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  */

    25 package jdk.jshell.execution;

    26 

    27 import java.io.IOException;

    28 import java.io.OutputStream;

    29 import java.io.UnsupportedEncodingException;

    30 

    31 /**

    32  * Packetize an OutputStream, dividing it into named channels.

    33  *

    34  * @author Jan Lahoda

    35  */

    36 class 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 }