TabularType


1   /*
2    * @(#)TabularType.java 3.22 03/12/19
3    * 
4    * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
5    * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
6    */
7   
8   
9   package javax.management.openmbean;
10  
11  
12  // java import
13  //
14  import java.io.Serializable  ;
15  import java.util.List  ;
16  import java.util.Iterator  ;
17  import java.util.Arrays  ;
18  import java.util.ArrayList  ;
19  import java.util.Collections  ;
20  
21  // jmx import
22  //
23  
24  
25  /**
26   * The <code>TabularType</code> class is the <i> open type</i> class 
27   * whose instances describe the types of {@link TabularData <code>TabularData</code>} values.
28   *
29   * @version     3.22  03/12/19
30   * @author      Sun Microsystems, Inc.
31   *
32   * @since 1.5
33   * @since.unbundled JMX 1.1
34   */
35  public class TabularType 
36      extends OpenType  
37      implements Serializable   {
38      
39      
40      /* Serial version */
41      static final long serialVersionUID = 6554071860220659261L;
42  
43  
44      /**
45       * @serial The composite type of rows
46       */
47      private CompositeType    rowType;
48      
49      /**
50       * @serial The items used to index each row element, kept in the order the user gave
51       *         This is an unmodifiable {@link ArrayList}
52       */
53      private List          indexNames;
54  
55  
56      private transient Integer   myHashCode = null; // As this instance is immutable, these two values
57      private transient String    myToString = null; // need only be calculated once.
58  
59  
60      /* *** Constructor *** */
61  
62      /**
63       * Constructs a <code>TabularType</code> instance, checking for the validity of the given parameters.
64       * The validity constraints are described below for each parameter. 
65       * <p>
66       * The Java class name of tabular data values this tabular type represents 
67       * (ie the class name returned by the {@link OpenType#getClassName() getClassName} method) 
68       * is set to the string value returned by <code>TabularData.class.getName()</code>.
69       * <p>
70       * @param  typeName  The name given to the tabular type this instance represents; cannot be a null or empty string.
71       * <br>&nbsp;
72       * @param  description  The human readable description of the tabular type this instance represents; 
73       *              cannot be a null or empty string.
74       * <br>&nbsp;
75       * @param  rowType  The type of the row elements of tabular data values described by this tabular type instance;
76       *          cannot be null.
77       * <br>&nbsp;
78       * @param  indexNames  The names of the items the values of which are used to uniquely index each row element in the 
79       *             tabular data values described by this tabular type instance; 
80       *             cannot be null or empty. Each element should be an item name defined in <var>rowType</var>
81       *             (no null or empty string allowed).
82       *             It is important to note that the <b>order</b> of the item names in <var>indexNames</var>
83       *                     is used by the methods {@link TabularData#get(java.lang.Object[]) <code>get</code>} and 
84       *             {@link TabularData#remove(java.lang.Object[]) <code>remove</code>} of class  
85       *             <code>TabularData</code> to match their array of values parameter to items.
86       * <br>&nbsp;
87       * @throws IllegalArgumentException  if <var>rowType</var> is null, 
88       *                   or <var>indexNames</var> is a null or empty array,
89       *                   or an element in <var>indexNames</var> is a null or empty string,
90       *                   or <var>typeName</var> or <var>description</var> is a null or empty string.
91       * <br>&nbsp;
92       * @throws OpenDataException  if an element's value of <var>indexNames</var> 
93       *                is not an item name defined in <var>rowType</var>.
94       */
95      public TabularType(String           typeName, 
96                 String           description, 
97                 CompositeType    rowType,
98                 String  []       indexNames) throws OpenDataException   {
99      
100     // Check and initialize state defined by parent.
