com.rapiddweller.common.ReaderLineIterator Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of rd-lib-common Show documentation

'rapiddweller Common' is an open source Java library forked from Databene Commons by Volker Bergmann. It provides extensions to the Java core library by utility classes, abstract concepts and concrete implementations.

There is a newer version: 2.0.1-jdk-11

Show newest version

/*
 * Copyright (C) 2004-2015 Volker Bergmann ([email protected]).
 * 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.
 */

package com.rapiddweller.common;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.Reader;

/**
 * Iterator implementation that returns text lines provided by a reader.
 * Created: 01.05.2007 08:06:46
 *
 * @author Volker Bergmann
 * @since 0.1
 */
public class ReaderLineIterator implements HeavyweightIterator {

  private BufferedReader reader;
  private final boolean skipEmptyLines;
  private String next;

  private int lineCount;

  /**
   * Instantiates a new Reader line iterator.
   *
   * @param reader the reader
   */
  public ReaderLineIterator(Reader reader) {
    this(reader, false);
  }

  /**
   * Instantiates a new Reader line iterator.
   *
   * @param reader         the reader
   * @param skipEmptyLines the skip empty lines
   */
  public ReaderLineIterator(Reader reader, boolean skipEmptyLines) {
    if (reader instanceof BufferedReader) {
      this.reader = (BufferedReader) reader;
    } else {
      this.reader = new BufferedReader(reader);
    }
    this.skipEmptyLines = skipEmptyLines;
    this.lineCount = 0;
    fetchNext();
  }

  @Override
  public void close() {
    if (reader != null) {
      IOUtil.close(reader);
      reader = null;
    }
  }

  /**
   * Line count int.
   *
   * @return the int
   */
  public int lineCount() {
    return lineCount;
  }

  // Iterator interface ----------------------------------------------------------------------------------------------

  @Override
  public boolean hasNext() {
    return reader != null && next != null;
  }

  @Override
  public String next() {
    String result = next;
    fetchNext();
    return result;
  }

  @Override
  public void remove() {
    throw new UnsupportedOperationException("Not supported");
  }

  // helpers ---------------------------------------------------------------------------------------------------------

  private void fetchNext() {
    try {
      if (reader != null) {
        do {
          next = reader.readLine();
        } while (skipEmptyLines && next != null && next.trim().length() == 0);
        if (next == null) {
          close();
        }
        lineCount++;
      } else {
        next = null;
      }
    } catch (IOException e) {
      throw new RuntimeException(e);
    }
  }

}