1 /* 2 * Copyright 2002-2008 the original author or authors. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package org.springframework.web.servlet.view.velocity; 18 19 import java.io.IOException; 20 21 import javax.servlet.ServletContext; 22 23 import org.apache.velocity.app.VelocityEngine; 24 import org.apache.velocity.exception.VelocityException; 25 import org.apache.velocity.runtime.resource.loader.ClasspathResourceLoader; 26 27 import org.springframework.beans.factory.InitializingBean; 28 import org.springframework.context.ResourceLoaderAware; 29 import org.springframework.ui.velocity.VelocityEngineFactory; 30 import org.springframework.web.context.ServletContextAware; 31 32 /** 33 * JavaBean to configure Velocity for web usage, via the "configLocation" 34 * and/or "velocityProperties" and/or "resourceLoaderPath" bean properties. 35 * The simplest way to use this class is to specify just a "resourceLoaderPath"; 36 * you do not need any further configuration then. 37 * 38 * <pre class="code"> 39 * <bean id="velocityConfig" class="org.springframework.web.servlet.view.velocity.VelocityConfigurer"> 40 * <property name="resourceLoaderPath"><value>/WEB-INF/velocity/</value></property> 41 * </bean></pre> 42 * 43 * This bean must be included in the application context of any application 44 * using Spring's {@link VelocityView} for web MVC. It exists purely to configure 45 * Velocity; it is not meant to be referenced by application components (just 46 * internally by VelocityView). This class implements {@link VelocityConfig} 47 * in order to be found by VelocityView without depending on the bean name of 48 * this configurer. Each DispatcherServlet may define its own VelocityConfigurer 49 * if desired, potentially with different template loader paths. 50 * 51 * <p>Note that you can also refer to a pre-configured VelocityEngine 52 * instance via the "velocityEngine" property, e.g. set up by 53 * {@link org.springframework.ui.velocity.VelocityEngineFactoryBean}, 54 * This allows to share a VelocityEngine for web and email usage, for example. 55 * 56 * <p>This configurer registers the "spring.vm" Velocimacro library for web views 57 * (contained in this package and thus in <code>spring.jar</code>), which makes 58 * all of Spring's default Velocity macros available to the views. 59 * This allows for using the Spring-provided macros such as follows: 60 * 61 * <pre class="code"> 62 * #springBind("person.age") 63 * age is ${status.value}</pre> 64 * 65 * @author Rod Johnson 66 * @author Juergen Hoeller 67 * @author Darren Davison 68 * @see #setConfigLocation 69 * @see #setVelocityProperties 70 * @see #setResourceLoaderPath 71 * @see #setVelocityEngine 72 * @see VelocityView 73 */ 74 public class VelocityConfigurer extends VelocityEngineFactory 75 implements VelocityConfig, InitializingBean, ResourceLoaderAware, ServletContextAware { 76 77 /** the name of the resource loader for Spring's bind macros */ 78 private static final String SPRING_MACRO_RESOURCE_LOADER_NAME = "springMacro"; 79 80 /** the key for the class of Spring's bind macro resource loader */ 81 private static final String SPRING_MACRO_RESOURCE_LOADER_CLASS = "springMacro.resource.loader.class"; 82 83 /** the name of Spring's default bind macro library */ 84 private static final String SPRING_MACRO_LIBRARY = "org/springframework/web/servlet/view/velocity/spring.vm"; 85 86 87 private VelocityEngine velocityEngine; 88 89 private ServletContext servletContext; 90 91 92 /** 93 * Set a pre-configured VelocityEngine to use for the Velocity web 94 * configuration: e.g. a shared one for web and email usage, set up via 95 * {@link org.springframework.ui.velocity.VelocityEngineFactoryBean}. 96 * <p>Note that the Spring macros will <i>not</i> be enabled automatically in 97 * case of an external VelocityEngine passed in here. Make sure to include 98 * <code>spring.vm</code> in your template loader path in such a scenario 99 * (if there is an actual need to use those macros). 100 * <p>If this is not set, VelocityEngineFactory's properties 101 * (inherited by this class) have to be specified. 102 */ setVelocityEngine(VelocityEngine velocityEngine)103 public void setVelocityEngine(VelocityEngine velocityEngine) { 104 this.velocityEngine = velocityEngine; 105 } 106 setServletContext(ServletContext servletContext)107 public void setServletContext(ServletContext servletContext) { 108 this.servletContext = servletContext; 109 } 110 111 /** 112 * Initialize VelocityEngineFactory's VelocityEngine 113 * if not overridden by a pre-configured VelocityEngine. 114 * @see #createVelocityEngine 115 * @see #setVelocityEngine 116 */ afterPropertiesSet()117 public void afterPropertiesSet() throws IOException, VelocityException { 118 if (this.velocityEngine == null) { 119 this.velocityEngine = createVelocityEngine(); 120 } 121 } 122 123 /** 124 * Provides a ClasspathResourceLoader in addition to any default or user-defined 125 * loader in order to load the spring Velocity macros from the class path. 126 * @see org.apache.velocity.runtime.resource.loader.ClasspathResourceLoader 127 */ 128 @Override postProcessVelocityEngine(VelocityEngine velocityEngine)129 protected void postProcessVelocityEngine(VelocityEngine velocityEngine) { 130 velocityEngine.setApplicationAttribute(ServletContext.class.getName(), this.servletContext); 131 velocityEngine.setProperty( 132 SPRING_MACRO_RESOURCE_LOADER_CLASS, ClasspathResourceLoader.class.getName()); 133 velocityEngine.addProperty( 134 VelocityEngine.RESOURCE_LOADER, SPRING_MACRO_RESOURCE_LOADER_NAME); 135 velocityEngine.addProperty( 136 VelocityEngine.VM_LIBRARY, SPRING_MACRO_LIBRARY); 137 138 if (logger.isInfoEnabled()) { 139 logger.info("ClasspathResourceLoader with name '" + SPRING_MACRO_RESOURCE_LOADER_NAME + 140 "' added to configured VelocityEngine"); 141 } 142 } 143 getVelocityEngine()144 public VelocityEngine getVelocityEngine() { 145 return this.velocityEngine; 146 } 147 148 } 149