001 /** 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 package org.apache.xbean.spring.context.impl; 018 019 import org.springframework.beans.BeansException; 020 import org.springframework.beans.FatalBeanException; 021 import org.springframework.beans.MutablePropertyValues; 022 import org.springframework.beans.PropertyValue; 023 import org.springframework.beans.factory.FactoryBean; 024 import org.springframework.beans.factory.config.BeanDefinitionHolder; 025 import org.springframework.beans.factory.config.ConstructorArgumentValues; 026 import org.springframework.beans.factory.support.AbstractBeanDefinition; 027 028 import java.lang.reflect.Constructor; 029 import java.lang.reflect.Method; 030 import java.util.ArrayList; 031 import java.util.Arrays; 032 import java.util.Collections; 033 import java.util.Comparator; 034 import java.util.HashMap; 035 import java.util.HashSet; 036 import java.util.Iterator; 037 import java.util.LinkedList; 038 import java.util.List; 039 import java.util.Map; 040 import java.util.Set; 041 042 /** 043 * NamedConstructorArgs is a BeanFactoryPostProcessor that converts property declarations into indexed constructor args 044 * based on the the constructor parameter names annotation. This process first selects a constructor and then fills in 045 * the constructor arguments from the properties defined in the bean definition. If a property is not defined in the 046 * bean definition, first the defaultValues map is checked for a value and if a value is not present a Java default 047 * value is provided for the constructor argument (e.g. numbers are assigned 0 and objects are assigned null). 048 * 049 * @author Dain Sundstrom 050 * @version $Id$ 051 * @since 2.0 052 */ 053 public class NamedConstructorArgs { 054 private Map defaultValues = new HashMap(); 055 056 /** 057 * Gets the default values that are assigned to constructor arguments without a defined value. 058 * @return the default values that are assigned to constructor arguments without a defined value 059 */ 060 public List getDefaultValues() { 061 List values = new LinkedList(); 062 for (Iterator iterator = defaultValues.entrySet().iterator(); iterator.hasNext();) { 063 Map.Entry entry = (Map.Entry) iterator.next(); 064 PropertyKey key = (PropertyKey) entry.getKey(); 065 Object value = entry.getValue(); 066 values.add(new DefaultProperty(key.name, key.type, value)); 067 } 068 return values; 069 } 070 071 /** 072 * Sets the default values that are assigned to constructor arguments without a defined value. 073 * @param defaultValues the values that are assigned to constructor arguments without a defined value 074 */ 075 public void setDefaultValues(List defaultValues) { 076 this.defaultValues.clear(); 077 for (Iterator iterator = defaultValues.iterator(); iterator.hasNext();) { 078 addDefaultValue((DefaultProperty) iterator.next()); 079 } 080 } 081 082 /** 083 * Adds a default value for a property with the specified name and type. 084 * @param name the name of the property 085 * @param type the type of the property 086 * @param value the default value for a property with the specified name and type 087 */ 088 public void addDefaultValue(String name, Class type, Object value) { 089 defaultValues.put(new PropertyKey(name, type), value); 090 } 091 092 /** 093 * Adds a defautl value for a property. 094 * @param defaultProperty the default property information 095 */ 096 private void addDefaultValue(DefaultProperty defaultProperty) { 097 defaultValues.put(new PropertyKey(defaultProperty.getName(), defaultProperty.getType()), defaultProperty.getValue()); 098 } 099 100 public void processParameters(BeanDefinitionHolder definitionHolder, MappingMetaData metadata) throws BeansException { 101 // this only works if we have an abstsract bean definition 102 if (!