Coverage Report - org.apache.commons.configuration.beanutils.BeanHelper
 
Classes in this File Line Coverage Branch Coverage Complexity
BeanHelper
93%
56/60
100%
14/14
3,357
 
 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.lang.reflect.InvocationTargetException;
 20  
 import java.util.HashMap;
 21  
 import java.util.Iterator;
 22  
 import java.util.Map;
 23  
 import java.util.Set;
 24  
 
 25  
 import org.apache.commons.beanutils.BeanUtils;
 26  
 import org.apache.commons.beanutils.PropertyUtils;
 27  
 import org.apache.commons.configuration.ConfigurationRuntimeException;
 28  
 import org.apache.commons.lang.ClassUtils;
 29  
 
 30  
 /**
 31  
  * <p>
 32  
  * A helper class for creating bean instances that are defined in configuration
 33  
  * files.
 34  
  * </p>
 35  
  * <p>
 36  
  * This class provides static utility methods related to bean creation
 37  
  * operations. These methods simplify such operations because a client need not
 38  
  * deal with all involved interfaces. Usually, if a bean declaration has already
 39  
  * been obtained, a single method call is necessary to create a new bean
 40  
  * instance.
 41  
  * </p>
 42  
  * <p>
 43  
  * This class also supports the registration of custom bean factories.
 44  
  * Implementations of the <code>{@link BeanFactory}</code> interface can be
 45  
  * registered under a symbolic name using the <code>registerBeanFactory()</code>
 46  
  * method. In the configuration file the name of the bean factory can be
 47  
  * specified in the bean declaration. Then this factory will be used to create
 48  
  * the bean.
 49  
  * </p>
 50  
  *
 51  
  * @since 1.3
 52  
  * @author Oliver Heger
 53  
  * @version $Id: BeanHelper.java 508152 2007-02-15 21:16:37Z oheger $
 54  
  */
 55  
 public class BeanHelper
 56  
 {
 57  
     /** Stores a map with the registered bean factories. */
 58  8
     private static Map beanFactories = new HashMap();
 59  
 
 60  
     /**
 61  
      * Stores the default bean factory, which will be used if no other factory
 62  
      * is provided.
 63  
      */
 64  4
     private static BeanFactory defaultBeanFactory = DefaultBeanFactory.INSTANCE;
 65  
 
 66  
     /**
 67  
      * Private constructor, so no instances can be created.
 68  
      */
 69  
     private BeanHelper()
 70  0
     {
 71  0
     }
 72  
 
 73  
     /**
 74  
      * Register a bean factory under a symbolic name. This factory object can
 75  
      * then be specified in bean declarations with the effect that this factory
 76  
      * will be used to obtain an instance for the corresponding bean
 77  
      * declaration.
 78  
      *
 79  
      * @param name the name of the factory
 80  
      * @param factory the factory to be registered
 81  
      */
 82  
     public static void registerBeanFactory(String name, BeanFactory factory)
 83  
     {
 84  13
         if (name == null)
 85  
         {
 86  1
             throw new IllegalArgumentException(
 87  
                     "Name for bean factory must not be null!");
 88  
         }
 89  12
         if (factory == null)
 90  
         {
 91  1
             throw new IllegalArgumentException("Bean factory must not be null!");
 92  
         }
 93  
 
 94  11
         beanFactories.put(name, factory);
 95  11
     }
 96  
 
 97  
     /**
 98  
      * Deregisters the bean factory with the given name. After that this factory
 99  
      * cannot be used any longer.
 100  
      *
 101  
      * @param name the name of the factory to be deregistered
 102  
      * @return the factory that was registered under this name; <b>null</b> if
 103  
      * there was no such factory
 104  
      */
 105  
     public static BeanFactory deregisterBeanFactory(String name)
 106  
     {
 107  11
         return (BeanFactory) beanFactories.remove(name);
 108  
     }
 109  
 
 110  
     /**
 111  
      * Returns a set with the names of all currently registered bean factories.
 112  
      *
 113  
      * @return a set with the names of the registered bean factories
 114  
      */
 115  
     public static Set registeredFactoryNames()
 116  
     {
 117  42
         return beanFactories.keySet();
 118  
     }
 119  
 
 120  
     /**
 121  
      * Returns the default bean factory.
 122  
      *
 123  
      * @return the default bean factory
 124  
      */
 125  
     public static BeanFactory getDefaultBeanFactory()
 126  
     {
 127  69
         return defaultBeanFactory;
 128  
     }
 129  
 
