1 /*

     2  * Copyright (c) 2002-2016, the original author or authors.

     3  *

     4  * This software is distributable under the BSD license. See the terms of the

     5  * BSD license in the documentation provided with this software.

     6  *

     7  * http://www.opensource.org/licenses/bsd-license.php

     8  */

     9 package jdk.internal.jline.console.internal;

    10 

    11 import jdk.internal.jline.console.ConsoleReader;

    12 

    13 import java.io.IOException;

    14 import java.io.InputStream;

    15 import java.io.SequenceInputStream;

    16 import java.util.Enumeration;

    17 

    18 // FIXME: Clean up API and move to jline.console.runner package

    19 

    20 /**

    21  * An {@link InputStream} implementation that wraps a {@link ConsoleReader}.

    22  * It is useful for setting up the {@link System#in} for a generic console.

    23  *

    24  * @author <a href="mailto:mwp1@cornell.edu">Marc Prud'hommeaux</a>

    25  * @since 2.7

    26  */

    27 class ConsoleReaderInputStream

    28     extends SequenceInputStream

    29 {

    30     private static InputStream systemIn = System.in;

    31 

    32     public static void setIn() throws IOException {

    33         setIn(new ConsoleReader());

    34     }

    35 

    36     public static void setIn(final ConsoleReader reader) {

    37         System.setIn(new ConsoleReaderInputStream(reader));

    38     }

    39 

    40     /**

    41      * Restore the original {@link System#in} input stream.

    42      */

    43     public static void restoreIn() {

    44         System.setIn(systemIn);

    45     }

    46 

    47     public ConsoleReaderInputStream(final ConsoleReader reader) {

    48         super(new ConsoleEnumeration(reader));

    49     }

    50 

    51     private static class ConsoleEnumeration

    52         implements Enumeration<InputStream>

    53     {

    54         private final ConsoleReader reader;

    55         private ConsoleLineInputStream next = null;

    56         private ConsoleLineInputStream prev = null;

    57 

    58         public ConsoleEnumeration(final ConsoleReader reader) {

    59             this.reader = reader;

    60         }

    61 

    62         public InputStream nextElement() {

    63             if (next != null) {

    64                 InputStream n = next;

    65                 prev = next;

    66                 next = null;

    67 

    68                 return n;

    69             }

    70 

    71             return new ConsoleLineInputStream(reader);

    72         }

    73 

    74         public boolean hasMoreElements() {

    75             // the last line was null

    76             if ((prev != null) && (prev.wasNull == true)) {

    77                 return false;

    78             }

    79 

    80             if (next == null) {

    81                 next = (ConsoleLineInputStream) nextElement();

    82             }

    83 

    84             return next != null;

    85         }

    86     }

    87 

    88     private static class ConsoleLineInputStream

    89         extends InputStream

    90     {

    91         private final ConsoleReader reader;

    92         private String line = null;

    93         private int index = 0;

    94         private boolean eol = false;

    95         protected boolean wasNull = false;

    96 

    97         public ConsoleLineInputStream(final ConsoleReader reader) {

    98             this.reader = reader;

    99         }

   100 

   101         public int read() throws IOException {

   102             if (eol) {

   103                 return -1;

   104             }

   105 

   106             if (line == null) {

   107                 line = reader.readLine();

   108             }

   109 

   110             if (line == null) {

   111                 wasNull = true;

   112                 return -1;

   113             }

   114 

   115             if (index >= line.length()) {

   116                 eol = true;

   117                 return '\n'; // lines are ended with a newline

   118             }

   119 

   120             return line.charAt(index++);

   121         }

   122     }

   123 }