AttributeListUtils


1   /*
2    * The contents of this file are subject to the terms 
3    * of the Common Development and Distribution License 
4    * (the License).  You may not use this file except in
5    * compliance with the License.
6    * 
7    * You can obtain a copy of the license at 
8    * https://glassfish.dev.java.net/public/CDDLv1.0.html or
9    * glassfish/bootstrap/legal/CDDLv1.0.txt.
10   * See the License for the specific language governing 
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12   * 
13   * When distributing Covered Code, include this CDDL 
14   * Header Notice in each file and include the License file 
15   * at glassfish/bootstrap/legal/CDDLv1.0.txt.  
16   * If applicable, add the following below the CDDL Header, 
17   * with the fields enclosed by brackets [] replaced by
18   * you own identifying information: 
19   * "Portions Copyrighted [year] [name of copyright owner]"
20   * 
21   * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
22   */
23  
24  /*
25   * Copyright 2004-2005 Sun Microsystems, Inc.  All rights reserved.
26   * Use is subject to license terms.
27   */
28  
29  /*
30   * JmxNamedAttributeList.java
31   * $Id: AttributeListUtils.java,v 1.2 2005/12/25 03:53:18 tcfujii Exp $
32   * $Revision: 1.2 $
33   * $Date: 2005/12/25 03:53:18 $
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44  
45  package com.sun.enterprise.admin.util.jmx;
46  
47  import java.util.Iterator  ;
48  import java.util.Map  ;
49  import java.util.HashMap  ;
50  import java.util.ArrayList  ;
51  import javax.management.AttributeList  ;
52  import javax.management.Attribute  ;
53  import java.util.StringTokenizer  ;
54  
55  /** A class that has some useful utility methods to deal with
56   * <ul>
57   * <li> Jmx Attributes </li>
58   * <li> Jmx AttributeLists. </li>
59   * </ul>
60   * It is expected to enhance this class with more utility methods.
61   * @author  Kedar.Mhaswade@Sun.Com
62   * @since Sun Java System Application Server 8
63   */
64  public class AttributeListUtils {
65      
66      private AttributeListUtils() {
67          //disallow
68      }
69      
70      /** Checks whether this list contains a JMX {@link Attribute} with given name. Note that
71       * this method will return true if there is at least one attribute with given name.
72       * @param an instance of {@link AttributeList}
73       * @param name a String representing the name of the attribute. The name may not be null.
74       * @return true if there is at least one attribute in the list with given name,
75       * false otherwise
76       * @throws IllegalArgumentException if the attribute list or name is null 
77       */
78      public static final boolean containsNamedAttribute(final AttributeList   al,
79      final String   name) {
80          if (al == null || name == null)
81              throw new IllegalArgumentException   ("null arg");
82          boolean contains = false;
83          final Iterator   it = al.iterator();
84          while (it.hasNext()) {
85              final Attribute   at = (Attribute  ) it.next();
86              if (name.equals(at.getName())) { //attribute name may not be null - guaranteed
87                  contains = true;
88                  break;
89              }
90          }
91          return ( contains );
92      }
93      
94      /** Checks whether an attribute with the name same as that of the given
95       * attribute exists in this list. The given name may not be null.
96       * @param an instance of {@link AttributeList}
97       * @param a an Attribute with a name and a value
98       * @return true if there exists at least one attribute with same name, false
99       * otherwise
100      * @throws IllegalArgumentException if the attribute list or name is null 
101      */
102     public static final boolean containsNamedAttribute(final AttributeList   al,
103     final Attribute   a) {
104         if (al == null || a == null)
105             throw new IllegalArgumentException   ("null arg");
106         return ( containsNamedAttribute(al, a.getName()) );
107     }
108     
109     /** Returns the given list as a map of attributes, keyed on the names of the attribute
110      * in the list. The passed argument may not be null. The mappings are between
111      * the names of attributes and attributes themselves.
