ServiceContext.java revision 608:7e06bf1dcb09 
1/*
2 * Copyright (c) 1998, 2013, 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
26package com.sun.corba.se.spi.servicecontext;
27
28import org.omg.CORBA.SystemException;
29import org.omg.CORBA.INTERNAL;
30import org.omg.CORBA_2_3.portable.InputStream ;
31import org.omg.CORBA_2_3.portable.OutputStream ;
32import com.sun.corba.se.spi.ior.iiop.GIOPVersion;
33import com.sun.corba.se.spi.orb.ORB ;
34import com.sun.corba.se.impl.encoding.CDRInputStream ;
35import com.sun.corba.se.impl.encoding.EncapsInputStream ;
36import com.sun.corba.se.impl.encoding.EncapsOutputStream ;
37import com.sun.corba.se.impl.orbutil.ORBUtility ;
38
39/** Base class for all ServiceContext classes.
40* There is a derived ServiceContext class for each service context that
41* the ORB supports.  Each subclass encapsulates the representation of
42* the service context and provides any needed methods for manipulating
43* the service context.  Each subclass must provide the following
44* members:
45* <p>
46* <ul>
47* </li>a public static final int SERVICE_CONTEXT_ID that gives the OMG
48* (or other) defined id for the service context.  This is needed for the
49* registration mechanism defined in ServiceContexts. OMG defined
50* service context ids are taken from section 13.6.7 of ptc/98-12-04.</li>
51* <li>a public constructor that takes an InputStream as its argument.</li>
52* <li>Appropriate definitions of getId() and writeData().  getId() must
53* return SERVICE_CONTEXT_ID.</li>
54* </ul>
55* <p>
56* The subclass can be constructed either directly from the service context
57* representation, or by reading the representation from an input stream.
58* These cases are needed when the service context is created and written to
59* the request or reply, and when the service context is read from the
60* received request or reply.
61*/
62public abstract class ServiceContext {
63    /** Simple default constructor used when subclass is constructed
64     * from its representation.
65     */
66    protected ServiceContext() { }
67
68    private void dprint( String msg )
69    {
70        ORBUtility.dprint( this, msg ) ;
71    }
72
73    /** Stream constructor used when subclass is constructed from an
74     * InputStream.  This constructor must be called by super( stream )
75     * in the subclass.  After this constructor completes, the service
76     * context representation can be read from in.
77     * Note that the service context id has been consumed from the input
78     * stream before this object is constructed.
79     */
80    protected ServiceContext(InputStream s, GIOPVersion gv) throws SystemException
81    {
82        in = s;
83    }
84
85    /** Returns Service context id.  Must be overloaded in subclass.
86     */
87    public abstract int getId() ;
88
89    /** Write the service context to an output stream.  This method
90     * must be used for writing the service context to a request or reply
91     * header.
92     */
93    public void write(OutputStream s, GIOPVersion gv) throws SystemException
94    {
95        EncapsOutputStream os =
96            sun.corba.OutputStreamFactory.newEncapsOutputStream((ORB)(s.orb()), gv);
97        os.putEndian() ;
98        writeData( os ) ;
99        byte[] data = os.toByteArray() ;
100
101        s.write_long(getId());
102        s.write_long(data.length);
103        s.write_octet_array(data, 0, data.length);
104    }
105
106    /** Writes the data used to represent the subclasses service context
107     * into an encapsulation stream.  Must be overloaded in subclass.
108     */
109    protected abstract void writeData( OutputStream os ) ;
110
111    /** in is the stream containing the service context representation.
112     * It is constructed by the stream constructor, and available for use
113     * in the subclass stream constructor.
114     */
115    protected InputStream in = null ;
116
117    public String toString()
118    {
119        return "ServiceContext[ id=" + getId() + " ]" ;
120    }
121}
122