001/*
002 * nimbus-jose-jwt
003 *
004 * Copyright 2012-2016, Connect2id Ltd and contributors.
005 *
006 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use
007 * this file except in compliance with the License. You may obtain a copy of the
008 * License at
009 *
010 *    http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software distributed
013 * under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
014 * CONDITIONS OF ANY KIND, either express or implied. See the License for the
015 * specific language governing permissions and limitations under the License.
016 */
017
018package com.nimbusds.jose.util;
019
020
021import java.io.*;
022import java.nio.charset.Charset;
023
024
025/**
026 * Input / output utilities.
027 *
028 * @author Vladimir Dzhuvinov
029 * @version 2019-11-07
030 */
031public class IOUtils {
032        
033        
034        /**
035         * Reads the specified input stream into a string.
036         *
037         * @param stream  The input stream. Must not be {@code null}.
038         * @param charset The expected character set. Must not be {@code null}.
039         *
040         * @return The string.
041         *
042         * @throws IOException If an input exception is encountered.
043         */
044        public static String readInputStreamToString(final InputStream stream, final Charset charset)
045                throws IOException {
046                
047                final int bufferSize = 1024;
048                final char[] buffer = new char[bufferSize];
049                final StringBuilder out = new StringBuilder();
050                
051                Reader in = new InputStreamReader(stream, charset);
052                try {
053                        while (true) {
054                                int rsz = in.read(buffer, 0, buffer.length);
055                                if (rsz < 0)
056                                        break;
057                                out.append(buffer, 0, rsz);
058                        }
059                        return out.toString();
060                } finally {
061                        in.close();
062                }
063        }
064        
065        
066        /**
067         * Reads the content of the specified file into a string.
068         *
069         * @param file    The file. Must not be {@code null}.
070         * @param charset The expected character set. Must not be {@code null}.
071         *
072         * @return The string.
073         *
074         * @throws IOException If an input exception is encountered.
075         */
076        public static String readFileToString(final File file, final Charset charset)
077                throws IOException {
078                
079                return readInputStreamToString(new FileInputStream(file), charset);
080        }
081        
082        
083        /**
084         * Prevents public instantiation.
085         */
086        private IOUtils() {}
087}