Add an implementation of Annotation

git-svn-id: http://anonsvn.jboss.org/repos/weld/ri/trunk@2428 1c488680-804c-0410-94cd-c6b725194a0e

impl/src/main/java/org/jboss/webbeans/util/reflection/AnnotationImpl.java

@@ -0,0 +1,125 @@
+/*
+* JBoss, Home of Professional Open Source
+* Copyright 2008, Red Hat Middleware LLC, and individual contributors
+* by the @authors tag. See the copyright.txt in the distribution for a
+* full listing of individual contributors.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+* http://www.apache.org/licenses/LICENSE-2.0
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,  
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+package org.jboss.webbeans.util.reflection;
+
+import java.lang.annotation.Annotation;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+
+import javax.inject.ExecutionException;
+
+
+/**
+ * Supports instantiation of annotation type instances.
+ * 
+ * @author Pete Muir
+ * @author Gavin King
+ * 
+ *  @param <T>
+ *            the annotation type
+ */
+public class AnnotationImpl<T extends Annotation> implements Annotation
+{
+
+   private final Class<T> annotationType;
+   private final Method[] members;
+
+   public AnnotationImpl(Class<T> annotationType, Method[] members)
+   {
+      this.annotationType = annotationType;
+      this.members = members;
+   }
+
+   public Class<? extends Annotation> annotationType()
+   {
+      return annotationType;
+   }
+
+   @Override
+   public String toString()
+   {
+     String string = "@" + annotationType().getName() + "(";
+     for (int i = 0; i < members.length; i++)
+     {
+        string += members[i].getName() + "=";
+        string += invoke(members[i], this);
+        if (i < members.length - 1)
+        {
+           string += ",";
+        }
+     }
+     return string + ")";
+   }
+
+   @Override
+   public boolean equals(Object other)
+   {
+      if (other instanceof Annotation)
+      {
+         Annotation that = (Annotation) other;
+         if (this.annotationType().equals(that.annotationType()))
+         {
+            for (Method member : members)
+            {
+               Object thisValue = invoke(member, this);
+               Object thatValue = invoke(member, that);
+               if (!thisValue.equals(thatValue))
+               {
+                  return false;
+               }
+            }
+            return true;
+         }
+      }
+      return false;
+   }
+
+   @Override
+   public int hashCode()
+   {
+      int hashCode = 0;
+      for (Method member : members)
+      {
+         int memberNameHashCode = 127 * member.getName().hashCode();
+         int memberValueHashCode = invoke(member, this).hashCode();
+         hashCode += memberNameHashCode ^ memberValueHashCode;
+      }       
+      return hashCode;
+   }
+
+   private static Object invoke(Method method, Object instance)
+   {
+      try
+      {
+         method.setAccessible(true);
+         return method.invoke(instance);
+      }
+      catch (IllegalArgumentException e)
+      {
+         throw new ExecutionException("Error checking value of member method " + method.getName() + " on " + method.getDeclaringClass(), e);
+      }
+      catch (IllegalAccessException e)
+      {
+         throw new ExecutionException("Error checking value of member method " + method.getName() + " on " + method.getDeclaringClass(), e);
+      }
+      catch (InvocationTargetException e)
+      {
+         throw new ExecutionException("Error checking value of member method " + method.getName() + " on " + method.getDeclaringClass(), e);
+      }
+   }
+}