1 /*

     2  * Copyright 2000-2007 Sun Microsystems, Inc.  All Rights Reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.  Sun designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Sun in the LICENSE file that accompanied this code.

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    14  * version 2 for more details (a copy is included in the LICENSE file that

    15  * accompanied this code).

    16  *

    17  * You should have received a copy of the GNU General Public License version

    18  * 2 along with this work; if not, write to the Free Software Foundation,

    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    20  *

    21  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

    22  * CA 95054 USA or visit www.sun.com if you need additional information or

    23  * have any questions.

    24  */

    25 

    26 

    27 package javax.management.openmbean;

    28 

    29 

    30 // java import

    31 //

    32 import java.util.ArrayList;

    33 import java.util.Collections;

    34 import java.util.Iterator;

    35 import java.util.List;

    36 

    37 // jmx import

    38 //

    39 

    40 

    41 /**

    42  * The <code>TabularType</code> class is the <i> open type</i> class

    43  * whose instances describe the types of {@link TabularData <code>TabularData</code>} values.

    44  *

    45  * @since 1.5

    46  */

    47 public class TabularType extends OpenType<TabularData> {

    48 

    49     /* Serial version */

    50     static final long serialVersionUID = 6554071860220659261L;

    51 

    52 

    53     /**

    54      * @serial The composite type of rows

    55      */

    56     private CompositeType  rowType;

    57 

    58     /**

    59      * @serial The items used to index each row element, kept in the order the user gave

    60      *         This is an unmodifiable {@link ArrayList}

    61      */

    62     private List<String> indexNames;

    63 

    64 

    65     private transient Integer myHashCode = null; // As this instance is immutable, these two values

    66     private transient String  myToString = null; // need only be calculated once.

    67 

    68 

    69     /* *** Constructor *** */

    70 

    71     /**

    72      * Constructs a <code>TabularType</code> instance, checking for the validity of the given parameters.

    73      * The validity constraints are described below for each parameter.

    74      * <p>

    75      * The Java class name of tabular data values this tabular type represents

    76      * (ie the class name returned by the {@link OpenType#getClassName() getClassName} method)

    77      * is set to the string value returned by <code>TabularData.class.getName()</code>.

    78      * <p>

    79      * @param  typeName  The name given to the tabular type this instance represents; cannot be a null or empty string.

    80      * <br>&nbsp;

    81      * @param  description  The human readable description of the tabular type this instance represents;

    82      *                      cannot be a null or empty string.

    83      * <br>&nbsp;

    84      * @param  rowType  The type of the row elements of tabular data values described by this tabular type instance;

    85      *                  cannot be null.

    86      * <br>&nbsp;

    87      * @param  indexNames  The names of the items the values of which are used to uniquely index each row element in the

    88      *                     tabular data values described by this tabular type instance;

    89      *                     cannot be null or empty. Each element should be an item name defined in <var>rowType</var>

    90      *                     (no null or empty string allowed).

    91      *                     It is important to note that the <b>order</b> of the item names in <var>indexNames</var>

    92      *                     is used by the methods {@link TabularData#get(java.lang.Object[]) <code>get</code>} and

    93      *                     {@link TabularData#remove(java.lang.Object[]) <code>remove</code>} of class

    94      *                     <code>TabularData</code> to match their array of values parameter to items.

    95      * <br>&nbsp;

    96      * @throws IllegalArgumentException  if <var>rowType</var> is null,

    97      *                                   or <var>indexNames</var> is a null or empty array,

    98      *                                   or an element in <var>indexNames</var> is a null or empty string,

    99      *                                   or <var>typeName</var> or <var>description</var> is a null or empty string.

   100      * <br>&nbsp;

   101      * @throws OpenDataException  if an element's value of <var>indexNames</var>

   102      *                            is not an item name defined in <var>rowType</var>.

   103      */

   104     public TabularType(String         typeName,

   105                        String         description,

   106                        CompositeType  rowType,

   107                        String[]       indexNames) throws OpenDataException {

   108 

   109         // Check and initialize state defined by parent.

