ConsolePersistReader.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.console;

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

import org.joda.time.DateTime;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.InputStream;
import java.math.BigInteger;
import java.util.Queue;
import java.util.Scanner;
import java.util.concurrent.ConcurrentLinkedQueue;

/**
 * ConsolePersistReader reads documents from stdin.
 */
public class ConsolePersistReader implements StreamsPersistReader {

  private static final String STREAMS_ID = "ConsolePersistReader";

  private static final Logger LOGGER = LoggerFactory.getLogger(ConsolePersistReader.class);

  protected volatile Queue<StreamsDatum> persistQueue;

  protected InputStream inputStream = System.in;

  public ConsolePersistReader() {
    this.persistQueue = new ConcurrentLinkedQueue<StreamsDatum>();
  }

  public ConsolePersistReader(InputStream inputStream) {
    this();
    this.inputStream = inputStream;
  }

  @Override
  public String getId() {
    return STREAMS_ID;
  }

  public void prepare(Object configuration) {

  }

  public void cleanUp() {

  }

  @Override
  public void startStream() {
    // no op
  }

  @Override
  public StreamsResultSet readAll() {
    return readCurrent();
  }

  @Override
  public StreamsResultSet readCurrent() {

    LOGGER.info("{} readCurrent", STREAMS_ID);

    Scanner sc = new Scanner(inputStream);

    while ( sc.hasNextLine() ) {

      persistQueue.offer(new StreamsDatum(sc.nextLine()));

    }

    LOGGER.info("Providing {} docs", persistQueue.size());

    StreamsResultSet result =  new StreamsResultSet(persistQueue);

    LOGGER.info("{} Exiting", STREAMS_ID);

    return result;

  }

  @Override
  public StreamsResultSet readNew(BigInteger sequence) {
    return readCurrent();
  }

  @Override
  public StreamsResultSet readRange(DateTime start, DateTime end) {
    return readCurrent();
  }

  @Override
  public boolean isRunning() {
    return true;  //Will always be running
  }
}