Coverage Report - org.apache.commons.configuration.beanutils.BeanHelper
 
Classes in this File Line Coverage Branch Coverage Complexity
BeanHelper
91%
60/66
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.Collections;
 21  
 import java.util.HashMap;
 22  
 import java.util.Iterator;
 23  
 import java.util.Map;
 24  
 import java.util.Set;
 25  
 
 26  
 import org.apache.commons.beanutils.BeanUtils;
 27  
 import org.apache.commons.beanutils.PropertyUtils;
 28  
 import org.apache.commons.configuration.ConfigurationRuntimeException;
 29  
 import org.apache.commons.lang.ClassUtils;
 30  
 
 31  
 /**
 32  
  * <p>
 33  
  * A helper class for creating bean instances that are defined in configuration
 34  
  * files.
 35  
  * </p>
 36  
  * <p>
 37  
  * This class provides static utility methods related to bean creation
 38  
  * operations. These methods simplify such operations because a client need not
 39  
  * deal with all involved interfaces. Usually, if a bean declaration has already
 40  
  * been obtained, a single method call is necessary to create a new bean
 41  
  * instance.
 42  
  * </p>
 43  
  * <p>
 44  
  * This class also supports the registration of custom bean factories.
 45  
  * Implementations of the <code>{@link BeanFactory}</code> interface can be
 46  
  * registered under a symbolic name using the <code>registerBeanFactory()</code>
 47  
  * method. In the configuration file the name of the bean factory can be
 48  
  * specified in the bean declaration. Then this factory will be used to create
 49  
  * the bean.
 50  
  * </p>
 51  
  *
 52  
  * @since 1.3
 53  
  * @author Oliver Heger
 54  
  * @version $Id: BeanHelper.java 570462 2007-08-28 15:56:49Z oheger $
 55  
  */
 56  
 public class BeanHelper
 57  
 {
 58  
     /** Stores a map with the registered bean factories. */
 59  4
     private static Map beanFactories = Collections.synchronizedMap(new HashMap());
 60  
 
 61  
     /**
 62  
      * Stores the default bean factory, which will be used if no other factory
 63  
      * is provided.
 64  
      */
 65  4
     private static BeanFactory defaultBeanFactory = DefaultBeanFactory.INSTANCE;
 66  
 
 67  
     /**
 68  
      * Private constructor, so no instances can be created.
 69  
      */
 70  
     private BeanHelper()
 71  0
     {
 72  0
     }
 73  
 
 74  
     /**
 75  
      * Register a bean factory under a symbolic name. This factory object can
 76  
      * then be specified in bean declarations with the effect that this factory
 77  
      * will be used to obtain an instance for the corresponding bean
 78  
      * declaration.
 79  
      *
 80  
      * @param name the name of the factory
 81  
      * @param factory the factory to be registered
 82  
      */
 83  
     public static void registerBeanFactory(String name, BeanFactory factory)
 84  
     {
 85  13
         if (name == null)
 86  
         {
 87  1
             throw new IllegalArgumentException(
 88  
                     "Name for bean factory must not be null!");
 89  
         }
 90  12
         if (factory == null)
 91  
         {
 92  1
             throw new IllegalArgumentException("Bean factory must not be null!");
 93  
         }
 94  
 
 95  11
         beanFactories.put(name, factory);
 96  11
     }
 97  
 
 98  
     /**
 99  
      * Deregisters the bean factory with the given name. After that this factory
 100  
      * cannot be used any longer.
 101  
      *
 102  
      * @param name the name of the factory to be deregistered
 103  
      * @return the factory that was registered under this name; <b>null</b> if
 104  
      * there was no such factory
 105  
      */
 106  
     public static BeanFactory deregisterBeanFactory(String name)
 107  
     {
 108  11
         return (BeanFactory) beanFactories.remove(name);
 109  
     }
 110  
 
 111  
     /**
 112  
      * Returns a set with the names of all currently registered bean factories.
 113  
      *
 114  
      * @return a set with the names of the registered bean factories
 115  
      */
 116  
     public static Set registeredFactoryNames()
 117  
     {
 118  122
         return beanFactories.keySet();
 119  
     }
 120  
 
 121  
     /**
 122  
      * Returns the default bean factory.
 123  
      *
 124  
      * @return the default bean factory
 125  
      */
 126  
     public static BeanFactory getDefaultBeanFactory()
 127  
     {
 128  71
         return defaultBeanFactory;
 129  
     }
 130  
 