   110         //

   111         super(TabularData.class.getName(), typeName, description, false);

   112 

   113         // Check rowType is not null

   114         //

   115         if (rowType == null) {

   116             throw new IllegalArgumentException("Argument rowType cannot be null.");

   117         }

   118 

   119         // Check indexNames is neither null nor empty and does not contain any null element or empty string

   120         //

   121         checkForNullElement(indexNames, "indexNames");

   122         checkForEmptyString(indexNames, "indexNames");

   123 

   124         // Check all indexNames values are valid item names for rowType

   125         //

   126         for (int i=0; i<indexNames.length; i++) {

   127             if ( ! rowType.containsKey(indexNames[i]) ) {

   128                 throw new OpenDataException("Argument's element value indexNames["+ i +"]=\""+ indexNames[i] +

   129                                             "\" is not a valid item name for rowType.");

   130             }

   131         }

   132 

   133         // initialize rowType

   134         //

   135         this.rowType    = rowType;

   136 

   137         // initialize indexNames (copy content so that subsequent

   138         // modifs to the array referenced by the indexNames parameter

   139         // have no impact)

   140         //

   141         List<String> tmpList = new ArrayList<String>(indexNames.length + 1);

   142         for (int i=0; i<indexNames.length; i++) {

   143             tmpList.add(indexNames[i]);

   144         }

   145         this.indexNames = Collections.unmodifiableList(tmpList);

   146     }

   147 

   148     /**

   149      * Checks that Object[] arg is neither null nor empty (ie length==0)

   150      * and that it does not contain any null element.

   151      */

   152     private static void checkForNullElement(Object[] arg, String argName) {

   153         if ( (arg == null) || (arg.length == 0) ) {

   154             throw new IllegalArgumentException("Argument "+ argName +"[] cannot be null or empty.");

   155         }

   156         for (int i=0; i<arg.length; i++) {

   157             if (arg[i] == null) {

   158                 throw new IllegalArgumentException("Argument's element "+ argName +"["+ i +"] cannot be null.");

   159             }

   160         }

   161     }

   162 

   163     /**

   164      * Checks that String[] does not contain any empty (or blank characters only) string.

   165      */

   166     private static void checkForEmptyString(String[] arg, String argName) {

   167         for (int i=0; i<arg.length; i++) {

   168             if (arg[i].trim().equals("")) {

   169                 throw new IllegalArgumentException("Argument's element "+ argName +"["+ i +"] cannot be an empty string.");

   170             }

   171         }

   172     }

   173 

   174 

   175     /* *** Tabular type specific information methods *** */

   176 

   177     /**

   178      * Returns the type of the row elements of tabular data values

   179      * described by this <code>TabularType</code> instance.

   180      *

   181      * @return the type of each row.

   182      */

   183     public CompositeType getRowType() {

   184 

   185         return rowType;

   186     }

   187 

   188     /**

   189      * <p>Returns, in the same order as was given to this instance's

   190      * constructor, an unmodifiable List of the names of the items the

   191      * values of which are used to uniquely index each row element of

   192      * tabular data values described by this <code>TabularType</code>

   193      * instance.</p>

   194      *

   195      * @return a List of String representing the names of the index

   196      * items.

   197      *

   198      */

   199     public List<String> getIndexNames() {

   200 

   201         return indexNames;

   202     }

   203 

   204     /**

   205      * Tests whether <var>obj</var> is a value which could be

   206      * described by this <code>TabularType</code> instance.

   207      *

   208      * <p>If <var>obj</var> is null or is not an instance of

   209      * <code>javax.management.openmbean.TabularData</code>,

   210      * <code>isValue</code> returns <code>false</code>.</p>

   211      *

   212      * <p>If <var>obj</var> is an instance of

   213      * <code>javax.management.openmbean.TabularData</code>, say {@code

   214      * td}, the result is true if this {@code TabularType} is

   215      * <em>assignable from</em> {@link TabularData#getTabularType()

   216      * td.getTabularType()}, as defined in {@link

   217      * CompositeType#isValue CompositeType.isValue}.</p>

   218      *

   219      * @param obj the value whose open type is to be tested for

   220      * compatibility with this <code>TabularType</code> instance.

   221      *

   222      * @return <code>true</code> if <var>obj</var> is a value for this

   223      * tabular type, <code>false</code> otherwise.

   224      */

   225     public boolean isValue(Object obj) {

   226 

   227         // if obj is null or not a TabularData, return false

   228         //

   229         if (!(obj instanceof TabularData))

   230             return false;

   231 

   232         // if obj is not a TabularData, return false

   233         //

   234         TabularData value = (TabularData) obj;

   235         TabularType valueType = value.getTabularType();

   236         return isAssignableFrom(valueType);

   237     }

   238 

   239     @Override

   240     boolean isAssignableFrom(OpenType ot) {

   241         if (!(ot instanceof TabularType))

   242             return false;

   243         TabularType tt = (TabularType) ot;

   244         if (!getTypeName().equals(tt.getTypeName()) ||

   245                 !getIndexNames().equals(tt.getIndexNames()))

   246             return false;

   247         return getRowType().isAssignableFrom(tt.getRowType());

   248     }

   249 

   250 

   251     /* *** Methods overriden from class Object *** */

   252 

   253     /**

   254      * Compares the specified <code>obj</code> parameter with this <code>TabularType</code> instance for equality.

