001 /* CompositeData.java -- A composite data structure implementation.
002 Copyright (C) 2006, 2007 Free Software Foundation, Inc.
003
004 This file is part of GNU Classpath.
005
006 GNU Classpath is free software; you can redistribute it and/or modify
007 it under the terms of the GNU General Public License as published by
008 the Free Software Foundation; either version 2, or (at your option)
009 any later version.
010
011 GNU Classpath is distributed in the hope that it will be useful, but
012 WITHOUT ANY WARRANTY; without even the implied warranty of
013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
014 General Public License for more details.
015
016 You should have received a copy of the GNU General Public License
017 along with GNU Classpath; see the file COPYING. If not, write to the
018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019 02110-1301 USA.
020
021 Linking this library statically or dynamically with other modules is
022 making a combined work based on this library. Thus, the terms and
023 conditions of the GNU General Public License cover the whole
024 combination.
025
026 As a special exception, the copyright holders of this library give you
027 permission to link this library with independent modules to produce an
028 executable, regardless of the license terms of these independent
029 modules, and to copy and distribute the resulting executable under
030 terms of your choice, provided that you also meet, for each linked
031 independent module, the terms and conditions of the license of that
032 module. An independent module is a module which is not derived from
033 or based on this library. If you modify this library, you may extend
034 this exception to your version of the library, but you are not
035 obligated to do so. If you do not wish to do so, delete this
036 exception statement from your version. */
037
038 package javax.management.openmbean;
039
040 import java.io.Serializable;
041
042 import java.util.Collection;
043 import java.util.Collections;
044 import java.util.Iterator;
045 import java.util.Map;
046 import java.util.Set;
047 import java.util.SortedMap;
048 import java.util.TreeMap;
049
050 /**
051 * Provides an implementation of the {@link CompositeData}
052 * interface.
053 *
054 * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
055 * @since 1.5
056 */
057 public class CompositeDataSupport
058 implements CompositeData, Serializable
059 {
060
061 /**
062 * Compatible with JDK 1.5
063 */
064 private static final long serialVersionUID = 8003518976613702244L;
065
066 /**
067 * Mapping of field names to values.
068 *
069 * @serial the map of field names to values.
070 */
071 private SortedMap<String, Object> contents;
072
073 /**
074 * The composite type which represents this composite data instance.
075 *
076 * @serial the type information for this instance.
077 */
078 private CompositeType compositeType;
079
080 /**
081 * Constructs a new {@link CompositeDataSupport} instance with the
082 * specified type using field names and values from the supplied map.
083 * The keys of the map become the field names, while the values
084 * become the values of each respective field. This constructor simply
085 * calls the other constructor, with the two arrays formed using the
086 * keys and values of this map, respectively. Thus, the input parameters
087 * given should conform to the same requirements given there (i.e. no
088 * null values or empty strings).
089 *
090 * @param type the composite type of this composite data structure.
091 * @param items a mapping of field names to values. This should match
092 * the mappings given by the type (i.e. for each mapping
093 * in the type, there should be a corresponding field name
094 * with a value of the correct type).
095 * @throws IllegalArgumentException if the type, the map or any of the keys
096 * or values in the map are <code>null</code>,
097 * or if any key from the map is an empty
098 * string.
099 * @throws OpenDataException if a mismatch occurs between the map and the
100 * field name/type specification given by the
101 * {@link CompositeType} instance. This may be
102 * due to the two having a different size, a
103 * mismatch between keys or an incorrectly typed
104 * value.
105 * @throws ArrayStoreException if one of the keys is not a
106 * {@link java.lang.String} (thus calling a failure
107 * in converting the keys to an array of strings).
