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/*
* 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.
*/
package org.apache.lucene.util;
import java.io.IOException;
import java.io.InputStream;
/**
* Simple {@link ResourceLoader} that uses {@link Module#getResourceAsStream(String)} and {@link
* Class#forName(Module,String)} to open resources and classes, respectively. Resource paths must be
* absolute to module's root.
*
* To use this class, you must open the module to the {@code org.apache.lucene.core} module,
* otherwise resources can't be looked up.
*/
public final class ModuleResourceLoader implements ResourceLoader {
private final Module module;
/** Creates an instance using the given Java Module to load resources and classes. */
public ModuleResourceLoader(Module module) {
this.module = module;
}
@Override
public InputStream openResource(String resource) throws IOException {
final var stream = module.getResourceAsStream(resource);
if (stream == null) throw new IOException("Resource not found: " + resource);
return stream;
}
@Override
public Class extends T> findClass(String cname, Class expectedType) {
try {
final var clazz = Class.forName(module, cname);
if (clazz == null) throw new ClassNotFoundException(cname);
return clazz.asSubclass(expectedType);
} catch (Exception e) {
throw new RuntimeException("Cannot load class: " + cname, e);
}
}
}