101     //
102     super(TabularData  .class.getName(), typeName, description);
103     
104     // Check rowType is not null
105     //
106     if (rowType == null) {
107         throw new IllegalArgumentException  ("Argument rowType cannot be null.");
108     }   
109 
110     // Check indexNames is neither null nor empty and does not contain any null element or empty string
111     //
112     checkForNullElement(indexNames, "indexNames");
113     checkForEmptyString(indexNames, "indexNames");
114 
115     // Check all indexNames values are valid item names for rowType
116     //
117     for (int i=0; i<indexNames.length; i++) {
118         if ( ! rowType.containsKey(indexNames[i]) ) {
119         throw new OpenDataException  ("Argument's element value indexNames["+ i +"]=\""+ indexNames[i] +
120                         "\" is not a valid item name for rowType.");
121         }   
122     }
123     
124     // initialize rowType 
125     //
126     this.rowType    = rowType;
127 
128     // initialize indexNames 
129     // (copy content so that subsequent modif to the array referenced by the indexNames parameter have no impact)
130     //
131     ArrayList   tmpList = new ArrayList  (indexNames.length + 1);
132     for (int i=0; i<indexNames.length; i++) {
133         tmpList.add(indexNames[i]);
134     }
135     this.indexNames = Collections.unmodifiableList(tmpList);
136     }
137     
138     /**
139      * Checks that Object[] arg is neither null nor empty (ie length==0) 
140      * and that it does not contain any null element.
141      */
142     private static void checkForNullElement(Object  [] arg, String   argName) {
143     if ( (arg == null) || (arg.length == 0) ) {
144         throw new IllegalArgumentException  ("Argument "+ argName +"[] cannot be null or empty.");
145     }
146     for (int i=0; i<arg.length; i++) {
147         if (arg[i] == null) {
148         throw new IllegalArgumentException  ("Argument's element "+ argName +"["+ i +"] cannot be null.");
149         }
150     }
151     }
152 
153     /**
154      * Checks that String[] does not contain any empty (or blank characters only) string.
155      */
156     private static void checkForEmptyString(String  [] arg, String   argName) {
157     for (int i=0; i<arg.length; i++) {
158         if (arg[i].trim().equals("")) {
159         throw new IllegalArgumentException  ("Argument's element "+ argName +"["+ i +"] cannot be an empty string.");
160         }
161     }
162     }
163 
164 
165     /* *** Tabular type specific information methods *** */
166 
167     /**
168      * Returns the type of the row elements of tabular data values
169      * described by this <code>TabularType</code> instance.
170      *
171      * @return the type of each row.
172      */
173     public CompositeType   getRowType() {
174 
175     return rowType;
176     }
177 
178     /**
179      * <p>Returns, in the same order as was given to this instance's
180      * constructor, an unmodifiable List of the names of the items the
181      * values of which are used to uniquely index each row element of
182      * tabular data values described by this <code>TabularType</code>
183      * instance.</p>
184      *
185      * @return a List of String representing the names of the index
186      * items.
187      * 
188      */
189     public List   getIndexNames() {
190 
191     return indexNames;
192     }
193 
194     /**
195      * Tests whether <var>obj</var> is a value which could be described by this <code>TabularType</code> instance.
196      * <p>
197      * If <var>obj</var> is null or is not an instance of <code>javax.management.openmbean.TabularData</code>,
198      * <code>isValue</code> returns <code>false</code>. 
199      * If <var>obj</var> is an instance of <code>javax.management.openmbean.TabularData</code>,
200      * its tabular type is tested for equality with this tabular type instance, and <code>isValue</code>
201      * returns <code>true</code> if and only if {@link #equals(java.lang.Object) <code>equals</code>} 
202      * returns <code>true</code>.
203      * <br>&nbsp;
204      * @param  obj  the value whose open type is to be tested for equality with this <code>TabularType</code> instance.
205      *
206      * @return <code>true</code> if <var>obj</var> is a value for this tabular type, <code>false</code> otherwise.
207      */
208     public boolean isValue(Object   obj) {
209 
210     // if obj is null, return false
211     //
212     if (obj == null) {
213         return false;
214     }
215 
216     // if obj is not a TabularData, return false
217     //
218     TabularData   value;
219     try {
220         value = (TabularData  ) obj;
221     } catch (ClassCastException   e) {
222         return false;
223     }
224 
225     // test value's TabularType for equality with this TabularType instance
226     //
227     return this.equals(value.getTabularType());
228     }
229 
230 
231     /* *** Methods overriden from class Object *** */
232 
233     /**
234      * Compares the specified <code>obj</code> parameter with this <code>TabularType</code> instance for equality. 