108 */
109 public CompositeDataSupport(CompositeType type, Map<String, ?> items)
110 throws OpenDataException
111 {
112 this(type,
113 items.keySet().toArray(new String[items.size()]),
114 items.values().toArray());
115 }
116
117 /**
118 * Constructs a new {@link CompositeDataSupport} instance with the
119 * specified type using the supplied arrays of field names and
120 * values. Neither the type, the two arrays or any elements of the
121 * arrays may be <code>null</code>. The {@link java.lang.String}s
122 * within the <code>names</code> array must be non-empty. The
123 * arrays must match in size and order, as each element of the
124 * <code>names</code> array is matched against the corresponding
125 * value in the <code>values</code> array. Internally, the two are
126 * stored in a map, lexographically ordered using the field names.
127 * The data given should also conform to the description of the
128 * instance given by the {@link CompositeType} instance supplied.
129 *
130 * @param type the composite type of this composite data structure.
131 * @param names the field names.
132 * @param values the corresponding values of the fields.
133 * @throws IllegalArgumentException if the type, the arrays or any of the keys
134 * or values in the arrays are <code>null</code>,
135 * or if any key from <code>names</code> is
136 * an empty string. This also occurs if the
137 * arrays differ in length.
138 * @throws OpenDataException if a mismatch occurs between the arrays and the
139 * field name/type specification given by the
140 * {@link CompositeType} instance. This may be
141 * due to a differing number of field names, a
142 * mismatch between names or an incorrectly typed
143 * value.
144 */
145 public CompositeDataSupport(CompositeType type, String[] names, Object[] values)
146 throws OpenDataException
147 {
148 if (type == null)
149 throw new IllegalArgumentException("The given composite type is null.");
150 compositeType = type;
151 if (names == null)
152 throw new IllegalArgumentException("The names array is null.");
153 if (values == null)
154 throw new IllegalArgumentException("The values array is null.");
155 if (names.length != values.length)
156 throw new IllegalArgumentException("The sizes of the arrays differ.");
157 Set typeKeys = type.keySet();
158 if (typeKeys.size() != names.length)
159 throw new OpenDataException("The number of field names does not match " +
160 "the type description.");
161 contents = new TreeMap<String, Object>();
162 for (int a = 0; a < names.length; ++a)
163 {
164 if (names[a] == null)
165 throw new IllegalArgumentException("Element " + a + " of the names " +
166 "array is null.");
167 if (names[a].length() == 0)
168 throw new IllegalArgumentException("Element " + a + " of the names " +
169 "array is an empty string.");
170 if (values[a] == null)
171 throw new IllegalArgumentException("Element " + a + " of the values " +
172 "array is null.");
173 if (!(typeKeys.contains(names[a])))
174 throw new OpenDataException("The name, " + names[a] + ", is not a " +
175 "field in the given type description.");
176 if (!(type.getType(names[a]).isValue(values[a])))
177 throw new OpenDataException("The value, " + values[a] + ", is not a " +
178 "valid value for the " + names[a] + " field.");
179 contents.put(names[a], values[a]);
180 }
181 }
182
183 /**
184 * Returns true if this {@link CompositeData} instance contains
185 * the specified key. This method always returns false for
186 * an input key equal to <code>null</code> or the empty string.
187 *
188 * @param key the key to find in the structure.
189 * @return true if the key exists.
190 */
191 public boolean containsKey(String key)
192 {
193 if (key == null || key.length() == 0)
194 return false;
195 else
196 return contents.containsKey(key);
197 }
198
199 /**
200 * Returns true if this {@link CompositeData} instance has
201 * a value equal to that supplied.
202 *
203 * @param value the value to look for.
204 * @return true if the value exists.
205 */
206 public boolean containsValue(Object value)
207 {
208 return contents.containsValue(value);
209 }
210
211
212 /**
213 * Compares the specified object with this object for equality.
214 * The object is judged equivalent if it is non-null, and also
215 * an instance of {@link CompositeData} with the same name-value
216 * mappings and types. The two compared instances may be
217 * equivalent even if they represent different implementations of
218 * {@link CompositeData}.
219 *
220 * @param obj the object to compare for equality.
