1/* 2 * Copyright (c) 2016, 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 */ 25package jdk.jshell.execution; 26 27import java.io.IOException; 28import java.io.OutputStream; 29import java.io.UnsupportedEncodingException; 30 31/** 32 * Packetize an OutputStream, dividing it into named channels. 33 * 34 * @author Jan Lahoda 35 */ 36class MultiplexingOutputStream extends OutputStream { 37 38 private static final int PACKET_SIZE = 127; 39 private final byte[] name; 40 private final OutputStream delegate; 41 42 MultiplexingOutputStream(String name, OutputStream delegate) { 43 try { 44 this.name = name.getBytes("UTF-8"); 45 this.delegate = delegate; 46 } catch (UnsupportedEncodingException ex) { 47 throw new IllegalStateException(ex); //should not happen 48 } 49 } 50 51 @Override 52 public void write(int b) throws IOException { 53 write(new byte[] {(byte) b}); 54 } 55 56 @Override 57 public void write(byte[] b, int off, int len) throws IOException { 58 synchronized (delegate) { 59 int i = 0; 60 while (len > 0) { 61 int size = Math.min(PACKET_SIZE, len); 62 byte[] data = new byte[name.length + 1 + size + 1]; 63 data[0] = (byte) name.length; //assuming the len is small enough to fit into byte 64 System.arraycopy(name, 0, data, 1, name.length); 65 data[name.length + 1] = (byte) size; 66 System.arraycopy(b, off + i, data, name.length + 2, size); 67 delegate.write(data); 68 i += size; 69 len -= size; 70 } 71 delegate.flush(); 72 } 73 } 74 75 @Override 76 public void flush() throws IOException { 77 super.flush(); 78 delegate.flush(); 79 } 80 81 @Override 82 public void close() throws IOException { 83 super.close(); 84 delegate.close(); 85 } 86 87} 88