/*
* Copyright (C) 2010 Google Inc.
*
* 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 com.google.clearsilver.jsilver.resourceloader;
import com.google.clearsilver.jsilver.exceptions.JSilverTemplateNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
/**
* Loads resources from classpath, alongside a given class.
*
* <p>For example, suppose the classpath contains:
* <pre>
* com/foo/SomeThing.class
* com/foo/my-template.cs
* com/foo/subdir/another-template.cs
* </pre>
*
* <p>You can access the resources in the class's package like this:
* <pre>
* ResourceLoader loader = new ClassResourceLoader(SomeThing.class);
* loader.open("my-template.cs");
* loader.open("subdir/my-template.cs");
* </pre>
* Or by using a relative path:
* <pre>
* ResourceLoader loader = new ClassResourceLoader(Something.class, "subdir");
* loader.open("my-template.cs");
* </pre>
*
* @see ResourceLoader
* @see ClassLoaderResourceLoader
*/
public class ClassResourceLoader extends BufferedResourceLoader {
private final Class<?> cls;
private final String basePath;
public ClassResourceLoader(Class<?> cls) {
this.cls = cls;
this.basePath = "/" + cls.getPackage().getName().replace('.', '/');
}
/**
* Load resources from the given subdirectory {@code basePath},
* relative to the .class file of {@code cls}.
*/
public ClassResourceLoader(Class<?> cls, String basePath) {
this.cls = cls;
this.basePath = basePath;
}
@Override
public Reader open(String name) throws IOException {
InputStream stream = cls.getResourceAsStream(basePath + '/' + name);
return stream == null ? null : buffer(new InputStreamReader(stream, getCharacterSet()));
}
@Override
public Reader openOrFail(String name) throws JSilverTemplateNotFoundException, IOException {
Reader reader = open(name);
if (reader == null) {
throw new JSilverTemplateNotFoundException("No '" + name + "' as class resource of "
+ cls.getName());
} else {
return reader;
}
}
}