235      * <p>
236      * Two <code>TabularType</code> instances are equal if and only if all of the following statements are true:
237      * <ul>
238      * <li>their type names are equal</li>
239      * <li>their row types are equal</li>
240      * <li>they use the same index names, in the same order</li>
241      * </ul>
242      * <br>&nbsp;
243      * @param  obj  the object to be compared for equality with this <code>TabularType</code> instance;
244      *          if <var>obj</var> is <code>null</code>, <code>equals</code> returns <code>false</code>.
245      * 
246      * @return  <code>true</code> if the specified object is equal to this <code>TabularType</code> instance.
247      */
248     public boolean equals(Object   obj) {
249 
250     // if obj is null, return false
251     //
252     if (obj == null) {
253         return false;
254     }
255 
256     // if obj is not a TabularType, return false
257     //
258     TabularType   other;
259     try {
260         other = (TabularType  ) obj;
261     } catch (ClassCastException   e) {
262         return false;
263     }
264 
265     // Now, really test for equality between this TabularType instance and the other:
266     //
267     
268     // their names should be equal
269     if ( ! this.getTypeName().equals(other.getTypeName()) ) {
270         return false;
271     }
272 
273     // their row types should be equal
274     if ( ! this.rowType.equals(other.rowType) ) {
275         return false;
276     }
277 
278     // their index names should be equal and in the same order (ensured by List.equals())
279     if ( ! this.indexNames.equals(other.indexNames) ) {
280         return false;
281     }
282 
283     // All tests for equality were successfull
284     //
285     return true;
286     }
287 
288     /**
289      * Returns the hash code value for this <code>TabularType</code> instance. 
290      * <p>
291      * The hash code of a <code>TabularType</code> instance is the sum of the hash codes
292      * of all elements of information used in <code>equals</code> comparisons 
293      * (ie: name, row type, index names). 
294      * This ensures that <code> t1.equals(t2) </code> implies that <code> t1.hashCode()==t2.hashCode() </code> 
295      * for any two <code>TabularType</code> instances <code>t1</code> and <code>t2</code>, 
296      * as required by the general contract of the method
297      * {@link Object#hashCode() Object.hashCode()}.
298      * <p>
299      * As <code>TabularType</code> instances are immutable, the hash code for this instance is calculated once,
300      * on the first call to <code>hashCode</code>, and then the same value is returned for subsequent calls.
301      *
302      * @return  the hash code value for this <code>TabularType</code> instance
303      */
304     public int hashCode() {
305 
306     // Calculate the hash code value if it has not yet been done (ie 1st call to hashCode())
307     //
308     if (myHashCode == null) {
309         int value = 0;
310         value += this.getTypeName().hashCode();
311         value += this.rowType.hashCode();
312         for (Iterator   k = indexNames.iterator(); k.hasNext();  ) {
313         value += k.next().hashCode();
314         }
315         myHashCode = new Integer  (value);
316     }
317     
318     // return always the same hash code for this instance (immutable)
319     //
320     return myHashCode.intValue();
321     }
322 
323     /**
324      * Returns a string representation of this <code>TabularType</code> instance. 
325      * <p>
326      * The string representation consists of the name of this class (ie <code>javax.management.openmbean.TabularType</code>), 
327      * the type name for this instance, the row type string representation of this instance,
328      * and the index names of this instance.
329      * <p>
330      * As <code>TabularType</code> instances are immutable, the string representation for this instance is calculated once,
331      * on the first call to <code>toString</code>, and then the same value is returned for subsequent calls.
332      * 
333      * @return  a string representation of this <code>TabularType</code> instance
334      */
335     public String   toString() {
336 
337     // Calculate the string representation if it has not yet been done (ie 1st call to toString())
338     //
339     if (myToString == null) {
340         StringBuffer   result = new StringBuffer  ()
341         .append(this.getClass().getName())
342         .append("(name=")
343         .append(getTypeName())
344         .append(",rowType=")
345         .append(rowType.toString())
346         .append(",indexNames=(");
347         int i=0;
348         Iterator   k = indexNames.iterator();
349         while( k.hasNext() ) {
350         if (i > 0) result.append(",");
351         result.append(k.next().toString());
352         i++;
353         }
354         result.append("))");
355         myToString = result.toString();
356     }
357 
358     // return always the same string representation for this instance (immutable)
359     //
360     return myToString;
361     }
362 
363 }
364
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