| 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.Constructor; |
| 18 | import java.lang.reflect.InvocationTargetException; |
| 19 | import java.util.HashMap; |
| 20 | import java.util.Map; |
| 21 | |
| 22 | import org.apache.commons.logging.Log; |
| 23 | |
| 24 | import net.sourceforge.hiveutils.service.ExceptionMapper; |
| 25 | import net.sourceforge.hiveutils.util.ClassMatcher; |
| 26 | |
| 27 | /** |
| 28 | * Default implementation of <code>ExceptionMapper</code>, based on a |
| 29 | * <code>ClassMatcher</code> to do the exception translation. |
| 30 | * <p> |
| 31 | * It can be instantiated directly by the <code>AdapterBuilderFactory</code> |
| 32 | * depending on the parameters specified in the module descriptor. |
| 33 | * |
| 34 | * @author Jean-Francois Poilpret |
| 35 | */ |
| 36 | public class DefaultExceptionMapper implements ExceptionMapper |
| 37 | { |
| 38 | /** |
| 39 | * Constructs the <code>ExceptionMapper</code> from the passed |
| 40 | * <code>ClassMatcher</code>. |
| 41 | * @param logger logger to be used for warnings |
| 42 | * @param matcher the matcher used to find how to translate thrown |
| 43 | * exceptions |
| 44 | */ |
| 45 | public DefaultExceptionMapper(Log logger, ClassMatcher matcher) |
| 46 | { |
| 47 | _logger = logger; |
| 48 | _matcher = matcher; |
| 49 | } |
| 50 | |
| 51 | public Throwable translate(Throwable t) |
| 52 | { |
| 53 | Class clazz = (Class) _matcher.get(t); |
| 54 | if (clazz != null) |
| 55 | { |
| 56 | return wrapThrowable(clazz, t); |
| 57 | } |
| 58 | else |
| 59 | { |
| 60 | return t; |
| 61 | } |
| 62 | } |
| 63 | |
| 64 | protected Throwable wrapThrowable(Class clazz, Throwable source) |
| 65 | { |
| 66 | Constructor[] ctors = getConstructors(clazz); |
| 67 | try |
| 68 | { |
| 69 | if (ctors[CTOR_ALL] != null) |
| 70 | { |
| 71 | return (Throwable) ctors[CTOR_ALL].newInstance( |
| 72 | new Object[] {source.getMessage(), source}); |
| 73 | } |
| 74 | if (ctors[CTOR_THROWABLE] != null) |
| 75 | { |
| 76 | return (Throwable) ctors[CTOR_THROWABLE].newInstance( |
| 77 | new Object[] {source}); |
| 78 | } |
| 79 | if (ctors[CTOR_STRING] != null) |
| 80 | { |
| 81 | return (Throwable) ctors[CTOR_STRING].newInstance( |
| 82 | new Object[] {source.getMessage()}); |
| 83 | } |
| 84 | return (Throwable) clazz.newInstance(); |
| 85 | } |
| 86 | catch (InstantiationException e) |
| 87 | { |
| 88 | _logger.warn( "Exception Mapper could not instantiate " + |
| 89 | clazz.getName(), e); |
| 90 | return source; |
| 91 | } |
| 92 | catch (IllegalAccessException e) |
| 93 | { |
| 94 | _logger.warn( "Exception Mapper could not instantiate " + |
| 95 | clazz.getName(), e); |
| 96 | return source; |
| 97 | } |
| 98 | catch (InvocationTargetException e) |
| 99 | { |
| 100 | _logger.warn( "Exception Mapper could not instantiate " + |
| 101 | clazz.getName(), e); |
| 102 | return source; |
| 103 | } |
| 104 | } |
| 105 | |
| 106 | static protected Constructor[] getConstructors(Class clazz) |
| 107 | { |
| 108 | Constructor[] ctors; |
| 109 | synchronized (_constructors) |
| 110 | { |
| 111 | ctors = _constructors.get(clazz); |
| 112 | } |
| 113 | if (ctors == null) |
| 114 | { |
| 115 | ctors = new Constructor[NUM_CTORS]; |
| 116 | |
| 117 | Constructor ctor; |
| 118 | int index; |
| 119 | |
| 120 | index = CTOR_ALL; |
| 121 | ctor = getConstructor(clazz, ARGS_ALL); |
| 122 | if (ctor == null) |
| 123 | { |
| 124 | index = CTOR_THROWABLE; |
| 125 | ctor = getConstructor(clazz, ARGS_THROWABLE); |
| 126 | } |
| 127 | if (ctor == null) |
| 128 | { |
| 129 | index = CTOR_STRING; |
| 130 | ctor = getConstructor(clazz, ARGS_STRING); |
| 131 | } |
| 132 | |
| 133 | // Only keep the first matching constructor |
| 134 | ctors[index] = ctor; |
| 135 | synchronized (_constructors) |
| 136 | { |
| 137 | _constructors.put(clazz, ctors); |
| 138 | } |
| 139 | } |
| 140 | return ctors; |
| 141 | } |
| 142 | |
| 143 | static protected Constructor getConstructor(Class clazz, Class[] args) |
| 144 | { |
| 145 | try |
| 146 | { |
| 147 | return clazz.getConstructor(args); |
| 148 | } |
| 149 | catch (NoSuchMethodException e) |
| 150 | { |
| 151 | return null; |
| 152 | } |
| 153 | } |
| 154 | |
| 155 | private final Log _logger; |
| 156 | private final ClassMatcher _matcher; |
| 157 | // map Class --> Constructor[4] |
| 158 | // gives the existing constructors for this class in the following order: |
| 159 | // 0 constructor(String, Throwable) |
| 160 | // 1 constructor(Throwable) |
| 161 | // 2 constructor(String) |
| 162 | // 3 default constructor |
| 163 | // if one constructor does not exist, its value is null |
| 164 | static private final Map<Class, Constructor[]> _constructors = |
| 165 | new HashMap<Class, Constructor[]>(); |
| 166 | |
| 167 | static final protected int CTOR_ALL = 0; |
| 168 | static final protected int CTOR_THROWABLE = 1; |
| 169 | static final protected int CTOR_STRING = 2; |
| 170 | static final protected int NUM_CTORS = 3; |
| 171 | |
| 172 | static final private Class[] ARGS_ALL = new Class[] { String.class, |
| 173 | Throwable.class}; |
| 174 | static final private Class[] ARGS_THROWABLE = new Class[] {Throwable.class}; |
| 175 | static final private Class[] ARGS_STRING = new Class[] {String.class}; |
| 176 | } |