 130  
     /**
 131  
      * Sets the default bean factory. This factory will be used for all create
 132  
      * operations, for which no special factory is provided in the bean
 133  
      * declaration.
 134  
      *
 135  
      * @param factory the default bean factory (must not be <b>null</b>)
 136  
      */
 137  
     public static void setDefaultBeanFactory(BeanFactory factory)
 138  
     {
 139  22
         if (factory == null)
 140  
         {
 141  1
             throw new IllegalArgumentException(
 142  
                     "Default bean factory must not be null!");
 143  
         }
 144  21
         defaultBeanFactory = factory;
 145  21
     }
 146  
 
 147  
     /**
 148  
      * Initializes the passed in bean. This method will obtain all the bean's
 149  
      * properties that are defined in the passed in bean declaration. These
 150  
      * properties will be set on the bean. If necessary, further beans will be
 151  
      * created recursively.
 152  
      *
 153  
      * @param bean the bean to be initialized
 154  
      * @param data the bean declaration
 155  
      * @throws ConfigurationRuntimeException if a property cannot be set
 156  
      */
 157  
     public static void initBean(Object bean, BeanDeclaration data)
 158  
             throws ConfigurationRuntimeException
 159  
     {
 160  109
         Map properties = data.getBeanProperties();
 161  109
         if (properties != null)
 162  
         {
 163  317
             for (Iterator it = properties.keySet().iterator(); it.hasNext();)
 164  
             {
 165  102
                 String propName = (String) it.next();
 166  102
                 initProperty(bean, propName, properties.get(propName));
 167  
             }
 168  
         }
 169  
 
 170  108
         Map nestedBeans = data.getNestedBeanDeclarations();
 171  108
         if (nestedBeans != null)
 172  
         {
 173  218
             for (Iterator it = nestedBeans.keySet().iterator(); it.hasNext();)
 174  
             {
 175  18
                 String propName = (String) it.next();
 176  18
                 initProperty(bean, propName, createBean(
 177  
                         (BeanDeclaration) nestedBeans.get(propName), null));
 178  
             }
 179  
         }
 180  108
     }
 181  
 
 182  
     /**
 183  
      * Sets a property on the given bean using Common Beanutils.
 184  
      *
 185  
      * @param bean the bean
 186  
      * @param propName the name of the property
 187  
      * @param value the property's value
 188  
      * @throws ConfigurationRuntimeException if the property is not writeable or
 189  
      * an error occurred
 190  
      */
 191  
     private static void initProperty(Object bean, String propName, Object value)
 192  
             throws ConfigurationRuntimeException
 193  
     {
 194  120
         if (!PropertyUtils.isWriteable(bean, propName))
 195  
         {
 196  1
             throw new ConfigurationRuntimeException("Property " + propName
 197  
                     + " cannot be set!");
 198  
         }
 199  
 
 200  
         try
 201  
         {
 202  119
             BeanUtils.setProperty(bean, propName, value);
 203  119
         }
 204  
         catch (IllegalAccessException iaex)
 205  
         {
 206  0
             throw new ConfigurationRuntimeException(iaex);
 207  
         }
 208  
         catch (InvocationTargetException itex)
 209  
         {
 210  0
             throw new ConfigurationRuntimeException(itex);
 211  
         }
 212  119
     }
 213  
 
 214  
     /**
 215  
      * The main method for creating and initializing beans from a configuration.
 216  
      * This method will return an initialized instance of the bean class
 217  
      * specified in the passed in bean declaration. If this declaration does not
 218  
      * contain the class of the bean, the passed in default class will be used.
 219  
      * From the bean declaration the factory to be used for creating the bean is
 220  
      * queried. The declaration may here return <b>null</b>, then a default
 221  
      * factory is used. This factory is then invoked to perform the create
 222  
      * operation.
 223  
      *
 224  
      * @param data the bean declaration
 225  
      * @param defaultClass the default class to use
 226  
      * @param param an additional parameter that will be passed to the bean
 227  
      * factory; some factories may support parameters and behave different
 228  
      * depending on the value passed in here
 229  
      * @return the new bean
 230  
      * @throws ConfigurationRuntimeException if an error occurs
 231  
      */
 232  
     public static Object createBean(BeanDeclaration data, Class defaultClass,
 233  
             Object param) throws ConfigurationRuntimeException
 234  
     {
 235  110
         if (data == null)
 236  
         {
 237  1
             throw new IllegalArgumentException(
 238  
                     "Bean declaration must not be null!");
 239  
         }
 240  
 
 241  109
         BeanFactory factory = fetchBeanFactory(data);
 242  
         try
 243  
         {
 244  108
             return factory.createBean(fetchBeanClass(data, defaultClass,
 245  
                     factory), data, param);
 246  
         }
 247  
         catch (Exception ex)
 248  
         {
 249  5
             throw new ConfigurationRuntimeException(ex);
 250  
         }
 251  
     }
 252  
 
