Here you can find the source of getReader(String filename)
public static Reader getReader(String filename) throws IOException
//package com.java2s; /**File: UtilLib.java /*from w w w .j a v a 2 s . com*/ Original Author: Sven Schuierer Date: 04/01/2012 Copyright 2015 Novartis Institutes for BioMedical Research Inc.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. */ import java.io.*; import java.util.zip.*; public class Main { /*********************************************************************************** * * getReader * ***********************************************************************************/ public static Reader getReader(String filename) throws IOException { if (filename == "") { return null; } if (filename.equals("-")) { return new BufferedReader(new InputStreamReader(System.in)); } File inputFile = new File(filename); if (!inputFile.exists()) { throw new IOException("Warning: file " + filename + " not found."); } if (!inputFile.canRead()) { throw new IOException("Warning: file " + filename + " cannot be read."); } if (filename.endsWith(".gz")) { return new InputStreamReader(new GZIPInputStream(new FileInputStream(inputFile))); } return new FileReader(inputFile); } }