code: /*
   *
   * Copyright (c) 2008, All Rights Reserved.
   *
   * Licensed 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.
   *
   * Portions of the code may be copied from Google Collections
   * or Apache Commons projects.
   */
  
  package zemberek.core.io;
  
  import com.google.common.base.Preconditions;
  import java.io.BufferedReader;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.Reader;
  import java.util.ArrayList;
  import java.util.Iterator;
  import java.util.List;
  import java.util.NoSuchElementException;
  
  /**
   * An Iterator over the lines in a <code>Reader</code>.
   * <p/>
   * <code>LineIterator</code> holds a reference to an open <code>Reader</code>. if there hasNext()
   * returns false, it automatically closes the reader. if somewhat an early return is possible
   * iterator or the reader should be closed by calling {@link #close()} method.
   * <p/>
   * The recommended usage pattern is:
   * <pre>
   * ;
   * try(LineIterator it = new LineIterator(Files.getReader("filename", "UTF-8"))) {
   *   while (it.hasNext()) {
   *     String line = it.next();
   *     /// do something with line
   *   }
   * }
   * </pre>
   * <p/>
   * This class uses code from Apache commons io LineIterator class. however, it's behavior is
   * slightly different.
   */
  public class LineIterator implements Iterator<String>, AutoCloseable {
  
    private final BufferedReader bufferedReader;
    /**
     * The current line.
     */
    private String cachedLine;
    /**
     * A flag indicating if the iterator has been fully read.
     */
    private boolean finished = false;
  
    private boolean trim = false;
  
    private List<Filter<String>> filters = new ArrayList<>();
  
    public LineIterator(InputStream is) {
      Preconditions.checkNotNull(is, "InputStream cannot be null!");
      this.bufferedReader = IOs.getReader(is);
    }
  
    public LineIterator(Reader reader) {
      Preconditions.checkNotNull(reader, "Reader cannot be null!");
      if (reader instanceof BufferedReader) {
        this.bufferedReader = (BufferedReader) reader;
      } else {
        this.bufferedReader = new BufferedReader(reader);
      }
    }
  
    public LineIterator(Reader reader, boolean trim,List<Filter<String>> filters) {
      Preconditions.checkNotNull(reader, "Reader cannot be null!");
      if (reader instanceof BufferedReader) {
        this.bufferedReader = (BufferedReader) reader;
      } else {
        this.bufferedReader = new BufferedReader(reader);
      }
      this.filters = new ArrayList<>(filters);
  
      this.trim = trim;
    }
  
    public boolean hasNext() {
      if (cachedLine != null) {
        return true;
      } else if (finished) {
        close();
        return false;
      } else {
        try {
          String line;
          do {
            line = bufferedReader.readLine();
            if (line != null && trim) {
              line = line.trim();
            }
          }
          while (line != null && filters.size() > 0 && !StringFilters.canPassAll(line, filters));
  
          if (line == null) {
            finished = true;
            close();
            return false;
          } else {
            cachedLine = line;
            return true;
          }
        } catch (IOException ioe) {
          close();
          throw new IllegalStateException(ioe.toString());
        }
      }
    }
  
    public String next() {
      if (!hasNext()) {
        close();
        throw new NoSuchElementException("No more lines");
      }
      String currentLine = cachedLine;
      cachedLine = null;
      return currentLine;
    }
  
    public void remove() {
      throw new UnsupportedOperationException("remove() is not implemented in LineIterator class.");
    }
  
    public void close() {
      IOs.closeSilently(bufferedReader);
    }
  }
  