 253  
     /**
 254  
      * Returns a bean instance for the specified declaration. This method is a
 255  
      * short cut for <code>createBean(data, null, null);</code>.
 256  
      *
 257  
      * @param data the bean declaration
 258  
      * @param defaultClass the class to be used when in the declation no class
 259  
      * is specified
 260  
      * @return the new bean
 261  
      * @throws ConfigurationRuntimeException if an error occurs
 262  
      */
 263  
     public static Object createBean(BeanDeclaration data, Class defaultClass)
 264  
             throws ConfigurationRuntimeException
 265  
     {
 266  109
         return createBean(data, defaultClass, null);
 267  
     }
 268  
 
 269  
     /**
 270  
      * Returns a bean instance for the specified declaration. This method is a
 271  
      * short cut for <code>createBean(data, null);</code>.
 272  
      *
 273  
      * @param data the bean declaration
 274  
      * @return the new bean
 275  
      * @throws ConfigurationRuntimeException if an error occurs
 276  
      */
 277  
     public static Object createBean(BeanDeclaration data)
 278  
             throws ConfigurationRuntimeException
 279  
     {
 280  63
         return createBean(data, null);
 281  
     }
 282  
 
 283  
     /**
 284  
      * Returns a <code>java.lang.Class</code> object for the specified name.
 285  
      * This method and the helper method it invokes are very similar to code
 286  
      * extracted from the <code>ClassLoaderUtils</code> class of Commons
 287  
      * Jelly. It should be replaced if Commons Lang provides a generic version.
 288  
      *
 289  
      * @param name the name of the class to be loaded
 290  
      * @param callingClass the calling class
 291  
      * @return the class object for the specified name
 292  
      * @throws ClassNotFoundException if the class cannot be loaded
 293  
      */
 294  
     static Class loadClass(String name, Class callingClass)
 295  
             throws ClassNotFoundException
 296  
     {
 297  23
         return ClassUtils.getClass(name);
 298  
     }
 299  
 
 300  
     /**
 301  
      * Determines the class of the bean to be created. If the bean declaration
 302  
      * contains a class name, this class is used. Otherwise it is checked
 303  
      * whether a default class is provided. If this is not the case, the
 304  
      * factory's default class is used. If this class is undefined, too, an
 305  
      * exception is thrown.
 306  
      *
 307  
      * @param data the bean declaration
 308  
      * @param defaultClass the default class
 309  
      * @param factory the bean factory to use
 310  
      * @return the class of the bean to be created
 311  
      * @throws ConfigurationRuntimeException if the class cannot be determined
 312  
      */
 313  
     private static Class fetchBeanClass(BeanDeclaration data,
 314  
             Class defaultClass, BeanFactory factory)
 315  
             throws ConfigurationRuntimeException
 316  
     {
 317  108
         String clsName = data.getBeanClassName();
 318  108
         if (clsName != null)
 319  
         {
 320  
             try
 321  
             {
 322  23
                 return loadClass(clsName, factory.getClass());
 323  
             }
 324  
             catch (ClassNotFoundException cex)
 325  
             {
 326  1
                 throw new ConfigurationRuntimeException(cex);
 327  
             }
 328  
         }
 329  
 
 330  85
         if (defaultClass != null)
 331  
         {
 332  21
             return defaultClass;
 333  
         }
 334  
 
 335  64
         Class clazz = factory.getDefaultBeanClass();
 336  64
         if (clazz == null)
 337  
         {
 338  1
             throw new ConfigurationRuntimeException(
 339  
                     "Bean class is not specified!");
 340  
         }
 341  63
         return clazz;
 342  
     }
 343  
 
 344  
     /**
 345  
      * Obtains the bean factory to use for creating the specified bean. This
 346  
      * method will check whether a factory is specified in the bean declaration.
 347  
      * If this is not the case, the default bean factory will be used.
 348  
      *
 349  
      * @param data the bean declaration
 350  
      * @return the bean factory to use
 351  
      * @throws ConfigurationRuntimeException if the factory cannot be determined
 352  
      */
 353  
     private static BeanFactory fetchBeanFactory(BeanDeclaration data)
 354  
             throws ConfigurationRuntimeException
 355  
     {
 356  109
         String factoryName = data.getBeanFactoryName();
 357  109
         if (factoryName != null)
 358  
         {
 359  70
             BeanFactory factory = (BeanFactory) beanFactories.get(factoryName);
 360  70
             if (factory == null)
 361  
             {
 362  1
                 throw new ConfigurationRuntimeException(
 363  
                         "Unknown bean factory: " + factoryName);
 364  
             }
 365  
             else
 366  
             {
 367  69
                 return factory;
 368  
             }
 369  
         }
 370  
         else
 371  
         {
 372  39
             return getDefaultBeanFactory();
 373  
         }
 374  
     }
 375  
 }