112      * @param the list of attributes that need to be mapped
113      * @return an instance of {@link Map}
114      * @throws IllegalArgumentException if the argument is null
115      */
116     public static final Map   asNameMap(final AttributeList   al) {
117         if (al == null) {
118             throw new IllegalArgumentException   ("null arg");
119         }
120         final Map   m         = new HashMap  ();
121         final Iterator   it   = al.iterator();
122         while (it.hasNext()) {
123             final Attribute   a = (Attribute  ) it.next();
124             m.put(a.getName(), a);
125         }
126         return ( m );
127     }
128     
129     /** JMX 1.2 specification had a weird limitation that a Dynamic MBean
130      * may not have an attribute whose name is <b> not a valid Java 
131      * identifier <b>. This method is a utility method to convert the any
132      * arbitrary name into a String that can be a valid JMX 1.2 attribute.
133      * Every character in the string passed that is neither a Character.isJavaIdentifierStart
134      * nor a Character.isJavaIdentifierPart is replace with a valid character
135      * '_'.
136      * @param a String that represents any non null name
137      * @return a String that represents a name valid for a JMX 1.2 MBean.
138      * @throws IllegalArgumentException if the parameter is null or is of zero length
139      */
140     public static final String   toJmx12Attribute(final String   name) {
141         if (name == null || name.length() == 0)
142             throw new IllegalArgumentException   ("invalid arg");
143         final char rc = '_';
144         assert (Character.isJavaIdentifierStart(rc) && Character.isJavaIdentifierPart(rc));
145         final char[] chars = new char[name.length()];
146         name.getChars(0, name.length(), chars, 0);
147         if (! Character.isJavaIdentifierStart(chars[0])) {
148             chars[0] = rc;
149         }
150         for (int i = 1 ; i < name.length() ; i++) { //note the index
151             if (! Character.isJavaIdentifierPart(chars[i])) {
152                 chars[i] = rc;
153             }
154         }
155         return ( new String  (chars) );
156     }
157     
158     /** Returns a String representation of an attribute list such that:
159      * <ul>
160      *  <li> Each attribute is a name and value separated by a ','. toString() on the value is called. </li>
161      *  <li> Each pair is separated by a new line character '\n'. </li>
162      * </ul>
163      * @param the list of attributes - may be null, in which case an empty String is returned.
164      * @return a String representing the parameter passed
165      */
166     public static final String   toString(final AttributeList   al) {
167         final StringBuffer   sb = new StringBuffer  ();
168         final char SEP = ',';
169         final char NL = '\n';
170         if (al != null) {
171             final Iterator   it = al.iterator();
172             while (it.hasNext()) {
173                 final Attribute   a = (Attribute  ) it.next();
174                 sb.append(a.getName()).append(SEP).append(a.getValue().toString()).append(NL);
175             }
176         }
177         return (sb.toString());
178     }
179     
180     public static String   dash2CamelCase(String   dashed) {
181         /* This algorithm is obviously not accurate, as I have not written
182          * a generic parser/lexical analyzer, nor have I written a BNF. All it
183          * does is it converts Strings  like abc-def-ghi to AbcDefGhi. A hyphen, if followed
184          * by an alphabet, will be removed and the alphabet is capitalized. No more
185          * complications. The passed String is converted into lower case by default.
186          */
187         if (dashed == null)
188             throw new IllegalArgumentException   ("Null Arg");
189         dashed = dashed.toLowerCase();
190         final ArrayList   list = new ArrayList  ();
191         final StringTokenizer   tz = new StringTokenizer  (dashed, "-");
192         while (tz.hasMoreTokens()) {
193             list.add(tz.nextToken());
194         }
195         final String  [] tmp = new String  [list.size()];
196         final String  [] strings = getCamelCaseArray((String  [])list.toArray(tmp));
197         return ( strings2String(strings) );
198     }
199     
200     private static String  [] getCamelCaseArray(final String  [] from) {
201         final String  [] humps = new String  [from.length];
202         for (int i = 0 ; i < from.length ; i++) {
203             final StringBuffer   sb = new StringBuffer  (from[i]);
204             sb.setCharAt(0, Character.toUpperCase(sb.charAt(0)));
205             humps[i] = sb.toString();
206         }
207         return ( humps );
208     }
209     private static String   strings2String(final String  [] a) {
210         final StringBuffer   sb = new StringBuffer  ();
211         for (int i = 0 ; i < a.length ; i++) {
212             sb.append(a[i]);
213         }
214         return ( sb.toString() );
215     }
216 }
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