Coverage Report - org.apache.commons.configuration.beanutils.BeanHelper
 
Classes in this File Line Coverage Branch Coverage Complexity
BeanHelper
88%
81/92
92%
37/40
3,471
 
 1  
 /*
 2  
  * Licensed to the Apache Software Foundation (ASF) under one or more
 3  
  * contributor license agreements.  See the NOTICE file distributed with
 4  
  * this work for additional information regarding copyright ownership.
 5  
  * The ASF licenses this file to You under the Apache License, Version 2.0
 6  
  * (the "License"); you may not use this file except in compliance with
 7  
  * the License.  You may obtain a copy of the License at
 8  
  *
 9  
  *     http://www.apache.org/licenses/LICENSE-2.0
 10  
  *
 11  
  * Unless required by applicable law or agreed to in writing, software
 12  
  * distributed under the License is distributed on an "AS IS" BASIS,
 13  
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 14  
  * See the License for the specific language governing permissions and
 15  
  * limitations under the License.
 16  
  */
 17  
 package org.apache.commons.configuration.beanutils;
 18  
 
 19  
 import java.beans.PropertyDescriptor;
 20  
 import java.lang.reflect.InvocationTargetException;
 21  
 import java.util.Collection;
 22  
 import java.util.Collections;
 23  
 import java.util.HashMap;
 24  
 import java.util.List;
 25  
 import java.util.Map;
 26  
 import java.util.Set;
 27  
 
 28  
 import org.apache.commons.beanutils.BeanUtils;
 29  
 import org.apache.commons.beanutils.PropertyUtils;
 30  
 import org.apache.commons.configuration.ConfigurationRuntimeException;
 31  
 import org.apache.commons.lang.ClassUtils;
 32  
 
 33  
 /**
 34  
  * <p>
 35  
  * A helper class for creating bean instances that are defined in configuration
 36  
  * files.
 37  
  * </p>
 38  
  * <p>
 39  
  * This class provides static utility methods related to bean creation
 40  
  * operations. These methods simplify such operations because a client need not
 41  
  * deal with all involved interfaces. Usually, if a bean declaration has already
 42  
  * been obtained, a single method call is necessary to create a new bean
 43  
  * instance.
 44  
  * </p>
 45  
  * <p>
 46  
  * This class also supports the registration of custom bean factories.
 47  
  * Implementations of the {@link BeanFactory} interface can be
 48  
  * registered under a symbolic name using the {@code registerBeanFactory()}
 49  
  * method. In the configuration file the name of the bean factory can be
 50  
  * specified in the bean declaration. Then this factory will be used to create
 51  
  * the bean.
 52  
  * </p>
 53  
  *
 54  
  * @since 1.3
 55  
  * @author <a
 56  
  * href="http://commons.apache.org/configuration/team-list.html">Commons
 57  
  * Configuration team</a>
 58  
  * @version $Id: BeanHelper.java 1366932 2012-07-29 20:06:31Z oheger $
 59  
  */
 60  
 public final class BeanHelper
 61  
 {
 62  
     /** Stores a map with the registered bean factories. */
 63  1
     private static final Map<String, BeanFactory> BEAN_FACTORIES = Collections
 64  
             .synchronizedMap(new HashMap<String, BeanFactory>());
 65  
 
 66  
     /**
 67  
      * Stores the default bean factory, which will be used if no other factory
 68  
      * is provided.
 69  
      */
 70  1
     private static BeanFactory defaultBeanFactory = DefaultBeanFactory.INSTANCE;
 71  
 
 72  
     /**
 73  
      * Private constructor, so no instances can be created.
 74  
      */
 75  
     private BeanHelper()
 76  0
     {
 77  0
     }
 78  
 
 79  
     /**
 80  
      * Register a bean factory under a symbolic name. This factory object can
 81  
      * then be specified in bean declarations with the effect that this factory
 82  
      * will be used to obtain an instance for the corresponding bean
 83  
      * declaration.
 84  
      *
 85  
      * @param name the name of the factory
 86  
      * @param factory the factory to be registered
 87  
      */
 88  
     public static void registerBeanFactory(String name, BeanFactory factory)
 89  
     {
 90  12
         if (name == null)
 91  
         {
 92  1
             throw new IllegalArgumentException(
 93  
                     "Name for bean factory must not be null!");
 94  
         }
 95  11
         if (factory == null)
 96  
         {
 97  1
             throw new IllegalArgumentException("Bean factory must not be null!");
 98  
         }
 99  
 
