1 /* 2 * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package jdk.nashorn.api.scripting; 27 28 import java.io.CharArrayReader; 29 import java.io.IOException; 30 import java.io.Reader; 31 import java.net.URL; 32 import java.nio.charset.Charset; 33 import java.util.Objects; 34 import jdk.nashorn.internal.runtime.Source; 35 36 /** 37 * A Reader that reads from a URL. Used to make sure that the reader 38 * reads content from given URL and can be trusted to do so. 39 * 40 * @since 1.8u40 41 */ 42 public final class URLReader extends Reader { 43 // underlying URL 44 private final URL url; 45 // Charset used to convert 46 private final Charset cs; 47 48 // lazily initialized underlying reader for URL 49 private Reader reader; 50 51 /** 52 * Constructor 53 * 54 * @param url URL for this URLReader 55 * @throws NullPointerException if url is null 56 */ 57 public URLReader(final URL url) { 58 this(url, (Charset)null); 59 } 60 61 /** 62 * Constructor 63 * 64 * @param url URL for this URLReader 65 * @param charsetName Name of the Charset used to convert bytes to chars 66 * @throws NullPointerException if url is null 67 */ 68 public URLReader(final URL url, final String charsetName) { 69 this(url, Charset.forName(charsetName)); 70 } 71 72 /** 73 * Constructor 74 * 75 * @param url URL for this URLReader 76 * @param cs Charset used to convert bytes to chars 77 * @throws NullPointerException if url is null 78 */ 79 public URLReader(final URL url, final Charset cs) { 80 this.url = Objects.requireNonNull(url); 81 this.cs = cs; 82 } 83 84 @Override 85 public int read(final char cbuf[], final int off, final int len) throws IOException { 86 return getReader().read(cbuf, off, len); 87 } 88 89 @Override 90 public void close() throws IOException { 91 getReader().close(); 92 } 93 94 /** 95 * URL of this reader 96 * @return the URL from which this reader reads. 97 */ 98 public URL getURL() { 99 return url; 100 } 101 102 /** 103 * Charset used by this reader 104 * 105 * @return the Charset used to convert bytes to chars 106 */ 107 public Charset getCharset() { 108 return cs; 109 } 110 111 // lazily initialize char array reader using URL content 112 private Reader getReader() throws IOException { 113 synchronized (lock) { 114 if (reader == null) { 115 reader = new CharArrayReader(Source.readFully(url, cs)); 116 } 117 } 118 119 return reader; 120 } 121 }