/*
* Copyright 2002-2005 the original author or authors.
*
* Licensed 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.
*/
package org.springmodules.template.engine.freemarker;
import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Reader;
import freemarker.cache.TemplateLoader;
import org.springframework.core.io.DefaultResourceLoader;
import org.springframework.core.io.Resource;
import org.springframework.core.io.ResourceLoader;
import org.springmodules.template.TemplateResolver;
/**
* A {@link TemplateLoader} implementation that uses a {@link ResourceLoader resource loader} to load the
* template resources.
*
* @author Uri Boness
*/
public class ResourceLoaderTemplateLoader implements TemplateLoader {
private ResourceLoader resourceLoader;
/**
* Constructs a new ResourceTemplateLoader where {@link DefaultResourceLoader} is used as the resource loader.
*/
public ResourceLoaderTemplateLoader() {
this(new DefaultResourceLoader());
}
/**
* Constructs a new ResourceTemplateLoader with a given resource loader to be used to load all template
* resources.
*
* @param resourceLoader The resource loader to be used to load all template resources.
*/
public ResourceLoaderTemplateLoader(ResourceLoader resourceLoader) {
this.resourceLoader = resourceLoader;
}
/**
* Returns the {@link Resource) loaded by the configured {@link TemplateResolver} based on the given resource name.
*
* @param name The name of the resource.
* @return The loaded {@link Resource} based on the given resource name.
* @throws IOException when the requested resource could not be loaded.
* @see TemplateLoader#findTemplateSource(String)
*/
public Object findTemplateSource(String name) throws IOException {
return resourceLoader.getResource(name);
}
/**
* If the given resource represents a physical file {@link java.io.File#lastModified()} is returned. Otherwise always
* returns 0.
*
* @param object The given template {@link Resource}.
* @return The last modified timestamp (in milli-seconds) of the given resource.
* @see TemplateLoader#getLastModified(Object)
*/
public long getLastModified(Object object) {
Resource resource = (Resource)object;
File file = getResourceFile(resource);
return (file != null) ? file.lastModified() : 0;
}
public Reader getReader(Object templateSource, String encoding) throws IOException {
Resource resource = (Resource)templateSource;
return new InputStreamReader(resource.getInputStream(), encoding);
}
public void closeTemplateSource(Object templateSource) throws IOException {
// do nothing
}
/**
* Returns the internal resource loader that is used to load the freemarker templates.
*
* @return The internal resource loader that is used to load the freemarker templates.
*/
public ResourceLoader getResourceLoader() {
return resourceLoader;
}
//============================================= Helper Methods =====================================================
/**
* Tries to resolve the physical file in the file system the given resource represents. If such file could not be
* resolved or the given resource does not represent a physical file <code>null</code> is returned.
*
* @param resource The given resource.
* @return The physical file represented by the given resource, <code>null</code> if no such file could be resolved.
*/
protected File getResourceFile(Resource resource) {
try {
return resource.getFile();
} catch (IOException ioe) {
return null;
}
}
}