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19 package org.eclipse.jetty.servlet.listener;
20
21 import java.lang.reflect.Field;
22 import java.util.Iterator;
23 import java.util.Map;
24 import java.util.concurrent.ConcurrentHashMap;
25
26 import javax.servlet.ServletContextEvent;
27 import javax.servlet.ServletContextListener;
28
29 import org.eclipse.jetty.util.Loader;
30 import org.eclipse.jetty.util.log.Log;
31 import org.eclipse.jetty.util.log.Logger;
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42 public class ELContextCleaner implements ServletContextListener
43 {
44 private static final Logger LOG = Log.getLogger(ELContextCleaner.class);
45
46
47 public void contextInitialized(ServletContextEvent sce)
48 {
49 }
50
51 public void contextDestroyed(ServletContextEvent sce)
52 {
53 try
54 {
55
56 Class<?> beanELResolver = Loader.loadClass(this.getClass(), "javax.el.BeanELResolver");
57
58
59 Field field = getField(beanELResolver);
60
61
62 purgeEntries(field);
63
64 if (LOG.isDebugEnabled())
65 LOG.debug("javax.el.BeanELResolver purged");
66 }
67
68 catch (ClassNotFoundException e)
69 {
70
71 }
72 catch (SecurityException | IllegalArgumentException | IllegalAccessException e)
73 {
74 LOG.warn("Cannot purge classes from javax.el.BeanELResolver", e);
75 }
76 catch (NoSuchFieldException e)
77 {
78 LOG.debug("Not cleaning cached beans: no such field javax.el.BeanELResolver.properties");
79 }
80
81 }
82
83
84 protected Field getField (Class<?> beanELResolver)
85 throws SecurityException, NoSuchFieldException
86 {
87 if (beanELResolver == null)
88 return null;
89
90 return beanELResolver.getDeclaredField("properties");
91 }
92
93 protected void purgeEntries (Field properties)
94 throws IllegalArgumentException, IllegalAccessException
95 {
96 if (properties == null)
97 return;
98
99 if (!properties.isAccessible())
100 properties.setAccessible(true);
101
102 Map map = (Map) properties.get(null);
103 if (map == null)
104 return;
105
106 Iterator<Class<?>> itor = map.keySet().iterator();
107 while (itor.hasNext())
108 {
109 Class<?> clazz = itor.next();
110 if (LOG.isDebugEnabled())
111 LOG.debug("Clazz: "+clazz+" loaded by "+clazz.getClassLoader());
112 if (Thread.currentThread().getContextClassLoader().equals(clazz.getClassLoader()))
113 {
114 itor.remove();
115 if (LOG.isDebugEnabled())
116 LOG.debug("removed");
117 }
118 else
119 {
120 if (LOG.isDebugEnabled())
121 LOG.debug("not removed: "+"contextclassloader="+Thread.currentThread().getContextClassLoader()+"clazz's classloader="+clazz.getClassLoader());
122 }
123 }
124 }
125 }