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 @jdk.Exported 43 public final class URLReader extends Reader { 44 // underlying URL 45 private final URL url; 46 // Charset used to convert 47 private final Charset cs; 48 49 // lazily initialized underlying reader for URL 50 private Reader reader; 51 52 /** 53 * Constructor 54 * 55 * @param url URL for this URLReader 56 * @throws NullPointerException if url is null 57 */ 58 public URLReader(final URL url) { 59 this(url, (Charset)null); 60 } 61 62 /** 63 * Constructor 64 * 65 * @param url URL for this URLReader 66 * @param charsetName Name of the Charset used to convert bytes to chars 67 * @throws NullPointerException if url is null 68 */ 69 public URLReader(final URL url, final String charsetName) { 70 this(url, Charset.forName(charsetName)); 71 } 72 73 /** 74 * Constructor 75 * 76 * @param url URL for this URLReader 77 * @param cs Charset used to convert bytes to chars 78 * @throws NullPointerException if url is null 79 */ 80 public URLReader(final URL url, final Charset cs) { 81 this.url = Objects.requireNonNull(url); 82 this.cs = cs; 83 } 84 85 @Override 86 public int read(final char cbuf[], final int off, final int len) throws IOException { 87 return getReader().read(cbuf, off, len); 88 } 89 90 @Override 91 public void close() throws IOException { 92 getReader().close(); 93 } 94 95 /** 96 * URL of this reader 97 * @return the URL from which this reader reads. 98 */ 99 public URL getURL() { 100 return url; 101 } 102 103 /** 104 * Charset used by this reader 105 * 106 * @return the Charset used to convert bytes to chars 107 */ 108 public Charset getCharset() { 109 return cs; 110 } 111 112 // lazily initialize char array reader using URL content 113 private Reader getReader() throws IOException { 114 synchronized (lock) { 115 if (reader == null) { 116 reader = new CharArrayReader(Source.readFully(url, cs)); 117 } 118 } 119 120 return reader; 121 } 122 }