   255      * <p>

   256      * Two <code>TabularType</code> instances are equal if and only if all of the following statements are true:

   257      * <ul>

   258      * <li>their type names are equal</li>

   259      * <li>their row types are equal</li>

   260      * <li>they use the same index names, in the same order</li>

   261      * </ul>

   262      * <br>&nbsp;

   263      * @param  obj  the object to be compared for equality with this <code>TabularType</code> instance;

   264      *              if <var>obj</var> is <code>null</code>, <code>equals</code> returns <code>false</code>.

   265      *

   266      * @return  <code>true</code> if the specified object is equal to this <code>TabularType</code> instance.

   267      */

   268     public boolean equals(Object obj) {

   269 

   270         // if obj is null, return false

   271         //

   272         if (obj == null) {

   273             return false;

   274         }

   275 

   276         // if obj is not a TabularType, return false

   277         //

   278         TabularType other;

   279         try {

   280             other = (TabularType) obj;

   281         } catch (ClassCastException e) {

   282             return false;

   283         }

   284 

   285         // Now, really test for equality between this TabularType instance and the other:

   286         //

   287 

   288         // their names should be equal

   289         if ( ! this.getTypeName().equals(other.getTypeName()) ) {

   290             return false;

   291         }

   292 

   293         // their row types should be equal

   294         if ( ! this.rowType.equals(other.rowType) ) {

   295             return false;

   296         }

   297 

   298         // their index names should be equal and in the same order (ensured by List.equals())

   299         if ( ! this.indexNames.equals(other.indexNames) ) {

   300             return false;

   301         }

   302 

   303         // All tests for equality were successfull

   304         //

   305         return true;

   306     }

   307 

   308     /**

   309      * Returns the hash code value for this <code>TabularType</code> instance.

   310      * <p>

   311      * The hash code of a <code>TabularType</code> instance is the sum of the hash codes

   312      * of all elements of information used in <code>equals</code> comparisons

   313      * (ie: name, row type, index names).

   314      * This ensures that <code> t1.equals(t2) </code> implies that <code> t1.hashCode()==t2.hashCode() </code>

   315      * for any two <code>TabularType</code> instances <code>t1</code> and <code>t2</code>,

   316      * as required by the general contract of the method

   317      * {@link Object#hashCode() Object.hashCode()}.

   318      * <p>

   319      * As <code>TabularType</code> instances are immutable, the hash code for this instance is calculated once,

   320      * on the first call to <code>hashCode</code>, and then the same value is returned for subsequent calls.

   321      *

   322      * @return  the hash code value for this <code>TabularType</code> instance

   323      */

   324     public int hashCode() {

   325 

   326         // Calculate the hash code value if it has not yet been done (ie 1st call to hashCode())

   327         //

   328         if (myHashCode == null) {

   329             int value = 0;

   330             value += this.getTypeName().hashCode();

   331             value += this.rowType.hashCode();

   332             for (Iterator k = indexNames.iterator(); k.hasNext();  ) {

   333                 value += k.next().hashCode();

   334             }

   335             myHashCode = new Integer(value);

   336         }

   337 

   338         // return always the same hash code for this instance (immutable)

   339         //

   340         return myHashCode.intValue();

   341     }

   342 

   343     /**

   344      * Returns a string representation of this <code>TabularType</code> instance.

   345      * <p>

   346      * The string representation consists of the name of this class (ie <code>javax.management.openmbean.TabularType</code>),

   347      * the type name for this instance, the row type string representation of this instance,

   348      * and the index names of this instance.

   349      * <p>

   350      * As <code>TabularType</code> instances are immutable, the string representation for this instance is calculated once,

   351      * on the first call to <code>toString</code>, and then the same value is returned for subsequent calls.

   352      *

   353      * @return  a string representation of this <code>TabularType</code> instance

   354      */

   355     public String toString() {

   356 

   357         // Calculate the string representation if it has not yet been done (ie 1st call to toString())

   358         //

   359         if (myToString == null) {

   360             final StringBuilder result = new StringBuilder()

   361                 .append(this.getClass().getName())

   362                 .append("(name=")

   363                 .append(getTypeName())

   364                 .append(",rowType=")

   365                 .append(rowType.toString())

   366                 .append(",indexNames=(");

   367             int i=0;

   368             Iterator k = indexNames.iterator();

   369             while( k.hasNext() ) {

   370                 if (i > 0) result.append(",");

   371                 result.append(k.next().toString());

   372                 i++;

   373             }

   374             result.append("))");

   375             myToString = result.toString();

   376         }

   377 

   378         // return always the same string representation for this instance (immutable)

   379         //

   380         return myToString;

   381     }

   382 

   383 }