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.commons.configuration.beanutils;
018:
019: /**
020: * <p>
021: * The default implementation of the <code>BeanFactory</code> interface.
022: * </p>
023: * <p>
024: * This class creates beans of arbitrary types using reflection. Each time the
025: * <code>createBean()</code> method is invoked, a new bean instance is
026: * created. A default bean class is not supported.
027: * </p>
028: * <p>
029: * An instance of this factory class will be set as the default bean factory for
030: * the <code>{@link BeanHelper}</code> class. This means that if not bean
031: * factory is specified in a <code>{@link BeanDeclaration}</code>, this
032: * default instance will be used.
033: * </p>
034: *
035: * @since 1.3
036: * @author Oliver Heger
037: * @version $Id: DefaultBeanFactory.java 439648 2006-09-02 20:42:10Z oheger $
038: */
039: public class DefaultBeanFactory implements BeanFactory {
040: /** Stores the default instance of this class. */
041: public static final DefaultBeanFactory INSTANCE = new DefaultBeanFactory();
042:
043: /**
044: * Creates a new bean instance. This implementation delegates to the
045: * protected methods <code>createBeanInstance()</code> and
046: * <code>initBeanInstance()</code> for creating and initializing the bean.
047: * This makes it easier for derived classes that need to change specific
048: * functionality of the base class.
049: *
050: * @param beanClass the class of the bean, from which an instance is to be
051: * created
052: * @param data the bean declaration object
053: * @param parameter an additional parameter (ignored by this implementation)
054: * @return the new bean instance
055: * @throws Exception if an error occurs
056: */
057: public Object createBean(Class beanClass, BeanDeclaration data,
058: Object parameter) throws Exception {
059: Object result = createBeanInstance(beanClass, data);
060: initBeanInstance(result, data);
061: return result;
062: }
063:
064: /**
065: * Returns the default bean class used by this factory. This is always
066: * <b>null</b> for this implementation.
067: *
068: * @return the default bean class
069: */
070: public Class getDefaultBeanClass() {
071: return null;
072: }
073:
074: /**
075: * Creates the bean instance. This method is called by
076: * <code>createBean()</code>. It uses reflection to create a new instance
077: * of the specified class.
078: *
079: * @param beanClass the class of the bean to be created
080: * @param data the bean declaration
081: * @return the new bean instance
082: * @throws Exception if an error occurs
083: */
084: protected Object createBeanInstance(Class beanClass,
085: BeanDeclaration data) throws Exception {
086: return beanClass.newInstance();
087: }
088:
089: /**
090: * Initializes the newly created bean instance. This method is called by
091: * <code>createBean()</code>. It calls the
092: * <code>{@link BeanHelper#initBean(Object, BeanDeclaration) initBean()}</code>
093: * of <code>{@link BeanHelper}</code> for performing the initialization.
094: *
095: * @param bean the newly created bean instance
096: * @param data the bean declaration object
097: * @throws Exception if an error occurs
098: */
099: protected void initBeanInstance(Object bean, BeanDeclaration data)
100: throws Exception {
101: BeanHelper.initBean(bean, data);
102: }
103: }
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