content: /*
   * 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.asterix.external.provider;
  
  import static org.apache.asterix.external.util.ExternalDataUtils.isDeltaTable;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.lang.reflect.InvocationTargetException;
  import java.net.URL;
  import java.nio.charset.Charset;
  import java.nio.charset.StandardCharsets;
  import java.util.Collections;
  import java.util.Enumeration;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  
  import org.apache.asterix.common.exceptions.AsterixException;
  import org.apache.asterix.common.exceptions.ErrorCode;
  import org.apache.asterix.common.exceptions.RuntimeDataException;
  import org.apache.asterix.external.api.IExternalDataSourceFactory;
  import org.apache.asterix.external.api.IExternalDataSourceFactory.DataSourceType;
  import org.apache.asterix.external.api.IInputStreamFactory;
  import org.apache.asterix.external.api.IRecordReaderFactory;
  import org.apache.asterix.external.input.stream.factory.LocalFSInputStreamFactory;
  import org.apache.asterix.external.input.stream.factory.SocketServerInputStreamFactory;
  import org.apache.asterix.external.util.ExternalDataConstants;
  import org.apache.asterix.external.util.ExternalDataUtils;
  import org.apache.commons.io.IOUtils;
  import org.apache.hyracks.algebricks.common.exceptions.NotImplementedException;
  import org.apache.hyracks.api.exceptions.HyracksDataException;
  
  public class DatasourceFactoryProvider {
  
      private static final String RESOURCE = "META-INF/services/org.apache.asterix.external.api.IRecordReaderFactory";
      private static final String DEFAULT_FORMAT = "DEFAULT_FORMAT";
      private static Map<String, Map<String, Class<?>>> factories = null;
  
      private DatasourceFactoryProvider() {
      }
  
      public static IExternalDataSourceFactory getExternalDataSourceFactory(Map<String, String> configuration)
              throws HyracksDataException, AsterixException {
          // Take a copy of the configuration
          if (ExternalDataUtils.getDataSourceType(configuration).equals(DataSourceType.RECORDS)) {
              String reader = configuration.get(ExternalDataConstants.KEY_READER);
              return DatasourceFactoryProvider.getRecordReaderFactory(reader, configuration);
          } else {
              // get stream source
              String streamSource = configuration.get(ExternalDataConstants.KEY_STREAM_SOURCE);
              return DatasourceFactoryProvider.getInputStreamFactory(streamSource, configuration);
          }
      }
  
      public static IInputStreamFactory getInputStreamFactory(String streamSource, Map<String, String> configuration)
              throws HyracksDataException {
          IInputStreamFactory streamSourceFactory;
          if (ExternalDataUtils.isExternal(streamSource)) {
              //DataverseName dataverse = ExternalDataUtils.getDataverse(configuration);
              //streamSourceFactory =
              //        ExternalDataUtils.createExternalInputStreamFactory(libraryManager, dataverse, streamSource);
              throw new NotImplementedException();
          } else {
              switch (streamSource) {
                  case ExternalDataConstants.KEY_ADAPTER_NAME_LOCALFS:
                      streamSourceFactory = new LocalFSInputStreamFactory();
                      break;
                  case ExternalDataConstants.KEY_ADAPTER_NAME_SOCKET:
                  case ExternalDataConstants.KEY_ALIAS_ADAPTER_NAME_SOCKET:
                      streamSourceFactory = new SocketServerInputStreamFactory();
                      break;
                  case ExternalDataConstants.STREAM_SOCKET_CLIENT:
                      streamSourceFactory = new SocketServerInputStreamFactory();
                      break;
                  default:
                      try {
                          streamSourceFactory = (IInputStreamFactory) Class.forName(streamSource).newInstance();
                      } catch (Exception e) {
                          throw new RuntimeDataException(
                                  ErrorCode.PROVIDER_DATASOURCE_FACTORY_UNKNOWN_INPUT_STREAM_FACTORY, e, streamSource);
                      }
              }
          }
          return streamSourceFactory;
      }
  