 100  10
         BEAN_FACTORIES.put(name, factory);
 101  10
     }
 102  
 
 103  
     /**
 104  
      * Deregisters the bean factory with the given name. After that this factory
 105  
      * cannot be used any longer.
 106  
      *
 107  
      * @param name the name of the factory to be deregistered
 108  
      * @return the factory that was registered under this name; <b>null</b> if
 109  
      * there was no such factory
 110  
      */
 111  
     public static BeanFactory deregisterBeanFactory(String name)
 112  
     {
 113  11
         return BEAN_FACTORIES.remove(name);
 114  
     }
 115  
 
 116  
     /**
 117  
      * Returns a set with the names of all currently registered bean factories.
 118  
      *
 119  
      * @return a set with the names of the registered bean factories
 120  
      */
 121  
     public static Set<String> registeredFactoryNames()
 122  
     {
 123  215
         return BEAN_FACTORIES.keySet();
 124  
     }
 125  
 
 126  
     /**
 127  
      * Returns the default bean factory.
 128  
      *
 129  
      * @return the default bean factory
 130  
      */
 131  
     public static BeanFactory getDefaultBeanFactory()
 132  
     {
 133  420
         return defaultBeanFactory;
 134  
     }
 135  
 
 136  
     /**
 137  
      * Sets the default bean factory. This factory will be used for all create
 138  
      * operations, for which no special factory is provided in the bean
 139  
      * declaration.
 140  
      *
 141  
      * @param factory the default bean factory (must not be <b>null</b>)
 142  
      */
 143  
     public static void setDefaultBeanFactory(BeanFactory factory)
 144  
     {
 145  22
         if (factory == null)
 146  
         {
 147  1
             throw new IllegalArgumentException(
 148  
                     "Default bean factory must not be null!");
 149  
         }
 150  21
         defaultBeanFactory = factory;
 151  21
     }
 152  
 
 153  
     /**
 154  
      * Initializes the passed in bean. This method will obtain all the bean's
 155  
      * properties that are defined in the passed in bean declaration. These
 156  
      * properties will be set on the bean. If necessary, further beans will be
 157  
      * created recursively.
 158  
      *
 159  
      * @param bean the bean to be initialized
 160  
      * @param data the bean declaration
 161  
      * @throws ConfigurationRuntimeException if a property cannot be set
 162  
      */
 163  
     public static void initBean(Object bean, BeanDeclaration data)
 164  
             throws ConfigurationRuntimeException
 165  
     {
 166  670
         initBeanProperties(bean, data);
 167  
 
 168  669
         Map<String, Object> nestedBeans = data.getNestedBeanDeclarations();
 169  669
         if (nestedBeans != null)
 170  
         {
 171  661
             if (bean instanceof Collection)
 172  
             {
 173  
                 // This is safe because the collection stores the values of the
 174  
                 // nested beans.
 175  
                 @SuppressWarnings("unchecked")
 176  1
                 Collection<Object> coll = (Collection<Object>) bean;
 177  1
                 if (nestedBeans.size() == 1)
 178  
                 {
 179  1
                     Map.Entry<String, Object> e = nestedBeans.entrySet().iterator().next();
 180  1
                     String propName = e.getKey();
 181  1
                     Class<?> defaultClass = getDefaultClass(bean, propName);
 182  1
                     if (e.getValue() instanceof List)
 183  
                     {
 184  
                         // This is safe, provided that the bean declaration is implemented
 185  
                         // correctly.
 186  
                         @SuppressWarnings("unchecked")
 187  1
                         List<BeanDeclaration> decls = (List<BeanDeclaration>) e.getValue();
 188  1
                         for (BeanDeclaration decl : decls)
 189  
                         {
 190  2
                             coll.add(createBean(decl, defaultClass));
 191  
                         }
 192  1
                     }
 193  
                     else
 194  
                     {
 195  0
                         BeanDeclaration decl = (BeanDeclaration) e.getValue();
 196  0
                         coll.add(createBean(decl, defaultClass));
 197  
                     }
 198  
                 }
 199  1
             }
 200  
             else
 201  
             {
 202  660
                 for (Map.Entry<String, Object> e : nestedBeans.entrySet())
 203  
                 {
 204  232
                     String propName = e.getKey();
 205  232
                     Class<?> defaultClass = getDefaultClass(bean, propName);
 206  232
                     initProperty(bean, propName, createBean(
 207  
                         (BeanDeclaration) e.getValue(), defaultClass));
 208  232
                 }
 209  
             }
 210  
         }
 211  669
     }
 212  
 
 213  
     /**
 214  
      * Initializes the beans properties.
 215  
      *
 216  
      * @param bean the bean to be initialized
 217  
      * @param data the bean declaration
 218  
      * @throws ConfigurationRuntimeException if a property cannot be set
 219  
      */
 220  
     public static void initBeanProperties(Object bean, BeanDeclaration data)
 221  
             throws ConfigurationRuntimeException
 222  
     {
 223  670
         Map<String, Object> properties = data.getBeanProperties();
 224  670
         if (properties != null)
 225  
         {
 226  669
             for (Map.Entry<String, Object> e : properties.entrySet())
 227  
             {
 228  699
                 String propName = e.getKey();
 229  699
                 initProperty(bean, propName, e.getValue());
 230  698
             }
 231  
         }
 232  669
     }
 233  
 
