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Java > Open Source Codes > org > apache > james > util > ExtraDotOutputStream


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5  * Licensed under the Apache License, Version 2.0 (the "License"); you *
6  * may not use this file except in compliance with the License. You *
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9  * http://www.apache.org/licenses/LICENSE-2.0 *
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14  * implied. See the License for the specific language governing *
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17
18 package org.apache.james.util;
19
20 import java.io.FilterOutputStream JavaDoc;
21 import java.io.IOException JavaDoc;
22 import java.io.OutputStream JavaDoc;
23
24 /**
25  * Adds extra dot if dot occurs in message body at beginning of line (according to RFC1939)
26  * Compare also org.apache.james.smtpserver.SMTPInputStream
27  */
28 public class ExtraDotOutputStream extends FilterOutputStream JavaDoc {
29
30     /*
31     static public void main(String[] args) throws IOException
32     {
33         String data = ".This is a test\r\nof the thing.\r\nWe should not have much trouble.\r\n.doubled?\r\nor not?\n.doubled\nor not?\r\n\r\n\n\n\r\r\r\n";
34
35         OutputStream os = new ExtraDotOutputStream(System.out);
36         os.write(data.getBytes());
37     }
38     */
39
40     /**
41      * Counter for number of last (0A or 0D).
42      */
43     protected int countLast0A0D;
44
45     /**
46      * Constructor that wraps an OutputStream.
47      *
48      * @param out the OutputStream to be wrapped
49      */
50     public ExtraDotOutputStream(OutputStream JavaDoc out) {
51         super(out);
52         countLast0A0D = 2; // we already assume a CRLF at beginning (otherwise TOP would not work correctly !)
53 }
54
55     /**
56      * Writes a byte to the stream, adding dots where appropriate.
57      * Also fixes any naked CR or LF to the RFC 2821 mandated CFLF
58      * pairing.
59      *
60      * @param b the byte to write
61      *
62      * @throws IOException if an error occurs writing the byte
63      */
64     public void write(int b) throws IOException JavaDoc {
65         switch (b) {
66             case '.':
67                 if (countLast0A0D == 2) {
68                     // add extra dot (the first of the pair)
69 out.write('.');
70                 }
71                 countLast0A0D = 0;
72                 break;
73             case '\r':
74                 if (countLast0A0D == 1) out.write('\n'); // two CR in a row, so insert an LF first
75 countLast0A0D = 1;
76                 break;
77             case '\n':
78                 /* RFC 2821 #2.3.7 mandates that line termination is
79                  * CRLF, and that CR and LF must not be transmitted
80                  * except in that pairing. If we get a naked LF,
81                  * convert to CRLF.
82                  */
83                 if (countLast0A0D != 1) out.write('\r');
84                 countLast0A0D = 2;
85                 break;
86             default:
87                 // we're no longer at the start of a line
88 countLast0A0D = 0;
89                 break;
90         }
91         out.write(b);
92     }
93 }
94
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