 131  
     /**
 132  
      * Sets the default bean factory. This factory will be used for all create
 133  
      * operations, for which no special factory is provided in the bean
 134  
      * declaration.
 135  
      *
 136  
      * @param factory the default bean factory (must not be <b>null</b>)
 137  
      */
 138  
     public static void setDefaultBeanFactory(BeanFactory factory)
 139  
     {
 140  22
         if (factory == null)
 141  
         {
 142  1
             throw new IllegalArgumentException(
 143  
                     "Default bean factory must not be null!");
 144  
         }
 145  21
         defaultBeanFactory = factory;
 146  21
     }
 147  
 
 148  
     /**
 149  
      * Initializes the passed in bean. This method will obtain all the bean's
 150  
      * properties that are defined in the passed in bean declaration. These
 151  
      * properties will be set on the bean. If necessary, further beans will be
 152  
      * created recursively.
 153  
      *
 154  
      * @param bean the bean to be initialized
 155  
      * @param data the bean declaration
 156  
      * @throws ConfigurationRuntimeException if a property cannot be set
 157  
      */
 158  
     public static void initBean(Object bean, BeanDeclaration data)
 159  
             throws ConfigurationRuntimeException
 160  
     {
 161  114
         Map properties = data.getBeanProperties();
 162  114
         if (properties != null)
 163  
         {
 164  113
             for (Iterator it = properties.keySet().iterator(); it.hasNext();)
 165  
             {
 166  107
                 String propName = (String) it.next();
 167  107
                 initProperty(bean, propName, properties.get(propName));
 168  106
             }
 169  
         }
 170  
 
 171  113
         Map nestedBeans = data.getNestedBeanDeclarations();
 172  113
         if (nestedBeans != null)
 173  
         {
 174  105
             for (Iterator it = nestedBeans.keySet().iterator(); it.hasNext();)
 175  
             {
 176  18
                 String propName = (String) it.next();
 177  18
                 initProperty(bean, propName, createBean(
 178  
                         (BeanDeclaration) nestedBeans.get(propName), null));
 179  18
             }
 180  
         }
 181  113
     }
 182  
 
 183  
     /**
 184  
      * Sets a property on the given bean using Common Beanutils.
 185  
      *
 186  
      * @param bean the bean
 187  
      * @param propName the name of the property
 188  
      * @param value the property's value
 189  
      * @throws ConfigurationRuntimeException if the property is not writeable or
 190  
      * an error occurred
 191  
      */
 192  
     private static void initProperty(Object bean, String propName, Object value)
 193  
             throws ConfigurationRuntimeException
 194  
     {
 195  125
         if (!PropertyUtils.isWriteable(bean, propName))
 196  
         {
 197  1
             throw new ConfigurationRuntimeException("Property " + propName
 198  
                     + " cannot be set!");
 199  
         }
 200  
 
 201  
         try
 202  
         {
 203  124
             BeanUtils.setProperty(bean, propName, value);
 204  
         }
 205  0
         catch (IllegalAccessException iaex)
 206  
         {
 207  0
             throw new ConfigurationRuntimeException(iaex);
 208  
         }
 209  0
         catch (InvocationTargetException itex)
 210  
         {
 211  0
             throw new ConfigurationRuntimeException(itex);
 212  124
         }
 213  124
     }
 214  
 
 215  
     /**
 216  
      * The main method for creating and initializing beans from a configuration.
 217  
      * This method will return an initialized instance of the bean class
 218  
      * specified in the passed in bean declaration. If this declaration does not
 219  
      * contain the class of the bean, the passed in default class will be used.
 220  
      * From the bean declaration the factory to be used for creating the bean is
 221  
      * queried. The declaration may here return <b>null</b>, then a default
 222  
      * factory is used. This factory is then invoked to perform the create
 223  
      * operation.
 224  
      *
 225  
      * @param data the bean declaration
 226  
      * @param defaultClass the default class to use
 227  
      * @param param an additional parameter that will be passed to the bean
 228  
      * factory; some factories may support parameters and behave different
 229  
      * depending on the value passed in here
 230  
      * @return the new bean
 231  
      * @throws ConfigurationRuntimeException if an error occurs
 232  
      */
 233  
     public static Object createBean(BeanDeclaration data, Class defaultClass,
 234  
             Object param) throws ConfigurationRuntimeException
 235  
     {
 236  115
         if (data == null)
 237  
         {
 238  1
             throw new IllegalArgumentException(
 239  
                     "Bean declaration must not be null!");
 240  
         }
 241  
 
 242  114
         BeanFactory factory = fetchBeanFactory(data);
 243  
         try
 244  
         {
 245  113
             return factory.createBean(fetchBeanClass(data, defaultClass,
 246  
                     factory), data, param);
 247  
         }
 248  5
         catch (Exception ex)
 249  
         {
 250  5
             throw new ConfigurationRuntimeException(ex);
 251  
         }
 252  
     }
 253  
 
