/*
 * 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;

/** Abstraction for loading resources (streams, files, and classes). */
public interface ResourceLoader {

  /** Opens a named resource */
  public InputStream openResource(String resource) throws IOException;

  /** Finds class of the name and expected type */
  public <T> Class<? extends T> findClass(String cname, Class<T> expectedType);

  /** Creates an instance of the name and expected type */
  // TODO: fix exception handling
  public default <T> T newInstance(String cname, Class<T> expectedType) {
    Class<? extends T> clazz = findClass(cname, expectedType);
    try {
      return clazz.getConstructor().newInstance();
    } catch (Exception e) {
      throw new RuntimeException("Cannot create instance: " + cname, e);
    }
  }
}
