously stored | |
265 | * @see #add(Object, Object) | |
266 | */ | |
267 | 4 | public final Object getPrimaryKey(Object value) |
268 | { | |
269 | 4 | int index = _values.indexOf(value); |
270 | ||
271 | 4 | if (index < 0) |
272 | 1 | throw new ApplicationRuntimeException(UtilMessages.valueNotFound(value), value, null, |
273 | null); | |
274 | ||
275 | 3 | _lastValue = value; |
276 | ||
277 | 3 | return _keys.get(index); |
278 | } | |
279 | ||
280 | /** | |
281 | * Given a primary key, locates the corresponding object. May invoke | |
282 | * {@link #provideMissingValue(Object)} if no such key has been stored into the converter. | |
283 | * | |
284 | * @return the object if the key is found, or null otherwise. | |
285 | * @see #add(Object, Object) | |
286 | */ | |
287 | 7 | public final Object getValue(Object primaryKey) |
288 | { | |
289 | 7 | Object result = _map.get(primaryKey); |
290 | ||
291 | 7 | if (result == null) |
292 | 3 | result = provideMissingValue(primaryKey); |
293 | ||
294 | 6 | _lastValue = result; |
295 | ||
296 | 6 | return result; |
297 | } | |
298 | ||
299 | /** | |
300 | * Invoked by {@link #getValue(Object)} when the key is not found in the converter's map. | |
301 | * Subclasses may override this method to either obtain the corresponding object from secondary | |
302 | * storage, to throw an exception, or to provide a new object instance. This implementation | |
303 | * returns null. | |
304 | * | |
305 | * @param key | |
306 | * the key for which an object was requested | |
307 | * @return the object for the key, or null if no object may can be provided | |
308 | */ | |
309 | 1 | protected Object provideMissingValue(Object key) |
310 | { | |
311 | 1 | return null; |
312 | } | |
313 | ||
314 | } |
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