001/* 002 * Copyright 2002-2012 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.ui.velocity; 018 019import java.io.IOException; 020import java.io.InputStream; 021import java.util.Arrays; 022 023import org.apache.commons.collections.ExtendedProperties; 024import org.apache.commons.logging.Log; 025import org.apache.commons.logging.LogFactory; 026import org.apache.velocity.exception.ResourceNotFoundException; 027import org.apache.velocity.runtime.resource.Resource; 028import org.apache.velocity.runtime.resource.loader.ResourceLoader; 029 030import org.springframework.util.StringUtils; 031 032/** 033 * Velocity ResourceLoader adapter that loads via a Spring ResourceLoader. 034 * Used by VelocityEngineFactory for any resource loader path that cannot 035 * be resolved to a {@code java.io.File}. 036 * 037 * <p>Note that this loader does not allow for modification detection: 038 * Use Velocity's default FileResourceLoader for {@code java.io.File} 039 * resources. 040 * 041 * <p>Expects "spring.resource.loader" and "spring.resource.loader.path" 042 * application attributes in the Velocity runtime: the former of type 043 * {@code org.springframework.core.io.ResourceLoader}, the latter a String. 044 * 045 * @author Juergen Hoeller 046 * @since 14.03.2004 047 * @see VelocityEngineFactory#setResourceLoaderPath 048 * @see org.springframework.core.io.ResourceLoader 049 * @see org.apache.velocity.runtime.resource.loader.FileResourceLoader 050 */ 051public class SpringResourceLoader extends ResourceLoader { 052 053 public static final String NAME = "spring"; 054 055 public static final String SPRING_RESOURCE_LOADER_CLASS = "spring.resource.loader.class"; 056 057 public static final String SPRING_RESOURCE_LOADER_CACHE = "spring.resource.loader.cache"; 058 059 public static final String SPRING_RESOURCE_LOADER = "spring.resource.loader"; 060 061 public static final String SPRING_RESOURCE_LOADER_PATH = "spring.resource.loader.path"; 062 063 064 protected final Log logger = LogFactory.getLog(getClass()); 065 066 private org.springframework.core.io.ResourceLoader resourceLoader; 067 068 private String[] resourceLoaderPaths; 069 070 071 @Override 072 public void init(ExtendedProperties configuration) { 073 this.resourceLoader = (org.springframework.core.io.ResourceLoader) 074 this.rsvc.getApplicationAttribute(SPRING_RESOURCE_LOADER); 075 String resourceLoaderPath = (String) this.rsvc.getApplicationAttribute(SPRING_RESOURCE_LOADER_PATH); 076 if (this.resourceLoader == null) { 077 throw new IllegalArgumentException( 078 "'resourceLoader' application attribute must be present for SpringResourceLoader"); 079 } 080 if (resourceLoaderPath == null) { 081 throw new IllegalArgumentException( 082 "'resourceLoaderPath' application attribute must be present for SpringResourceLoader"); 083 } 084 this.resourceLoaderPaths = StringUtils.commaDelimitedListToStringArray(resourceLoaderPath); 085 for (int i = 0; i < this.resourceLoaderPaths.length; i++) { 086 String path = this.resourceLoaderPaths[i]; 087 if (!path.endsWith("/")) { 088 this.resourceLoaderPaths[i] = path + "/"; 089 } 090 } 091 if (logger.isInfoEnabled()) { 092 logger.info("SpringResourceLoader for Velocity: using resource loader [" + this.resourceLoader + 093 "] and resource loader paths " + Arrays.asList(this.resourceLoaderPaths)); 094 } 095 } 096 097 @Override 098 public InputStream getResourceStream(String source) throws ResourceNotFoundException { 099 if (logger.isDebugEnabled()) { 100 logger.debug("Looking for Velocity resource with name [" + source + "]"); 101 } 102 for (String resourceLoaderPath : this.resourceLoaderPaths) { 103 org.springframework.core.io.Resource resource = 104 this.resourceLoader.getResource(resourceLoaderPath + source); 105 try { 106 return resource.getInputStream(); 107 } 108 catch (IOException ex) { 109 if (logger.isDebugEnabled()) { 110 logger.debug("Could not find Velocity resource: " + resource); 111 } 112 } 113 } 114 throw new ResourceNotFoundException( 115 "Could not find resource [" + source + "] in Spring resource loader path"); 116 } 117 118 @Override 119 public boolean isSourceModified(Resource resource) { 120 return false; 121 } 122 123 @Override 124 public long getLastModified(Resource resource) { 125 return 0; 126 } 127 128}