221 * @return true if <code>obj</code> is equal to <code>this</code>.
222 */
223 public boolean equals(Object obj)
224 {
225 if (!(obj instanceof CompositeData))
226 return false;
227 CompositeData data = (CompositeData) obj;
228 if (!(data.getCompositeType().equals(compositeType)))
229 return false;
230 Iterator it = contents.keySet().iterator();
231 while (it.hasNext())
232 {
233 String key = (String) it.next();
234 if (!(data.containsKey(key)))
235 return false;
236 if (!(data.get(key).equals(contents.get(key))))
237 return false;
238 }
239 return true;
240 }
241
242 /**
243 * Retrieves the value for the specified key.
244 *
245 * @param key the key whose value should be returned.
246 * @return the matching value.
247 * @throws IllegalArgumentException if the key is <code>null</code>
248 * or the empty string.
249 * @throws InvalidKeyException if the key does not exist.
250 */
251 public Object get(String key)
252 {
253 if (key == null)
254 throw new IllegalArgumentException("The supplied key is null.");
255 if (key.length() == 0)
256 throw new IllegalArgumentException("The supplied key is the empty string.");
257 if (!(contents.containsKey(key)))
258 throw new InvalidKeyException("The supplied key does not exist.");
259 return contents.get(key);
260 }
261
262 /**
263 * Returns the appropriate value for each key in the given array,
264 * using the same ordering.
265 *
266 * @param keys the keys whose values should be returned.
267 * @return the matching values.
268 * @throws IllegalArgumentException if one of the keys is
269 * <code>null</code> or the
270 * empty string.
271 * @throws InvalidKeyException if one of the keys does not exist.
272 */
273 public Object[] getAll(String[] keys)
274 {
275 Object[] values = new Object[keys.length];
276 for (int a = 0; a < keys.length; ++a)
277 values[a] = get(keys[a]);
278 return values;
279 }
280
281
282 /**
283 * Returns the composite type which corresponds to this instance
284 * of {@link CompositeData}.
285 *
286 * @return the composite type for this instance.
287 */
288 public CompositeType getCompositeType()
289 {
290 return compositeType;
291 }
292
293 /**
294 * Returns the hash code of this instance. The hash code is
295 * computed as the sum of the hash codes of all the values plus
296 * the hash code of the composite type. As equality comparisons
297 * take place using this same information, this should ensure that
298 * the property, <code>e1.equals(e2)</code> implies
299 * <code>e1.hashCode() == e2.hashCode(), holds for any pair
300 * of instances, <code>e1</code> and <code>e2</code>. However,
301 * this relies on the other instance implementing the
302 * <code>hashCode</code> method correctly, if it is not an
303 * instance of {@link CompositeDataSupport}.
304 *
305 * @return the hash code of this {@link CompositeData}.
306 * @see Object#equals(Object)
307 */
308 public int hashCode()
309 {
310 int code = compositeType.hashCode();
311 Iterator it = values().iterator();
312 while (it.hasNext())
313 code += it.next().hashCode();
314 return code;
315 }
316
317
318 /**
319 * Returns a textual representation of this instance. The
320 * exact format is left up to the implementation, but it
321 * should contain the name of the implementing class,
322 * the name of the type and a mapping of the form
323 * <code>key=value</code> for each pair of key and value.
324 *
325 * @return a {@link java.lang.String} representation of the
326 * object.
327 */
328 public String toString()
329 {
330 return getClass().getName() +
331 "[compositeType=" + compositeType +
332 ",contents=" + contents +
333 "]";
334 }
335
336 /**
337 * Returns a read-only collection of the values associated with
338 * this instance. The values are sorted using the lexicographic
339 * ordering of the corresponding keys.
340 *
341 * @return the values of this instance.
342 */
343 public Collection<?> values()
344 {
345 return Collections.unmodifiableCollection(contents.values());
346 }
347
348 }
349