(definitionHolder.getBeanDefinition() instanceof AbstractBeanDefinition)) { 103 return; 104 } 105 106 AbstractBeanDefinition beanDefinition = (AbstractBeanDefinition) definitionHolder.getBeanDefinition(); 107 ConstructorArgumentValues constructorArgumentValues = beanDefinition.getConstructorArgumentValues(); 108 109 // if this bean already has constructor arguments defined, don't mess with them 110 if (constructorArgumentValues.getArgumentCount() > 0) { 111 return; 112 } 113 114 // try to get a list of constructor arg names to use 115 ConstructionInfo constructionInfo = selectConstructionMethod(beanDefinition, metadata); 116 if (constructionInfo == null) { 117 return; 118 } 119 120 // remove each named property and add an indexed constructor arg 121 MutablePropertyValues propertyValues = beanDefinition.getPropertyValues(); 122 String[] parameterNames = constructionInfo.parameterNames; 123 Class[] parameterTypes = constructionInfo.parameterTypes; 124 for (int i = 0; i < parameterNames.length; i++) { 125 String parameterName = parameterNames[i]; 126 Class parameterType = parameterTypes[i]; 127 128 PropertyValue propertyValue = propertyValues.getPropertyValue(parameterName); 129 if (propertyValue != null) { 130 propertyValues.removePropertyValue(parameterName); 131 constructorArgumentValues.addIndexedArgumentValue(i, propertyValue.getValue(), parameterType.getName()); 132 } else { 133 Object defaultValue = defaultValues.get(new PropertyKey(parameterName, parameterType)); 134 if (defaultValue == null) { 135 defaultValue = DEFAULT_VALUE.get(parameterType); 136 } 137 if (defaultValue instanceof FactoryBean) { 138 try { 139 defaultValue = ((FactoryBean)defaultValue).getObject(); 140 } catch (Exception e) { 141 throw new FatalBeanException("Unable to get object value from bean factory", e); 142 } 143 } 144 constructorArgumentValues.addIndexedArgumentValue(i, defaultValue, parameterType.getName()); 145 } 146 } 147 148 // todo set any usable default values on the bean definition 149 } 150 151 private ConstructionInfo selectConstructionMethod(AbstractBeanDefinition beanDefinition, MappingMetaData metadata) { 152 Class beanClass = beanDefinition.getBeanClass(); 153 154 // get a set containing the names of the defined properties 155 Set definedProperties = new HashSet(); 156 PropertyValue[] values = beanDefinition.getPropertyValues().getPropertyValues(); 157 for (int i = 0; i < values.length; i++) { 158 definedProperties.add(values[i].getName()); 159 } 160 161 // first check for a factory method 162 if (beanDefinition.getFactoryMethodName() != null) { 163 return selectFactory(beanClass, beanDefinition, metadata, definedProperties); 164 } else { 165 return selectConstructor(beanClass, metadata, definedProperties); 166 } 167 } 168 169 private ConstructionInfo selectFactory(Class beanClass, AbstractBeanDefinition beanDefinition, MappingMetaData metadata, Set definedProperties) { 170 String factoryMethodName = beanDefinition.getFactoryMethodName(); 171 172 // get the factory methods sorted by longest arg length first 173 Method[] methods = beanClass.getMethods(); 174 List factoryMethods = new ArrayList(methods.length); 175 for (int i = 0; i < methods.length; i++) { 176 Method method = methods[i]; 177 if (method.getName().equals(factoryMethodName)) { 178 factoryMethods.add(method); 179 } 180 } 181 182 Collections.sort(factoryMethods, new ArgLengthComparator()); 183 184 // if a factory method has been annotated as the default constructor we always use that constructor 185 for (Iterator iterator = factoryMethods.iterator(); iterator.hasNext();) { 186 Method factoryMethod = (Method) iterator.next(); 187 188 if (metadata.isDefaultFactoryMethod(beanClass, factoryMethod)) { 189 return new ConstructionInfo(beanClass, factoryMethod, metadata); 190 } 191 } 192 193 // try to find a constructor for which we have all of the properties defined 194 for (Iterator iterator = factoryMethods.iterator(); iterator.hasNext();) { 195 Method factoryMethod = (Method) iterator.next(); 196 ConstructionInfo constructionInfo = new ConstructionInfo(beanClass, factoryMethod, metadata); 197 if (isUsableConstructor(constructionInfo, definedProperties)) { 198 return constructionInfo; 199 } 200 } 201 return null; 202 } 203 204 private ConstructionInfo selectConstructor(Class beanClass, MappingMetaData metadata, Set definedProperties) { 205 // get the constructors sorted by longest arg length first 206 List constructors = new ArrayList(Arrays.asList(beanClass.getConstructors())); 207 Collections.sort(constructors, new ArgLengthComparator()); 208 209 // if a constructor has been annotated as the default constructor we always use that constructor 210 for (Iterator iterator = constructors.iterator(); iterator.hasNext();) { 211 Constructor constructor = (Constructor) iterator.next(); 212 213 if (metadata.isDefaultConstructor(constructor)) { 214 return new ConstructionInfo(constructor, metadata); 215 } 216 } 217 218 // try to