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1
28
29
33 package net.sf.jasperreports.engine.design;
34
35 import java.io.Serializable  ;
36 import java.util.Map ;
37
38 import org.apache.commons.collections.ReferenceMap;
39
40 import net.sf.jasperreports.engine.JRException;
41 import net.sf.jasperreports.engine.fill.JREvaluator;
42 import net.sf.jasperreports.engine.util.JRClassLoader;
43
44
45
49 public abstract class JRAbstractJavaCompiler extends JRAbstractCompiler
50 {
51
52 private static ThreadLocal classFromBytesRef = new ThreadLocal ();
55
56
57 private static Object CLASS_CACHE_NULL_KEY = new Object ();
58 private static Map classCache = new ReferenceMap(ReferenceMap.WEAK, ReferenceMap.SOFT);
59
60
61 protected JRAbstractJavaCompiler(boolean needsSourceFiles)
62 {
63 super(needsSourceFiles);
64 }
65
66
67 protected JREvaluator loadEvaluator(Serializable compileData, String className) throws JRException
68 {
69 JREvaluator evaluator = null;
70
71 try
72 {
73 Class clazz = getClassFromCache(className);
74 if (clazz == null)
75 {
76 clazz = JRClassLoader.loadClassFromBytes(className, (byte[]) compileData);
77 putClassInCache(className, clazz);
78 }
79
80 classFromBytesRef.set(clazz);
82
83 evaluator = (JREvaluator) clazz.newInstance();
84 }
85 catch (Exception e)
86 {
87 throw new JRException("Error loading expression class : " + className, e);
88 }
89
90 return evaluator;
91 }
92
93
94 protected static Object classCacheKey()
95 {
96 ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
97 Object key = contextClassLoader == null ? CLASS_CACHE_NULL_KEY : contextClassLoader;
98 return key;
99 }
100
101
102 protected static synchronized Class getClassFromCache(String className)
103 {
104 Object key = classCacheKey();
105 Map contextMap = (Map ) classCache.get(key);
106 Class cachedClass = null;
107 if (contextMap != null)
108 {
109 cachedClass = (Class ) contextMap.get(className);
110 }
111 return cachedClass;
112 }
113
114
115 protected static synchronized void putClassInCache(String className, Class loadedClass)
116 {
117 Object key = classCacheKey();
118 Map contextMap = (Map ) classCache.get(key);
119 if (contextMap == null)
120 {
121 contextMap = new ReferenceMap(ReferenceMap.HARD, ReferenceMap.SOFT);
122 classCache.put(key, contextMap);
123 }
124 contextMap.put(className, loadedClass);
125 }
126 }
127 |
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Java API By Example, From Geeks To Geeks.