 234  
     /**
 235  
      * Return the Class of the property if it can be determined.
 236  
      * @param bean The bean containing the property.
 237  
      * @param propName The name of the property.
 238  
      * @return The class associated with the property or null.
 239  
      */
 240  
     private static Class<?> getDefaultClass(Object bean, String propName)
 241  
     {
 242  
         try
 243  
         {
 244  233
             PropertyDescriptor desc = PropertyUtils.getPropertyDescriptor(bean, propName);
 245  233
             if (desc == null)
 246  
             {
 247  0
                 return null;
 248  
             }
 249  233
             return desc.getPropertyType();
 250  
         }
 251  0
         catch (Exception ex)
 252  
         {
 253  0
             return null;
 254  
         }
 255  
     }
 256  
 
 257  
     /**
 258  
      * Sets a property on the given bean using Common Beanutils.
 259  
      *
 260  
      * @param bean the bean
 261  
      * @param propName the name of the property
 262  
      * @param value the property's value
 263  
      * @throws ConfigurationRuntimeException if the property is not writeable or
 264  
      * an error occurred
 265  
      */
 266  
     private static void initProperty(Object bean, String propName, Object value)
 267  
             throws ConfigurationRuntimeException
 268  
     {
 269  986
         if (!PropertyUtils.isWriteable(bean, propName))
 270  
         {
 271  1
             throw new ConfigurationRuntimeException("Property " + propName
 272  
                     + " cannot be set on " + bean.getClass().getName());
 273  
         }
 274  
 
 275  
         try
 276  
         {
 277  985
             BeanUtils.setProperty(bean, propName, value);
 278  
         }
 279  0
         catch (IllegalAccessException iaex)
 280  
         {
 281  0
             throw new ConfigurationRuntimeException(iaex);
 282  
         }
 283  0
         catch (InvocationTargetException itex)
 284  
         {
 285  0
             throw new ConfigurationRuntimeException(itex);
 286  985
         }
 287  985
     }
 288  
 
 289  
     /**
 290  
      * Set a property on the bean only if the property exists
 291  
      *
 292  
      * @param bean the bean
 293  
      * @param propName the name of the property
 294  
      * @param value the property's value
 295  
      * @throws ConfigurationRuntimeException if the property is not writeable or
 296  
      *         an error occurred
 297  
      */
 298  
     public static void setProperty(Object bean, String propName, Object value)
 299  
     {
 300  61
         if (PropertyUtils.isWriteable(bean, propName))
 301  
         {
 302  55
             initProperty(bean, propName, value);
 303  
         }
 304  61
     }
 305  
 
 306  
     /**
 307  
      * The main method for creating and initializing beans from a configuration.
 308  
      * This method will return an initialized instance of the bean class
 309  
      * specified in the passed in bean declaration. If this declaration does not
 310  
      * contain the class of the bean, the passed in default class will be used.
 311  
      * From the bean declaration the factory to be used for creating the bean is
 312  
      * queried. The declaration may here return <b>null</b>, then a default
 313  
      * factory is used. This factory is then invoked to perform the create
 314  
      * operation.
 315  
      *
 316  
      * @param data the bean declaration
 317  
      * @param defaultClass the default class to use
 318  
      * @param param an additional parameter that will be passed to the bean
 319  
      * factory; some factories may support parameters and behave different
 320  
      * depending on the value passed in here
 321  
      * @return the new bean
 322  
      * @throws ConfigurationRuntimeException if an error occurs
 323  
      */
 324  
     public static Object createBean(BeanDeclaration data, Class<?> defaultClass,
 325  
             Object param) throws ConfigurationRuntimeException
 326  
     {
 327  669
         if (data == null)
 328  
         {
 329  1
             throw new IllegalArgumentException(
 330  
                     "Bean declaration must not be null!");
 331  
         }
 332  
 
 333  668
         BeanFactory factory = fetchBeanFactory(data);
 334  
         try
 335  
         {
 336  667
             return factory.createBean(fetchBeanClass(data, defaultClass,
 337  
                     factory), data, param);
 338  
         }
 339  7
         catch (Exception ex)
 340  
         {
 341  7
             throw new ConfigurationRuntimeException(ex);
 342  
         }
 343  
     }
 344  
 
