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1
17 package org.alfresco.repo.policy;
18
19 import java.lang.reflect.InvocationHandler  ;
20 import java.lang.reflect.InvocationTargetException ;
21 import java.lang.reflect.Method ;
22 import java.lang.reflect.Proxy ;
23 import java.util.HashMap ;
24 import java.util.Map ;
25 import java.util.Stack ;
26
27 import org.alfresco.util.ParameterCheck;
28
29
30
39 public class JavaBehaviour implements Behaviour
40 {
41 private Object instance;
43
44 private String method;
46
47 private Map <Class , Object > proxies = new HashMap <Class , Object >();
49
50 private StackThreadLocal disabled = new StackThreadLocal();
52
53
54
60 public JavaBehaviour(Object instance, String method)
61 {
62 ParameterCheck.mandatory("Instance", instance);
63 ParameterCheck.mandatory("Method", method);
64 this.instance = instance;
65 this.method = method;
66 }
67
68
69
72 @SuppressWarnings ("unchecked")
73 public synchronized <T> T getInterface(Class <T> policy)
74 {
75 ParameterCheck.mandatory("Policy class", policy);
76 Object proxy = proxies.get(policy);
77 if (proxy == null)
78 {
79 InvocationHandler handler = getInvocationHandler(instance, method, policy);
80 proxy = Proxy.newProxyInstance(policy.getClassLoader(), new Class []{policy}, handler);
81 proxies.put(policy, proxy);
82 }
83 return (T)proxy;
84 }
85
86
89 public void disable()
90 {
91 Stack <Integer > stack = disabled.get();
92 stack.push(hashCode());
93 }
94
95
98 public void enable()
99 {
100 Stack <Integer > stack = disabled.get();
101 if (stack.peek().equals(hashCode()) == false)
102 {
103 throw new PolicyException("Cannot enable " + this.toString() + " at this time - mismatched with disable calls");
104 }
105 stack.pop();
106 }
107
108
111 public boolean isEnabled()
112 {
113 Stack <Integer > stack = disabled.get();
114 return stack.search(hashCode()) == -1;
115 }
116
117 @Override
118 public String toString()
119 {
120 return "Java method[class=" + instance.getClass().getName() + ", method=" + method + "]";
121 }
122
123
132 private <T> InvocationHandler getInvocationHandler(Object instance, String method, Class <T> policyIF)
133 {
134 Method [] policyIFMethods = policyIF.getMethods();
135 if (policyIFMethods.length != 1)
136 {
137 throw new PolicyException("Policy interface " + policyIF.getCanonicalName() + " must have only one method");
138 }
139
140 try
141 {
142 Class instanceClass = instance.getClass();
143 Method delegateMethod = instanceClass.getMethod(method, (Class [])policyIFMethods[0].getParameterTypes());
144 return new JavaMethodInvocationHandler(this, delegateMethod);
145 }
146 catch (NoSuchMethodException e)
147 {
148 throw new PolicyException("Method " + method + " not found or accessible on " + instance.getClass(), e);
149 }
150 }
151
152
153
158 private class StackThreadLocal extends ThreadLocal <Stack <Integer >>
159 {
160 @Override
161 protected Stack <Integer > initialValue()
162 {
163 return new Stack <Integer >();
164 }
165 }
166
167
168
173 private static class JavaMethodInvocationHandler implements InvocationHandler
174 {
175 private JavaBehaviour behaviour;
176 private Method delegateMethod;
177
178
184 private JavaMethodInvocationHandler(JavaBehaviour behaviour, Method delegateMethod)
185 {
186 this.behaviour = behaviour;
187 this.delegateMethod = delegateMethod;
188 }
189
190
193 public Object invoke(Object proxy, Method method, Object [] args) throws Throwable
194 {
195 if (method.getName().equals("toString"))
197 {
198 return toString();
199 }
200 else if (method.getName().equals("hashCode"))
201 {
202 return hashCode();
203 }
204 else if (method.getName().equals("equals"))
205 {
206 if (Proxy.isProxyClass(args[0].getClass()))
207 {
208 return equals(Proxy.getInvocationHandler(args[0]));
209 }
210 return false;
211 }
212
213 if (behaviour.isEnabled())
215 {
216 try
217 {
218 behaviour.disable();
219 return delegateMethod.invoke(behaviour.instance, args);
220 }
221 catch (InvocationTargetException e)
222 {
223 throw e.getTargetException();
224 }
225 finally
226 {
227 behaviour.enable();
228 }
229 }
230 return null;
231 }
232
233 @Override
234 public boolean equals(Object obj)
235 {
236 if (obj == this)
237 {
238 return true;
239 }
240 else if (obj == null || !(obj instanceof JavaMethodInvocationHandler))
241 {
242 return false;
243 }
244 JavaMethodInvocationHandler other = (JavaMethodInvocationHandler)obj;
245 return behaviour.instance.equals(other.behaviour.instance) && delegateMethod.equals(other.delegateMethod);
246 }
247
248 @Override
249 public int hashCode()
250 {
251 return 37 * behaviour.instance.hashCode() + delegateMethod.hashCode();
252 }
253
254 @Override
255 public String toString()
256 {
257 return "JavaBehaviour[instance=" + behaviour.instance.hashCode() + ", method=" + delegateMethod.toString() + "]";
258 }
259 }
260
261 }
262 |
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