 254  
     /**
 255  
      * Returns a bean instance for the specified declaration. This method is a
 256  
      * short cut for <code>createBean(data, null, null);</code>.
 257  
      *
 258  
      * @param data the bean declaration
 259  
      * @param defaultClass the class to be used when in the declation no class
 260  
      * is specified
 261  
      * @return the new bean
 262  
      * @throws ConfigurationRuntimeException if an error occurs
 263  
      */
 264  
     public static Object createBean(BeanDeclaration data, Class defaultClass)
 265  
             throws ConfigurationRuntimeException
 266  
     {
 267  114
         return createBean(data, defaultClass, null);
 268  
     }
 269  
 
 270  
     /**
 271  
      * Returns a bean instance for the specified declaration. This method is a
 272  
      * short cut for <code>createBean(data, null);</code>.
 273  
      *
 274  
      * @param data the bean declaration
 275  
      * @return the new bean
 276  
      * @throws ConfigurationRuntimeException if an error occurs
 277  
      */
 278  
     public static Object createBean(BeanDeclaration data)
 279  
             throws ConfigurationRuntimeException
 280  
     {
 281  66
         return createBean(data, null);
 282  
     }
 283  
 
 284  
     /**
 285  
      * Returns a <code>java.lang.Class</code> object for the specified name.
 286  
      * This method and the helper method it invokes are very similar to code
 287  
      * extracted from the <code>ClassLoaderUtils</code> class of Commons
 288  
      * Jelly. It should be replaced if Commons Lang provides a generic version.
 289  
      *
 290  
      * @param name the name of the class to be loaded
 291  
      * @param callingClass the calling class
 292  
      * @return the class object for the specified name
 293  
      * @throws ClassNotFoundException if the class cannot be loaded
 294  
      */
 295  
     static Class loadClass(String name, Class callingClass)
 296  
             throws ClassNotFoundException
 297  
     {
 298  23
         return ClassUtils.getClass(name);
 299  
     }
 300  
 
 301  
     /**
 302  
      * Determines the class of the bean to be created. If the bean declaration
 303  
      * contains a class name, this class is used. Otherwise it is checked
 304  
      * whether a default class is provided. If this is not the case, the
 305  
      * factory's default class is used. If this class is undefined, too, an
 306  
      * exception is thrown.
 307  
      *
 308  
      * @param data the bean declaration
 309  
      * @param defaultClass the default class
 310  
      * @param factory the bean factory to use
 311  
      * @return the class of the bean to be created
 312  
      * @throws ConfigurationRuntimeException if the class cannot be determined
 313  
      */
 314  
     private static Class fetchBeanClass(BeanDeclaration data,
 315  
             Class defaultClass, BeanFactory factory)
 316  
             throws ConfigurationRuntimeException
 317  
     {
 318  113
         String clsName = data.getBeanClassName();
 319  113
         if (clsName != null)
 320  
         {
 321  
             try
 322  
             {
 323  23
                 return loadClass(clsName, factory.getClass());
 324  
             }
 325  1
             catch (ClassNotFoundException cex)
 326  
             {
 327  1
                 throw new ConfigurationRuntimeException(cex);
 328  
             }
 329  
         }
 330  
 
 331  90
         if (defaultClass != null)
 332  
         {
 333  23
             return defaultClass;
 334  
         }
 335  
 
 336  67
         Class clazz = factory.getDefaultBeanClass();
 337  67
         if (clazz == null)
 338  
         {
 339  1
             throw new ConfigurationRuntimeException(
 340  
                     "Bean class is not specified!");
 341  
         }
 342  66
         return clazz;
 343  
     }
 344  
 
 345  
     /**
 346  
      * Obtains the bean factory to use for creating the specified bean. This
 347  
      * method will check whether a factory is specified in the bean declaration.
 348  
      * If this is not the case, the default bean factory will be used.
 349  
      *
 350  
      * @param data the bean declaration
 351  
      * @return the bean factory to use
 352  
      * @throws ConfigurationRuntimeException if the factory cannot be determined
 353  
      */
 354  
     private static BeanFactory fetchBeanFactory(BeanDeclaration data)
 355  
             throws ConfigurationRuntimeException
 356  
     {
 357  114
         String factoryName = data.getBeanFactoryName();
 358  114
         if (factoryName != null)
 359  
         {
 360  73
             BeanFactory factory = (BeanFactory) beanFactories.get(factoryName);
 361  73
             if (factory == null)
 362  
             {
 363  1
                 throw new ConfigurationRuntimeException(
 364  
                         "Unknown bean factory: " + factoryName);
 365  
             }
 366  
             else
 367  
             {
 368  72
                 return factory;
 369  
             }
 370  
         }
 371  
         else
 372  
         {
 373  41
             return getDefaultBeanFactory();
 374  
         }
 375  
     }
 376  
 }