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1
7 package winstone.classLoader;
8
9 import java.io.File  ;
10 import java.io.IOException ;
11 import java.net.URL ;
12 import java.net.URLClassLoader ;
13 import java.util.Date ;
14 import java.util.Enumeration ;
15 import java.util.HashMap ;
16 import java.util.HashSet ;
17 import java.util.Map ;
18 import java.util.Set ;
19 import java.util.jar.JarEntry ;
20 import java.util.jar.JarFile ;
21
22 import javax.servlet.ServletContextEvent ;
23 import javax.servlet.ServletContextListener ;
24
25 import winstone.Logger;
26 import winstone.WebAppConfiguration;
27 import winstone.WinstoneResourceBundle;
28
29
37 public class ReloadingClassLoader extends URLClassLoader implements ServletContextListener , Runnable {
38 private static final int RELOAD_SEARCH_SLEEP = 50;
39 private static final WinstoneResourceBundle CL_RESOURCES = new WinstoneResourceBundle("winstone.classLoader.LocalStrings");
40 private boolean interrupted;
41 private WebAppConfiguration webAppConfig;
42 private Set loadedClasses;
43 private File classPaths[];
44 private int classPathsLength;
45
46 public ReloadingClassLoader(URL urls[], ClassLoader parent) {
47 super(urls, parent);
48 this.loadedClasses = new HashSet ();
49 if (urls != null) {
50 this.classPaths = new File [urls.length];
51 for (int n = 0 ; n < urls.length; n++) {
52 this.classPaths[this.classPathsLength++] = new File (urls[n].getFile());
53 }
54 }
55 }
56
57 protected void addURL(URL url) {
58 super.addURL(url);
59 synchronized (this.loadedClasses) {
60 if (this.classPaths == null) {
61 this.classPaths = new File [10];
62 this.classPathsLength = 0;
63 } else if (this.classPathsLength == (this.classPaths.length - 1)) {
64 File temp[] = this.classPaths;
65 this.classPaths = new File [(int) (this.classPathsLength * 1.75)];
66 System.arraycopy(temp, 0, this.classPaths, 0, this.classPathsLength);
67 }
68 this.classPaths[this.classPathsLength++] = new File (url.getFile());
69 }
70 }
71
72 public void contextInitialized(ServletContextEvent sce) {
73 this.webAppConfig = (WebAppConfiguration) sce.getServletContext();
74 this.interrupted = false;
75 synchronized (this) {
76 this.loadedClasses.clear();
77 }
78 Thread thread = new Thread (this, CL_RESOURCES
79 .getString("ReloadingClassLoader.ThreadName"));
80 thread.setDaemon(true);
81 thread.setPriority(Thread.MIN_PRIORITY);
82 thread.start();
83 }
84
85 public void contextDestroyed(ServletContextEvent sce) {
86 this.interrupted = true;
87 this.webAppConfig = null;
88 synchronized (this) {
89 this.loadedClasses.clear();
90 }
91 }
92
93
97 public void run() {
98 Logger.log(Logger.FULL_DEBUG, CL_RESOURCES,
99 "ReloadingClassLoader.MaintenanceThreadStarted");
100
101 Map classDateTable = new HashMap ();
102 Map classLocationTable = new HashMap ();
103 Set lostClasses = new HashSet ();
104 while (!interrupted) {
105 try {
106 Thread.sleep(RELOAD_SEARCH_SLEEP);
107 String loadedClassesCopy[] = null;
108 synchronized (this) {
109 loadedClassesCopy = (String []) this.loadedClasses.toArray(new String [0]);
110 }
111
112 for (int n = 0; (n < loadedClassesCopy.length) && !interrupted; n++) {
113 String className = transformToFileFormat(loadedClassesCopy[n]);
114 File location = (File ) classLocationTable.get(className);
115 Long classDate = null;
116 if ((location == null) || !location.exists()) {
117 for (int j = 0; (j < this.classPaths.length) && (classDate == null); j++) {
118 File path = this.classPaths[j];
119 if (!path.exists()) {
120 continue;
121 } else if (path.isDirectory()) {
122 File classLocation = new File (path, className);
123 if (classLocation.exists()) {
124 classDate = new Long (classLocation.lastModified());
125 classLocationTable.put(className, classLocation);
126 }
127 } else if (path.isFile()) {
128 classDate = searchJarPath(className, path);
129 if (classDate != null)
130 classLocationTable.put(className, path);
131 }
132 }
133 } else if (location.exists())
134 classDate = new Long (location.lastModified());
135
136 if (classDate == null) {
138 if (!lostClasses.contains(className)) {
139 lostClasses.add(className);
140 Logger.log(Logger.DEBUG, CL_RESOURCES,
141 "ReloadingClassLoader.ClassLost", className);
142 }
143 continue;
144 }
145 if ((classDate != null) && lostClasses.contains(className)) {
146 lostClasses.remove(className);
147 }
148
149 Long oldClassDate = (Long ) classDateTable.get(className);
152 if (oldClassDate == null) {
153 classDateTable.put(className, classDate);
154 } else if (oldClassDate.compareTo(classDate) != 0) {
155 Logger.log(Logger.INFO, CL_RESOURCES,
157 "ReloadingClassLoader.ReloadRequired",
158 new String [] {className,
159 "" + new Date (classDate.longValue()),
160 "" + new Date (oldClassDate.longValue()) });
161 this.webAppConfig.resetClassLoader();
162 }
163 }
164 } catch (Throwable err) {
165 Logger.log(Logger.ERROR, CL_RESOURCES,
166 "ReloadingClassLoader.MaintenanceThreadError", err);
167 }
168 }
169 Logger.log(Logger.FULL_DEBUG, CL_RESOURCES,
170 "ReloadingClassLoader.MaintenanceThreadFinished");
171 }
172
173 protected Class findClass(String name) throws ClassNotFoundException {
174 synchronized (this) {
175 this.loadedClasses.add("Class:" + name);
176 }
177 return super.findClass(name);
178 }
179
180 public URL findResource(String name) {
181 synchronized (this) {
182 this.loadedClasses.add(name);
183 }
184 return super.findResource(name);
185 }
186
187
190 private Long searchJarPath(String classResourceName, File path)
191 throws IOException , InterruptedException {
192 JarFile jar = new JarFile (path);
193 for (Enumeration e = jar.entries(); e.hasMoreElements() && !interrupted;) {
194 JarEntry entry = (JarEntry ) e.nextElement();
195 if (entry.getName().equals(classResourceName))
196 return new Long (path.lastModified());
197 }
198 return null;
199 }
200
201 private static String transformToFileFormat(String name) {
202 if (!name.startsWith("Class:"))
203 return name;
204 else
205 return WinstoneResourceBundle.globalReplace(name.substring(6), ".", "/") + ".class";
206 }
207 }
208 |
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