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