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Diffstat (limited to 'velocity-engine-core/src/main/java/org/apache/velocity/runtime/resource/loader/ClasspathResourceLoader.java')
| -rw-r--r-- | velocity-engine-core/src/main/java/org/apache/velocity/runtime/resource/loader/ClasspathResourceLoader.java | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/velocity-engine-core/src/main/java/org/apache/velocity/runtime/resource/loader/ClasspathResourceLoader.java b/velocity-engine-core/src/main/java/org/apache/velocity/runtime/resource/loader/ClasspathResourceLoader.java new file mode 100644 index 00000000..9bfd0f14 --- /dev/null +++ b/velocity-engine-core/src/main/java/org/apache/velocity/runtime/resource/loader/ClasspathResourceLoader.java @@ -0,0 +1,169 @@ +package org.apache.velocity.runtime.resource.loader; + +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +import org.apache.commons.lang3.StringUtils; +import org.apache.velocity.exception.ResourceNotFoundException; +import org.apache.velocity.runtime.resource.Resource; +import org.apache.velocity.util.ClassUtils; +import org.apache.velocity.util.ExtProperties; + +import java.io.IOException; +import java.io.InputStream; +import java.io.Reader; + +/** + * ClasspathResourceLoader is a simple loader that will load + * templates from the classpath. + * <br> + * <br> + * Will load templates from from multiple instances of + * and arbitrary combinations of: + * <ul> + * <li> jar files + * <li> zip files + * <li> template directories (any directory containing templates) + * </ul> + * This is a configuration-free loader, in that there are no + * parameters to be specified in the configuration properties, + * other than specifying this as the loader to use. For example + * the following is all that the loader needs to be functional: + * <br> + * <pre><code> + * resource.loaders = class + * resource.loader.class.class =org.apache.velocity.runtime.resource.loader.ClasspathResourceLoader + * </code></pre> + * <br> + * <br> + * To use, put your template directories, jars + * and zip files into the classpath or other mechanisms that make + * resources accessible to the classloader. + * <br> + * <br> + * This makes deployment trivial for web applications running in + * any Servlet 2.2 compliant servlet runner, such as Tomcat 3.2 + * and others. + * <br> + * <br> + * For a Servlet Spec v2.2 servlet runner, + * just drop the jars of template files into the WEB-INF/lib + * directory of your webapp, and you won't have to worry about setting + * template paths or altering them with the root of the webapp + * before initializing. + * <br> + * <br> + * I have also tried it with a WAR deployment, and that seemed to + * work just fine. + * + * @author <a href="mailto:mailmur@yahoo.com">Aki Nieminen</a> + * @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a> + * @version $Id$ + */ +public class ClasspathResourceLoader extends ResourceLoader +{ + + /** + * This is abstract in the base class, so we need it + * @param configuration + */ + @Override + public void init(ExtProperties configuration) + { + log.trace("ClasspathResourceLoader: initialization complete."); + } + + /** + * Get a Reader so that the Runtime can build a + * template with it. + * + * @param name name of template to get + * @param encoding asked encoding + * @return InputStream containing the template + * @throws ResourceNotFoundException if template not found + * in classpath. + * @since 2.0 + */ + @Override + public Reader getResourceReader(String name, String encoding ) + throws ResourceNotFoundException + { + Reader result = null; + + if (StringUtils.isEmpty(name)) + { + throw new ResourceNotFoundException ("No template name provided"); + } + + /* + * look for resource in thread classloader first (e.g. WEB-INF\lib in + * a servlet container) then fall back to the system classloader. + */ + + InputStream rawStream = null; + try + { + rawStream = ClassUtils.getResourceAsStream( getClass(), name ); + if (rawStream != null) + { + result = buildReader(rawStream, encoding); + } + } + catch( Exception fnfe ) + { + if (rawStream != null) + { + try + { + rawStream.close(); + } + catch (IOException ioe) {} + } + throw new ResourceNotFoundException("ClasspathResourceLoader problem with template: " + name, fnfe, rsvc.getLogContext().getStackTrace() ); + } + + if (result == null) + { + String msg = "ClasspathResourceLoader Error: cannot find resource " + name; + + throw new ResourceNotFoundException( msg, null, rsvc.getLogContext().getStackTrace() ); + } + + return result; + } + + /** + * @see ResourceLoader#isSourceModified(org.apache.velocity.runtime.resource.Resource) + */ + @Override + public boolean isSourceModified(Resource resource) + { + return false; + } + + /** + * @see ResourceLoader#getLastModified(org.apache.velocity.runtime.resource.Resource) + */ + @Override + public long getLastModified(Resource resource) + { + return 0; + } +} + |