      protected static IRecordReaderFactory<?> getInstance(Class<?> clazz) throws AsterixException {
          try {
              return (IRecordReaderFactory<?>) clazz.getDeclaredConstructor().newInstance();
          } catch (InstantiationException | IllegalAccessException | ClassCastException | NoSuchMethodException
                  | InvocationTargetException e) {
              throw new AsterixException("Cannot create: " + clazz.getSimpleName(), e);
          }
      }
  
      public static IRecordReaderFactory<?> getRecordReaderFactory(String adaptorName, Map<String, String> configuration)
              throws HyracksDataException, AsterixException {
          if (adaptorName.equals(ExternalDataConstants.EXTERNAL)) {
              //return ExternalDataUtils.createExternalRecordReaderFactory(libraryManager, configuration);
              throw new NotImplementedException();
          }
  
          initFactories();
  
          if (factories.containsKey(adaptorName)) {
              Map<String, Class<?>> formatClassMap = factories.get(adaptorName);
              String format = configuration.get(ExternalDataConstants.KEY_FORMAT);
              if (isDeltaTable(configuration)) {
                  format = configuration.get(ExternalDataConstants.TABLE_FORMAT);
                  return getInstance(formatClassMap.getOrDefault(format, formatClassMap.get(DEFAULT_FORMAT)));
              }
              return getInstance(formatClassMap.getOrDefault(format, formatClassMap.get(DEFAULT_FORMAT)));
          }
  
          try {
              return (IRecordReaderFactory<?>) Class.forName(adaptorName).getDeclaredConstructor().newInstance();
          } catch (IllegalAccessException | ClassNotFoundException | InstantiationException | ClassCastException
                  | NoSuchMethodException | InvocationTargetException e) {
              throw new RuntimeDataException(ErrorCode.UNKNOWN_RECORD_READER_FACTORY, e, adaptorName);
          }
      }
  
      protected static synchronized void initFactories() throws AsterixException {
          if (factories != null) {
              return;
          }
          factories = new HashMap<>();
          ClassLoader cl = ParserFactoryProvider.class.getClassLoader();
          final Charset encoding = StandardCharsets.UTF_8;
          try {
              Enumeration<URL> urls = cl.getResources(RESOURCE);
              for (URL url : Collections.list(urls)) {
                  InputStream is = url.openStream();
                  String config = IOUtils.toString(is, encoding);
                  is.close();
                  String[] classNames = config.split("\n");
                  for (String className : classNames) {
                      if (className.startsWith("#")) {
                          continue;
                      }
                      final Class<?> clazz = Class.forName(className);
                      final IRecordReaderFactory<?> readerFactory =
                              (IRecordReaderFactory<?>) clazz.getDeclaredConstructor().newInstance();
                      List<String> readerNames = readerFactory.getRecordReaderNames();
                      Set<String> supportedFormats = readerFactory.getReaderSupportedFormats();
                      putFactory(readerNames, supportedFormats, clazz);
                  }
              }
          } catch (IOException | ClassNotFoundException | InstantiationException | IllegalAccessException
                  | NoSuchMethodException | InvocationTargetException e) {
              throw new AsterixException(e);
          }
      }
  
      private static void putFactory(List<String> readerNames, Set<String> supportedFormats, Class<?> clazz)
              throws AsterixException {
          for (String reader : readerNames) {
              Map<String, Class<?>> formatClassMap = factories.computeIfAbsent(reader, k -> new HashMap<>());
              if (isDefaultFormat(supportedFormats)) {
                  //Ensure that only one reader is the default reader
                  checkDuplicates(formatClassMap, DEFAULT_FORMAT);
                  formatClassMap.put(DEFAULT_FORMAT, clazz);
              } else {
                  //Specialized formats for the same reader name
                  for (String format : supportedFormats) {
                      checkDuplicates(formatClassMap, format);
                      formatClassMap.put(format, clazz);
                  }
              }
          }
      }
  
      private static boolean isDefaultFormat(Set<String> supportedFormats) {
          return supportedFormats.equals(ExternalDataConstants.ALL_FORMATS);
      }
  
      private static void checkDuplicates(Map<String, Class<?>> factories, String key) throws AsterixException {
          if (factories.containsKey(key)) {
              throw new AsterixException(ErrorCode.PROVIDER_DATASOURCE_FACTORY_DUPLICATE_FORMAT_MAPPING, key);
          }
      }
  }
  