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 eu.amidst.core.datastream.filereaders;
  
  import eu.amidst.core.datastream.Attributes;
  import eu.amidst.core.datastream.DataInstance;
  import eu.amidst.core.datastream.DataOnMemory;
  
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.List;
  import java.util.stream.Stream;
  
  /**
   * This class implements the interface {@link DataOnMemory} and produces {@link DataOnMemory} objects from a given file.
   */
  public class DataOnMemoryFromFile implements DataOnMemory<DataInstance> {
  
      /** Represents the {@link DataFileReader} object providing access to the data stored in a file. */
      private DataFileReader reader;
  
      /**
       * Represents an Array of data instances.
       * <p>The data is assumed here to be relatively small, and thus it would be possible to be read multiple times.
       * In this case, it is possible to store all the data instances in an Array. Otherwise, it might be better to store all
       * the data instances in an ArrayList and avoid therefore the extra pass in the constructor.</p>
       */
      private DataInstanceFromDataRow[] dataInstances;
  
      /**
       * Creates a new DataOnMemoryFromFile from a given {@link DataFileReader} object.
       * @param reader a {@link DataFileReader} object.
       */
      public DataOnMemoryFromFile(DataFileReader reader) {
          this.reader = reader;
  
          List<DataInstanceFromDataRow> dataInstancesList = new ArrayList<>();
  
          for (DataRow row: reader){
              dataInstancesList.add(new DataInstanceFromDataRow(row));
          }
          reader.restart();
  
          dataInstances = new DataInstanceFromDataRow[dataInstancesList.size()];
          int counter = 0;
          for (DataInstanceFromDataRow inst : dataInstancesList) {
              dataInstances[counter] = inst;
              counter++;
          }
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public int getNumberOfDataInstances() {
          return dataInstances.length;
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public DataInstance getDataInstance(int i) {
          return dataInstances[i];
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public List<DataInstance> getList() {
          return Arrays.asList(this.dataInstances);
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public Attributes getAttributes() {
          return this.reader.getAttributes();
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public Stream<DataInstance> stream() {
          return Arrays.stream(this.dataInstances);
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public void close() {
          this.reader.close();
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public boolean isRestartable() {
          return true;
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public void restart() {
  
      }
  }