Class Files

corpus/java/training/guava/io/Files.java:65–856

Provides utility methods for working with files. All method parameters must be non-null unless documented otherwise. @author Chris Nokleberg @author Colin Decker @since 1.0

 * @since 1.0
 */
@Beta
@GwtIncompatible
public final class Files {

  /** Maximum loop count when creating temp directories. */
  private static final int TEMP_DIR_ATTEMPTS = 10000;

  private Files() {}

  /**
   * Returns a buffered reader that reads from a file using the given character set.
   *
   * @param file the file to read from
   * @param charset the charset used to decode the input stream; see {@link StandardCharsets} for
   *     helpful predefined constants
   * @return the buffered reader
   */
  public static BufferedReader newReader(File file, Charset charset) throws FileNotFoundException {
    checkNotNull(file);
    checkNotNull(charset);
    return new BufferedReader(new InputStreamReader(new FileInputStream(file), charset));
  }

  /**
   * Returns a buffered writer that writes to a file using the given character set.
   *
   * @param file the file to write to
   * @param charset the charset used to encode the output stream; see {@link StandardCharsets} for
   *     helpful predefined constants
   * @return the buffered writer
   */
  public static BufferedWriter newWriter(File file, Charset charset) throws FileNotFoundException {
    checkNotNull(file);
    checkNotNull(charset);
    return new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file), charset));
  }

  /**
   * Returns a new {@link ByteSource} for reading bytes from the given file.
   *
   * @since 14.0
   */
  public static ByteSource asByteSource(File file) {
    return new FileByteSource(file);
  }

  private static final class FileByteSource extends ByteSource {

    private final File file;

    private FileByteSource(File file) {
      this.file = checkNotNull(file);
    }

    @Override
    public FileInputStream openStream() throws IOException {
      return new FileInputStream(file);
    }