code: /*
   * 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.skywalking.oap.log.analyzer.provider;
  
  import java.io.File;
  import java.io.FileNotFoundException;
  import java.io.FileReader;
  import java.io.IOException;
  import java.io.Reader;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.List;
  import java.util.Objects;
  import java.util.stream.Collectors;
  import lombok.Data;
  import lombok.extern.slf4j.Slf4j;
  import org.apache.skywalking.oap.server.library.module.ModuleStartException;
  import org.apache.skywalking.oap.server.library.util.ResourceUtils;
  import org.yaml.snakeyaml.Yaml;
  
  import static com.google.common.base.Preconditions.checkArgument;
  import static com.google.common.io.Files.getNameWithoutExtension;
  import static org.apache.skywalking.oap.server.library.util.StringUtil.isNotBlank;
  import static org.apache.skywalking.oap.server.library.util.CollectionUtils.isEmpty;
  
  @Data
  @Slf4j
  public class LALConfigs {
      private List<LALConfig> rules;
  
      public static List<LALConfigs> load(final String path, final List<String> files) throws Exception {
          if (isEmpty(files)) {
              return Collections.emptyList();
          }
  
          checkArgument(isNotBlank(path), "path cannot be blank");
  
          try {
              final File[] rules = ResourceUtils.getPathFiles(path);
  
              return Arrays.stream(rules)
                           .filter(File::isFile)
                           .filter(it -> {
                               //noinspection UnstableApiUsage
                               return files.contains(getNameWithoutExtension(it.getName()));
                           })
                           .map(f -> {
                               try (final Reader r = new FileReader(f)) {
                                   return new Yaml().<LALConfigs>loadAs(r, LALConfigs.class);
                               } catch (IOException e) {
                                   log.debug("Failed to read file {}", f, e);
                               }
                               return null;
                           })
                           .filter(Objects::nonNull)
                           .collect(Collectors.toList());
          } catch (FileNotFoundException e) {
              throw new ModuleStartException("Failed to load LAL config rules", e);
          }
      }
  }
  