| 1 | // Copyright 2004-2007 Jean-Francois Poilpret |
| 2 | // |
| 3 | // Licensed under the Apache License, Version 2.0 (the "License"); |
| 4 | // you may not use this file except in compliance with the License. |
| 5 | // You may obtain a copy of the License at |
| 6 | // |
| 7 | // http://www.apache.org/licenses/LICENSE-2.0 |
| 8 | // |
| 9 | // Unless required by applicable law or agreed to in writing, software |
| 10 | // distributed under the License is distributed on an "AS IS" BASIS, |
| 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 12 | // See the License for the specific language governing permissions and |
| 13 | // limitations under the License. |
| 14 | |
| 15 | package net.sourceforge.hiveutils.service.impl; |
| 16 | |
| 17 | import java.lang.reflect.InvocationHandler; |
| 18 | import java.lang.reflect.InvocationTargetException; |
| 19 | import java.lang.reflect.Method; |
| 20 | import java.lang.reflect.Proxy; |
| 21 | import java.util.Iterator; |
| 22 | import java.util.List; |
| 23 | |
| 24 | import org.apache.commons.logging.Log; |
| 25 | |
| 26 | import org.apache.hivemind.InterceptorStack; |
| 27 | import org.apache.hivemind.ServiceInterceptorFactory; |
| 28 | import org.apache.hivemind.internal.Module; |
| 29 | |
| 30 | import net.sourceforge.hiveutils.service.ExceptionMapper; |
| 31 | import net.sourceforge.hiveutils.util.ClassMatcher; |
| 32 | |
| 33 | /** |
| 34 | * This service creates service interceptors that allow to map an exception to |
| 35 | * another. |
| 36 | * |
| 37 | * @author Jean-Francois Poilpret |
| 38 | */ |
| 39 | public class ExceptionMappingInterceptorFactory implements ServiceInterceptorFactory |
| 40 | { |
| 41 | public void createInterceptor(InterceptorStack stack, Module invokingMod, List parameters) |
| 42 | { |
| 43 | Log logger = stack.getServiceLog(); |
| 44 | stack.push(Proxy.newProxyInstance( |
| 45 | invokingMod.getClassResolver().getClassLoader(), |
| 46 | new Class[] {stack.getServiceInterface()}, |
| 47 | new Interceptor(logger, stack.peek(), parameters))); |
| 48 | } |
| 49 | |
| 50 | static private class Interceptor implements InvocationHandler |
| 51 | { |
| 52 | public Interceptor(Log logger, Object target, List parameters) |
| 53 | { |
| 54 | _logger = logger; |
| 55 | _target = target; |
| 56 | _mapper = null; |
| 57 | |
| 58 | // matcher will contain all exception mappings contained in parameters |
| 59 | ClassMatcher matcher = new ClassMatcher(); |
| 60 | boolean hasMapping = configureMapper(parameters, matcher); |
| 61 | |
| 62 | if (_mapper == null && !hasMapping) |
| 63 | { |
| 64 | // Log warning (we can go on but all exceptions will be passed |
| 65 | // "as is" |
| 66 | _logger.warn("No exception mapping defined"); |
| 67 | } |
| 68 | // Create the exception mapper from parameters and instantiate |
| 69 | // the exception-mapping proxy around the service |
| 70 | if (_mapper == null) |
| 71 | { |
| 72 | _mapper = new DefaultExceptionMapper(logger, matcher); |
| 73 | } |
| 74 | } |
| 75 | |
| 76 | private boolean configureMapper(List parameters, ClassMatcher matcher) |
| 77 | { |
| 78 | // matcher will contain all exception mappings contained in parameters |
| 79 | boolean hasMapping = false; |
| 80 | Iterator i = parameters.iterator(); |
| 81 | while (i.hasNext()) |
| 82 | { |
| 83 | Object param = i.next(); |
| 84 | if (param instanceof ExceptionMappingContribution) |
| 85 | { |
| 86 | if (_mapper == null) |
| 87 | { |
| 88 | ExceptionMappingContribution map = |
| 89 | (ExceptionMappingContribution) param; |
| 90 | // Check that from and to are Throwable |
| 91 | boolean classesAreExceptions = true; |
| 92 | if (!Throwable.class.isAssignableFrom(map.getFrom())) |
| 93 | { |
| 94 | // This is only a warning because we do not account for them |
| 95 | _logger.warn(map.getFrom().getName() + " is not a Throwable"); |
| 96 | classesAreExceptions = false; |
| 97 | } |
| 98 | if (!Throwable.class.isAssignableFrom(map.getTo())) |
| 99 | { |
| 100 | // This is only a warning because we do not account for them |
| 101 | _logger.warn(map.getTo().getName() + " is not a Throwable"); |
| 102 | classesAreExceptions = false; |
| 103 | } |
| 104 | if (classesAreExceptions) |
| 105 | { |
| 106 | hasMapping = true; |
| 107 | matcher.put(map.getFrom(), map.getTo()); |
| 108 | } |
| 109 | } |
| 110 | else |
| 111 | { |
| 112 | // Log warning, but don't account for this "exception-mapping" tag |
| 113 | _logger.warn("<exception-mapping> not accounted for because it " + |
| 114 | "conflicts with a <exception-mapper> tag"); |
| 115 | } |
| 116 | } |
| 117 | else if (param instanceof ExceptionMapperContribution) |
| 118 | { |
| 119 | if (_mapper == null && !hasMapping) |
| 120 | { |
| 121 | ExceptionMapperContribution map = |
| 122 | (ExceptionMapperContribution) param; |
| 123 | _mapper = map.getMapper(); |
| 124 | } |
| 125 | else |
| 126 | { |
| 127 | // Log warning, but don't account for this "exception-mapper" tag |
| 128 | _logger.warn("<exception-mapper> not accounted for because it " + |
| 129 | "conflicts with another tag"); |
| 130 | } |
| 131 | } |
| 132 | } |
| 133 | return hasMapping; |
| 134 | } |
| 135 | |
| 136 | //CSOFF: IllegalThrowsCheck |
| 137 | //CSOFF: IllegalCatchCheck |
| 138 | public Object invoke(Object proxy, Method method, Object[] args) |
| 139 | throws Throwable |
| 140 | { |
| 141 | try |
| 142 | { |
| 143 | return method.invoke(_target, args); |
| 144 | } |
| 145 | catch (InvocationTargetException e) |
| 146 | { |
| 147 | throw _mapper.translate(e.getTargetException()); |
| 148 | } |
| 149 | catch (Throwable t) |
| 150 | { |
| 151 | throw _mapper.translate(t); |
| 152 | } |
| 153 | } |
| 154 | //CSON: IllegalCatchCheck |
| 155 | //CSON: IllegalThrowsCheck |
| 156 | |
| 157 | private final Log _logger; |
| 158 | private final Object _target; |
| 159 | private ExceptionMapper _mapper; |
| 160 | } |
| 161 | } |