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27 
28 package com.sun.star.lib.uno.environments.remote;
29 
30 import com.sun.star.lib.uno.typedesc.TypeDescription;
31 import java.io.IOException;
32 
33 /**
34  * An abstraction of remote bridge protocols.
35  *
36  * <p>A class implementing a given protocol <var>prot</var> must be named
37  * <code>com.sun.star.lib.uno.protocols.<var>prot</var>.<var>prot</var></code>
38  * and must have a public constructor that takes four arguments:  The first
39  * argument of type <code>com.sun.star.uno.IBridge</code> must not be null.  The
40  * second argument of type <code>String</code> represents any attributes; it may
41  * be null if there are no attributes.  The third argument of type
42  * <code>java.io.InputStream</code> must not be null.  The fourth argument of
43  * type <code>java.io.OutputStream</code> must not be null.</p>
44  */
45 public interface IProtocol {
46     /**
47      * Initializes the connection.
48      *
49      * <p>This method must be called exactly once, after the
50      * <code>readMessage</code> loop has already been established.</p>
51      */
52     void init() throws IOException;
53 
54     void terminate();
55 
56     /**
57      * Reads a request or reply message.
58      *
59      * <p>Access to this method from multiple threads must be properly
60      * synchronized.</p>
61      *
62      * @return a non-null message; if the input stream is exhausted, a
63      *     <code>java.io.IOException</code> is thrown instead
64      */
65     Message readMessage() throws IOException;
66 
67     /**
68      * Writes a request message.
69      *
70      * @param oid a non-null OID
71      * @param type a non-null UNO type
72      * @param function a non-null function (the name of a UNO interface method
73      *     or attribute compatible with the given <code>type</code>, or either
74      *     <code>"queryInterface"</code> or <code>"release"</code>)
75      * @param threadId a non-null TID
76      * @param arguments a list of UNO arguments compatible with the given
77      *     <code>type</code> and <code>function</code>; may be null to represent
78      *     an empty list
79      * @return <code>true</code> if the request message is sent as a synchronous
80      *     request
81      */
82     boolean writeRequest(
83         String oid, TypeDescription type, String function, ThreadId tid,
84         Object[] arguments)
85         throws IOException;
86 
87     /**
88      * Writes a reply message.
89      *
90      * @param exception <code>true</code> if the reply corresponds to a raised
91      *     exception
92      * @param tid a non-null TID
93      * @param result if <code>exception</code> is <code>true</code>, a non-null
94      *     UNO exception; otherwise, a UNO return value, which may be null to
95      *     represent a <code>VOID</code> return value
96      */
97     void writeReply(boolean exception, ThreadId tid, Object result)
98         throws IOException;
99 }
100