001/*
002 * Copyright 2002-2014 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.web.context.support;
018
019import java.io.IOException;
020
021import org.springframework.beans.BeansException;
022import org.springframework.beans.factory.support.DefaultListableBeanFactory;
023import org.springframework.beans.factory.xml.ResourceEntityResolver;
024import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
025
026/**
027 * {@link org.springframework.web.context.WebApplicationContext} implementation
028 * which takes its configuration from XML documents, understood by an
029 * {@link org.springframework.beans.factory.xml.XmlBeanDefinitionReader}.
030 * This is essentially the equivalent of
031 * {@link org.springframework.context.support.GenericXmlApplicationContext}
032 * for a web environment.
033 *
034 * <p>By default, the configuration will be taken from "/WEB-INF/applicationContext.xml"
035 * for the root context, and "/WEB-INF/test-servlet.xml" for a context with the namespace
036 * "test-servlet" (like for a DispatcherServlet instance with the servlet-name "test").
037 *
038 * <p>The config location defaults can be overridden via the "contextConfigLocation"
039 * context-param of {@link org.springframework.web.context.ContextLoader} and servlet
040 * init-param of {@link org.springframework.web.servlet.FrameworkServlet}. Config locations
041 * can either denote concrete files like "/WEB-INF/context.xml" or Ant-style patterns
042 * like "/WEB-INF/*-context.xml" (see {@link org.springframework.util.PathMatcher}
043 * javadoc for pattern details).
044 *
045 * <p>Note: In case of multiple config locations, later bean definitions will
046 * override ones defined in earlier loaded files. This can be leveraged to
047 * deliberately override certain bean definitions via an extra XML file.
048 *
049 * <p><b>For a WebApplicationContext that reads in a different bean definition format,
050 * create an analogous subclass of {@link AbstractRefreshableWebApplicationContext}.</b>
051 * Such a context implementation can be specified as "contextClass" context-param
052 * for ContextLoader or "contextClass" init-param for FrameworkServlet.
053 *
054 * @author Rod Johnson
055 * @author Juergen Hoeller
056 * @see #setNamespace
057 * @see #setConfigLocations
058 * @see org.springframework.beans.factory.xml.XmlBeanDefinitionReader
059 * @see org.springframework.web.context.ContextLoader#initWebApplicationContext
060 * @see org.springframework.web.servlet.FrameworkServlet#initWebApplicationContext
061 */
062public class XmlWebApplicationContext extends AbstractRefreshableWebApplicationContext {
063
064        /** Default config location for the root context */
065        public static final String DEFAULT_CONFIG_LOCATION = "/WEB-INF/applicationContext.xml";
066
067        /** Default prefix for building a config location for a namespace */
068        public static final String DEFAULT_CONFIG_LOCATION_PREFIX = "/WEB-INF/";
069
070        /** Default suffix for building a config location for a namespace */
071        public static final String DEFAULT_CONFIG_LOCATION_SUFFIX = ".xml";
072
073
074        /**
075         * Loads the bean definitions via an XmlBeanDefinitionReader.
076         * @see org.springframework.beans.factory.xml.XmlBeanDefinitionReader
077         * @see #initBeanDefinitionReader
078         * @see #loadBeanDefinitions
079         */
080        @Override
081        protected void loadBeanDefinitions(DefaultListableBeanFactory beanFactory) throws BeansException, IOException {
082                // Create a new XmlBeanDefinitionReader for the given BeanFactory.
083                XmlBeanDefinitionReader beanDefinitionReader = new XmlBeanDefinitionReader(beanFactory);
084
085                // Configure the bean definition reader with this context's
086                // resource loading environment.
087                beanDefinitionReader.setEnvironment(getEnvironment());
088                beanDefinitionReader.setResourceLoader(this);
089                beanDefinitionReader.setEntityResolver(new ResourceEntityResolver(this));
090
091                // Allow a subclass to provide custom initialization of the reader,
092                // then proceed with actually loading the bean definitions.
093                initBeanDefinitionReader(beanDefinitionReader);
094                loadBeanDefinitions(beanDefinitionReader);
095        }
096
097        /**
098         * Initialize the bean definition reader used for loading the bean
099         * definitions of this context. Default implementation is empty.
100         * <p>Can be overridden in subclasses, e.g. for turning off XML validation
101         * or using a different XmlBeanDefinitionParser implementation.
102         * @param beanDefinitionReader the bean definition reader used by this context
103         * @see org.springframework.beans.factory.xml.XmlBeanDefinitionReader#setValidationMode
104         * @see org.springframework.beans.factory.xml.XmlBeanDefinitionReader#setDocumentReaderClass
105         */
106        protected void initBeanDefinitionReader(XmlBeanDefinitionReader beanDefinitionReader) {
107        }
108
109        /**
110         * Load the bean definitions with the given XmlBeanDefinitionReader.
111         * <p>The lifecycle of the bean factory is handled by the refreshBeanFactory method;
112         * therefore this method is just supposed to load and/or register bean definitions.
113         * <p>Delegates to a ResourcePatternResolver for resolving location patterns
114         * into Resource instances.
115         * @throws IOException if the required XML document isn't found
116         * @see #refreshBeanFactory
117         * @see #getConfigLocations
118         * @see #getResources
119         * @see #getResourcePatternResolver
120         */
121        protected void loadBeanDefinitions(XmlBeanDefinitionReader reader) throws IOException {
122                String[] configLocations = getConfigLocations();
123                if (configLocations != null) {
124                        for (String configLocation : configLocations) {
125                                reader.loadBeanDefinitions(configLocation);
126                        }
127                }
128        }
129
130        /**
131         * The default location for the root context is "/WEB-INF/applicationContext.xml",
132         * and "/WEB-INF/test-servlet.xml" for a context with the namespace "test-servlet"
133         * (like for a DispatcherServlet instance with the servlet-name "test").
134         */
135        @Override
136        protected String[] getDefaultConfigLocations() {
137                if (getNamespace() != null) {
138                        return new String[] {DEFAULT_CONFIG_LOCATION_PREFIX + getNamespace() + DEFAULT_CONFIG_LOCATION_SUFFIX};
139                }
140                else {
141                        return new String[] {DEFAULT_CONFIG_LOCATION};
142                }
143        }
144
145}