FileReaderProvider.java

/*
 * 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
 *
 *   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.streams.test.component;

import org.apache.streams.core.StreamsDatum;
import org.apache.streams.core.StreamsProvider;
import org.apache.streams.core.StreamsResultSet;

import org.joda.time.DateTime;

import java.math.BigInteger;
import java.util.Queue;
import java.util.Scanner;
import java.util.concurrent.LinkedBlockingQueue;

/**
 * FOR TESTING PURPOSES ONLY.
 *
 * The StreamProvider reads from a File or InputStream.  Each line of the file will be emitted as the document of a
 * streams datum.
 *
 */
public class FileReaderProvider implements StreamsProvider {

  private String fileName;
  private Scanner scanner;
  private StreamsDatumConverter converter;

  public FileReaderProvider(String filePathInResources, StreamsDatumConverter converter) {
    this.fileName = filePathInResources;
    this.converter = converter;
  }

  @Override
  public String getId() {
    return "FileReaderProvider";
  }

  @Override
  public void startStream() {

  }

  @Override
  public StreamsResultSet readCurrent() {
    return new StreamsResultSet(constructQueue(this.scanner));
  }

  @Override
  public StreamsResultSet readNew(BigInteger sequence) {
    throw new UnsupportedOperationException();
  }

  @Override
  public StreamsResultSet readRange(DateTime start, DateTime end) {
    throw new UnsupportedOperationException();
  }

  @Override
  public boolean isRunning() {
    return this.scanner != null && this.scanner.hasNextLine();
  }

  @Override
  public void prepare(Object configurationObject) {
    this.scanner = new Scanner(FileReaderProvider.class.getResourceAsStream(this.fileName));
  }

  @Override
  public void cleanUp() {
    if(this.scanner!= null) {
      this.scanner.close();
      this.scanner = null;
    }
  }

  private Queue<StreamsDatum> constructQueue(Scanner scanner) {
    Queue<StreamsDatum> data = new LinkedBlockingQueue<>();
    while(scanner.hasNextLine()) {
      data.add(converter.convert(scanner.nextLine()));
    }
    cleanUp();
    return data;
  }
}