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35 package com.sun.enterprise.admin.monitor.stats;
36
37 import java.lang.reflect.Method  ;
38 import java.util.Iterator ;
39 import java.util.Map ;
40 import java.util.ArrayList ;
41 import java.util.HashMap ;
42 import javax.management.j2ee.statistics.Stats ;
43 import javax.management.j2ee.statistics.Statistic ;
44
45
57 public class GenericStatsImpl implements Stats {
58
59 private final Class statsInterface;
60 private final Object statsProvider;
61
62 private final Map getters;
63
64
66 public GenericStatsImpl(String statsInterfaceName, Object statsProvider)
67 throws ClassNotFoundException {
68 this(statsInterfaceName, GenericStatsImpl.class.getClassLoader(), statsProvider);
69 }
70
71
73 public GenericStatsImpl(String statsInterfaceName, ClassLoader loader,
74 Object statsProvider) throws ClassNotFoundException {
75 this(Class.forName(statsInterfaceName, true, loader), statsProvider);
76 }
77
78
90 public GenericStatsImpl(Class statsInterface, Object statsProvider) {
91 if (! implementsInterface(statsInterface, statsProvider) ||
92 ! extendsStatsInterface(statsInterface)) {
93 throw new IllegalArgumentException ("Contract violation: invalid interface-implementation pair");
94 }
95 this.statsProvider = statsProvider;
96 this.statsInterface = statsInterface;
97 this.getters = new HashMap ();
98 populateGetterMap();
99 }
100
101 public Statistic getStatistic(String statisticName) {
102 final Method getter = (Method ) getters.get(statisticName);
103 assert (getter != null) : ("Getter not initialized properly: " + statisticName);
104 Object result = null;
105 try {
106 result = getter.invoke(statsProvider);
107 }
108 catch(Exception e) {
109 final RuntimeException oe = new IllegalStateException ();
110 oe.initCause(e);
111 throw oe;
112 }
113 return ( (Statistic )result );
114 }
115
116 public String [] getStatisticNames() {
117
118 final String [] names = new String [getters.size()];
119 return ( (String [])getters.keySet().toArray(names) ); }
121
122 public Statistic [] getStatistics() {
123 return ( getStatisticsOneByOne() ); }
125
126 private Statistic [] getStatisticsOneByOne() {
127 final Iterator iter = getters.keySet().iterator();
128 final Statistic [] stats = new Statistic [getters.keySet().size()];
129 int i = 0;
130 while (iter.hasNext()) {
131 final String sn = (String ) iter.next();
132 stats[i++] = this.getStatistic(sn);
133 }
134 assert (stats.length == i);
135 return ( stats );
136 }
137
138 private boolean implementsInterface(Class c, Object o) {
139 boolean impls = false;
140 final Class [] interfaces = o.getClass().getInterfaces();
141 for (int i = 0 ; i < interfaces.length ; i++) {
142 if (interfaces[i].equals(c)){
143 impls = true;
144 break;
145 }
146 }
147 return ( impls );
148 }
149
150 private boolean extendsStatsInterface(Class i) {
151 final Class statsInterface = javax.management.j2ee.statistics.Stats .class;
152 return ( statsInterface.isAssignableFrom(i) );
153 }
154
155 private void populateGetterMap() {
156 final Method [] m = statsInterface.getMethods();
159 final Method [] apis = filterStatsMethods(m);
161 final Method [] methods = getGetters(apis);
162 final String [] names = methods2Statistics(methods);
163 assert (names.length == methods.length) : ("Statistic names array is not having same length as that of array of getters");
164 int i;
165 for (i = 0 ; i < names.length ; i++) {
166 getters.put(names[i], methods[i]);
167 }
168 assert (getters.size() == i) : ("Getters map is incorrect, names.length = " + names.length + " methods.length = " + methods.length);
169 }
170
171 private Method [] getGetters(Method [] all) {
172 final ArrayList l = new ArrayList ();
173 for (int i = 0 ; i < all.length ; i++) {
174 final Method am = all[i];
175 if (isValidGetter(am)) {
176 l.add(am);
177 }
178 }
179 final Method [] m = new Method [l.size()];
180 return ( (Method [])l.toArray(m) );
181 }
182
183 private boolean isValidGetter(Method m) {
184 final boolean startsWithGet = m.getName().startsWith("get");
185 final boolean hasNoParams = m.getParameterTypes().length == 0;
186 final boolean returnsStatistic = Statistic .class.isAssignableFrom(m.getReturnType());
187
188 return ( startsWithGet && hasNoParams && returnsStatistic );
189 }
190
191 private String [] methods2Statistics(Method [] methods) {
192 final String [] names = new String [methods.length];
193 for (int i = 0 ; i < methods.length ; i++) {
194 final String m = methods[i].getName();
195 final int s = "get".length();
196 names[i] = m.substring(s);
197 }
198 return ( names );
199 }
200
201 private boolean isStatsInterfaceMethod(String name) {
202 final Method [] methods = javax.management.j2ee.statistics.Stats .class.getMethods();
203 boolean isInterfaceMethod = false;
204 for (int i = 0 ; i < methods.length ; i++) {
205 if (methods[i].getName().equals(name)) {
206 isInterfaceMethod = true;
207 break;
208 }
209 }
210 return ( isInterfaceMethod );
211 }
212
213 private Method [] filterStatsMethods(Method [] m) {
214 ArrayList methodList = new ArrayList ();
215 for(int i = 0; i < m.length; i++) {
216 if(! isStatsInterfaceMethod(m[i].getName()))
217 methodList.add(m[i]);
218 }
219 final Method [] methods = new Method [methodList.size()];
220 return (Method [])methodList.toArray(methods);
221 }
222 }
223 |
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