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 jdk.nashorn.internal.runtime.Source; 34 35 /** 36 * A Reader that reads from a URL. Used to make sure that the reader 37 * reads content from given URL and can be trusted to do so. 38 */ 39 public final class URLReader extends Reader { 40 // underlying URL 41 private final URL url; 42 // Charset used to convert 43 private final Charset cs; 44 45 // lazily initialized underlying reader for URL 46 private Reader reader; 47 48 /** 49 * Constructor 50 * 51 * @param url URL for this URLReader 52 * @throws NullPointerException if url is null 53 */ 54 public URLReader(final URL url) { 55 this(url, (Charset)null); 56 } 57 58 /** 59 * Constructor 60 * 61 * @param url URL for this URLReader 62 * @param charsetName Name of the Charset used to convert bytes to chars 63 * @throws NullPointerException if url is null 64 */ 65 public URLReader(final URL url, final String charsetName) { 66 this(url, Charset.forName(charsetName)); 67 } 68 69 /** 70 * Constructor 71 * 72 * @param url URL for this URLReader 73 * @param cs Charset used to convert bytes to chars 74 * @throws NullPointerException if url is null 75 */ 76 public URLReader(final URL url, final Charset cs) { 77 // null check 78 url.getClass(); 79 this.url = url; 80 this.cs = cs; 81 } 82 83 @Override 84 public int read(final char cbuf[], final int off, final int len) throws IOException { 85 return getReader().read(cbuf, off, len); 86 } 87 88 @Override 89 public void close() throws IOException { 90 getReader().close(); 91 } 92 93 /** 94 * URL of this reader 95 * @return the URL from which this reader reads. 96 */ 97 public URL getURL() { 98 return url; 99 } 100 101 /** 102 * Charset used by this reader 103 * 104 * @return the Chartset used to convert bytes to chars 105 */ 106 public Charset getCharset() { 107 return cs; 108 } 109 110 // lazily initialize char array reader using URL content 111 private Reader getReader() throws IOException { 112 synchronized (lock) { 113 if (reader == null) { 114 reader = new CharArrayReader(Source.readFully(url, cs)); 115 } 116 } 117 118 return reader; 119 } 120 }