find a constructor for which we have all of the properties defined 219 for (Iterator iterator = constructors.iterator(); iterator.hasNext();) { 220 Constructor constructor = (Constructor) iterator.next(); 221 ConstructionInfo constructionInfo = new ConstructionInfo(constructor, metadata); 222 if (isUsableConstructor(constructionInfo, definedProperties)) { 223 return constructionInfo; 224 } 225 } 226 return null; 227 } 228 229 private boolean isUsableConstructor(ConstructionInfo constructionInfo, Set definedProperties) { 230 // if we don't have parameter names this is not the constructor we are looking for 231 String[] parameterNames = constructionInfo.parameterNames; 232 if (parameterNames == null) { 233 return false; 234 } 235 236 Class[] parameterTypes = constructionInfo.parameterTypes; 237 for (int i = 0; i < parameterNames.length; i++) { 238 String parameterName = parameterNames[i]; 239 Class parameterType = parameterTypes[i]; 240 241 // can we satify this property using a defined property or default property 242 if (!definedProperties.contains(parameterName) && !defaultValues.containsKey(new PropertyKey(parameterName, parameterType))) { 243 return false; 244 } 245 } 246 247 return true; 248 } 249 250 private class ConstructionInfo { 251 private final Class[] parameterTypes; 252 private final String[] parameterNames; 253 254 public ConstructionInfo(Constructor constructor, MappingMetaData metadata) { 255 this.parameterTypes = constructor.getParameterTypes(); 256 String[] names = metadata.getParameterNames(constructor); 257 258 // verify that we have enough parameter names 259 int expectedParameterCount = parameterTypes.length; 260 if (names != null && names.length != expectedParameterCount) { 261 throw new FatalBeanException("Excpected " + expectedParameterCount + " parameter names for constructor but only got " + 262 names.length + ": " + constructor.toString()); 263 } 264 if (expectedParameterCount == 0) { 265 names = new String[0]; 266 } 267 268 this.parameterNames = names; 269 } 270 271 public ConstructionInfo(Class beanClass, Method factoryMethod, MappingMetaData metadata) { 272 this.parameterTypes = factoryMethod.getParameterTypes(); 273 274 String[] names = metadata.getParameterNames(beanClass, factoryMethod); 275 276 // verify that we have enough parameter names 277 int expectedParameterCount = parameterTypes.length; 278 if (names != null && names.length != expectedParameterCount) { 279 throw new FatalBeanException("Excpected " + expectedParameterCount + " parameter names for factory method but only got " + 280 names.length + ": " + factoryMethod.toString()); 281 } 282 if (expectedParameterCount == 0) { 283 names = new String[0]; 284 } 285 286 this.parameterNames = names; 287 } 288 } 289 290 private static class ArgLengthComparator implements Comparator { 291 public int compare(Object o1, Object o2) { 292 return getArgLength(o2) - getArgLength(o1); 293 } 294 295 private int getArgLength(Object object) { 296 if (object instanceof Method) { 297 return ((Method) object).getParameterTypes().length; 298 } else { 299 return ((Constructor) object).getParameterTypes().length; 300 } 301 } 302 } 303 304 private static class PropertyKey { 305 private final String name; 306 private final Class type; 307 308 public PropertyKey(String name, Class type) { 309 this.name = name; 310 this.type = type; 311 } 312 313 public boolean equals(Object object) { 314 if (!(object instanceof PropertyKey)) { 315 return false; 316 } 317 318 PropertyKey defaultProperty = (PropertyKey) object; 319 return name.equals(defaultProperty.name) && type.equals(type); 320 } 321 322 public int hashCode() { 323 int result = 17; 324 result = 37 * result + name.hashCode(); 325 result = 37 * result + type.hashCode(); 326 return result; 327 } 328 329 public String toString() { 330 return "[" + name + " " + type + "]"; 331 } 332 } 333 334 private static final Map DEFAULT_VALUE; 335 static { 336 Map temp = new HashMap(); 337 temp.put(Boolean.TYPE, Boolean.FALSE); 338 temp.put(Byte.TYPE, new Byte((byte) 0)); 339 temp.put(Character.TYPE, new Character((char) 0)); 340 temp.put(Short.TYPE, new Short((short) 0)); 341 temp.put(Integer.TYPE, new Integer(0)); 342 temp.put(Long.TYPE, new Long(0)); 343 temp.put(Float.TYPE, new Float(0)); 344 temp.put(Double.TYPE, new Double(0)); 345 346 DEFAULT_VALUE = Collections.unmodifiableMap(temp); 347 } 348 }