Package org.opentrafficsim.base.compressedfiles

Class Reader

java.lang.Object
org.opentrafficsim.base.compressedfiles.Reader
public final class Reader
extends java.lang.Object
Reader for compressed files.

Copyright (c) 2013-2019 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved.
BSD-style license. See OpenTrafficSim License.

Version:
$Revision$, $LastChangedDate$, by $Author$, initial version Oct 25, 2018
Author:
Alexander Verbraeck, Peter Knoppers, Wouter Schakel

  • Method Summary

    Modifier and Type Method Description
    static CompressionType autoDetectCompressionType​(java.lang.String fileName)
    Determine the type of compression used in a file.
    static java.io.InputStream createInputStream​(java.lang.String fileName)
    Construct a InputStream for a compressed data file.
    static java.io.InputStream createInputStream​(java.lang.String fileName, CompressionType compressionType)
    Construct a InputStream for a compressed data file.
    static boolean isGZipCompressed​(byte[] bytes)
    Determine if bytes match the GZip compression signature.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Method Details

    • createInputStream

      public static java.io.InputStream createInputStream​(java.lang.String fileName, CompressionType compressionType) throws java.io.IOException
      Construct a InputStream for a compressed data file.
      Parameters:
      fileName - String; the name of the file
      compressionType - CompressionType; the expected type of the data compression in the file
      Returns:
      InputStream that can yield the expanded content of the file.
      Throws:
      java.io.IOException - when the file could not be read

    • createInputStream

      public static java.io.InputStream createInputStream​(java.lang.String fileName) throws java.io.IOException
      Construct a InputStream for a compressed data file. The type of compression is auto-detected.
      Parameters:
      fileName - String; the name of the file
      Returns:
      InputStream that can yield the expanded content of the file.
      Throws:
      java.io.IOException - when the file can not be opened or read

    • autoDetectCompressionType

      public static CompressionType autoDetectCompressionType​(java.lang.String fileName) throws java.io.IOException
      Determine the type of compression used in a file.

      Derived from http://stackoverflow.com/questions/4818468/how-to-check-if-inputstream-is-gzipped.
      Gzip inflate an inputStream (if it is indeed gzip compressed), otherwise return an InputStream that yields the same data as the input argument.

      Parameters:
      fileName - String; the name of the file to check
      Returns:
      InputStream yielding the inflated data
      Throws:
      java.io.IOException - when errors occur reading the signature bytes

    • isGZipCompressed

      public static boolean isGZipCompressed​(byte[] bytes) throws java.io.IOException
      Determine if bytes match the GZip compression signature. Derived from http://stackoverflow.com/questions/4818468/how-to-check-if-inputstream-is-gzipped.
      Determines if a byte array is compressed. The java.util.zip GZip implementation does not expose the GZip header so it is difficult to determine if a string is compressed.
      Parameters:
      bytes - byte[]; at least 2 bytes from the start of the stream to determine compression type
      Returns:
      boolean; true if the data appears to be GZip compressed; false otherwise
      Throws:
      java.io.IOException - if the byte array couldn't be read