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Stanford CoreNLP provides a set of natural language analysis tools which can take raw English language text input and give the base forms of words, their parts of speech, whether they are names of companies, people, etc., normalize dates, times, and numeric quantities, mark up the structure of sentences in terms of phrases and word dependencies, and indicate which noun phrases refer to the same entities. It provides the foundational building blocks for higher level text understanding applications.

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package edu.stanford.nlp.objectbank;

import java.io.*;
import java.util.*;

import java.util.function.Function;
import edu.stanford.nlp.util.AbstractIterator;


/**
 * An Iterator that returns a line of a file at a time.
 * Lines are broken as determined by Java's readLine() method.
 * The returned lines do not include the newline character.
 *
 * @author Christopher Manning
 */
public class LineIterator extends AbstractIterator {

  private final Function op;
  private final BufferedReader in;
  private X nextToken; // = null;

  @SuppressWarnings({"unchecked"})
  public LineIterator(Reader r) {
    this(r, new IdentityFunction());  // it seems like this can't be generified: seems a weird brokenness of Java to me! [cdm]
  }

  public LineIterator(Reader r, Function op) {
    this.op = op;
    in = new BufferedReader(r);
    setNext();
  }

  private void setNext() {
    String line = null;
    try {
      line = in.readLine();
    } catch (IOException ioe) {
      ioe.printStackTrace();
    }
    if (line != null) {
      nextToken = op.apply(line);
    } else {
      nextToken = null;
    }
  }

  @Override
  public boolean hasNext() {
    return nextToken != null;
  }

  @Override
  public X next() {
    if (nextToken == null) {
      throw new NoSuchElementException("LineIterator reader exhausted");
    }
    X token = nextToken;
    setNext();

    return token;
  }

  public Object peek() {
    return nextToken;
  }

  /**
   * Returns a factory that vends LineIterators that read the contents of the
   * given Reader, splitting on newlines.
   *
   * @return An iterator over the lines of a file
   */
  public static  IteratorFromReaderFactory getFactory() {
    return new LineIteratorFactory<>();
  }

  /**
   * Returns a factory that vends LineIterators that read the contents of the
   * given Reader, splitting on newlines.
   *
   * @param op A function to be applied to each line before it is returned
   * @return An iterator over the lines of a file
   */
  public static  IteratorFromReaderFactory getFactory(Function op) {
    return new LineIteratorFactory<>(op);
  }


  public static class LineIteratorFactory implements IteratorFromReaderFactory, Serializable {

    private static final long serialVersionUID = 1L;

    @SuppressWarnings({"NonSerializableFieldInSerializableClass"})
    private final Function function;

    @SuppressWarnings({"unchecked"})
    public LineIteratorFactory() {
      this(new IdentityFunction());  // it seems like this can't be generified: seems a weird brokenness of Java to me! [cdm]
    }

    public LineIteratorFactory(Function op) {
      this.function = op;
    }

    @Override
    public Iterator getIterator(Reader r) {
      return new LineIterator<>(r, function);
    }

  }

}