 345  
     /**
 346  
      * Returns a bean instance for the specified declaration. This method is a
 347  
      * short cut for {@code createBean(data, null, null);}.
 348  
      *
 349  
      * @param data the bean declaration
 350  
      * @param defaultClass the class to be used when in the declaration no class
 351  
      * is specified
 352  
      * @return the new bean
 353  
      * @throws ConfigurationRuntimeException if an error occurs
 354  
      */
 355  
     public static Object createBean(BeanDeclaration data, Class<?> defaultClass)
 356  
             throws ConfigurationRuntimeException
 357  
     {
 358  668
         return createBean(data, defaultClass, null);
 359  
     }
 360  
 
 361  
     /**
 362  
      * Returns a bean instance for the specified declaration. This method is a
 363  
      * short cut for {@code createBean(data, null);}.
 364  
      *
 365  
      * @param data the bean declaration
 366  
      * @return the new bean
 367  
      * @throws ConfigurationRuntimeException if an error occurs
 368  
      */
 369  
     public static Object createBean(BeanDeclaration data)
 370  
             throws ConfigurationRuntimeException
 371  
     {
 372  318
         return createBean(data, null);
 373  
     }
 374  
 
 375  
     /**
 376  
      * Returns a {@code java.lang.Class} object for the specified name.
 377  
      * Because class loading can be tricky in some environments the code for
 378  
      * retrieving a class by its name was extracted into this helper method. So
 379  
      * if changes are necessary, they can be made at a single place.
 380  
      *
 381  
      * @param name the name of the class to be loaded
 382  
      * @param callingClass the calling class
 383  
      * @return the class object for the specified name
 384  
      * @throws ClassNotFoundException if the class cannot be loaded
 385  
      */
 386  
     static Class<?> loadClass(String name, Class<?> callingClass)
 387  
             throws ClassNotFoundException
 388  
     {
 389  313
         return ClassUtils.getClass(name);
 390  
     }
 391  
 
 392  
     /**
 393  
      * Determines the class of the bean to be created. If the bean declaration
 394  
      * contains a class name, this class is used. Otherwise it is checked
 395  
      * whether a default class is provided. If this is not the case, the
 396  
      * factory's default class is used. If this class is undefined, too, an
 397  
      * exception is thrown.
 398  
      *
 399  
      * @param data the bean declaration
 400  
      * @param defaultClass the default class
 401  
      * @param factory the bean factory to use
 402  
      * @return the class of the bean to be created
 403  
      * @throws ConfigurationRuntimeException if the class cannot be determined
 404  
      */
 405  
     private static Class<?> fetchBeanClass(BeanDeclaration data,
 406  
             Class<?> defaultClass, BeanFactory factory)
 407  
             throws ConfigurationRuntimeException
 408  
     {
 409  667
         String clsName = data.getBeanClassName();
 410  667
         if (clsName != null)
 411  
         {
 412  
             try
 413  
             {
 414  313
                 return loadClass(clsName, factory.getClass());
 415  
             }
 416  1
             catch (ClassNotFoundException cex)
 417  
             {
 418  1
                 throw new ConfigurationRuntimeException(cex);
 419  
             }
 420  
         }
 421  
 
 422  354
         if (defaultClass != null)
 423  
         {
 424  82
             return defaultClass;
 425  
         }
 426  
 
 427  272
         Class<?> clazz = factory.getDefaultBeanClass();
 428  272
         if (clazz == null)
 429  
         {
 430  1
             throw new ConfigurationRuntimeException(
 431  
                     "Bean class is not specified!");
 432  
         }
 433  271
         return clazz;
 434  
     }
 435  
 
 436  
     /**
 437  
      * Obtains the bean factory to use for creating the specified bean. This
 438  
      * method will check whether a factory is specified in the bean declaration.
 439  
      * If this is not the case, the default bean factory will be used.
 440  
      *
 441  
      * @param data the bean declaration
 442  
      * @return the bean factory to use
 443  
      * @throws ConfigurationRuntimeException if the factory cannot be determined
 444  
      */
 445  
     private static BeanFactory fetchBeanFactory(BeanDeclaration data)
 446  
             throws ConfigurationRuntimeException
 447  
     {
 448  668
         String factoryName = data.getBeanFactoryName();
 449  668
         if (factoryName != null)
 450  
         {
 451  278
             BeanFactory factory = BEAN_FACTORIES.get(factoryName);
 452  278
             if (factory == null)
 453  
             {
 454  1
                 throw new ConfigurationRuntimeException(
 455  
                         "Unknown bean factory: " + factoryName);
 456  
             }
 457  
             else
 458  
             {
 459  277
                 return factory;
 460  
             }
 461  
         }
 462  
         else
 463  
         {
 464  390
             return getDefaultBeanFactory();
 465  
         }
 466  
     }
 467  
 }