1. /*

  2.  * @(#)ContextList.java	1.20 00/02/02

  3.  *

  4.  * Copyright 1996-2000 Sun Microsystems, Inc. All Rights Reserved.

  5.  * 

  6.  * This software is the proprietary information of Sun Microsystems, Inc.  

  7.  * Use is subject to license terms.

  8.  * 

  9.  */

  10. 

  11. package org.omg.CORBA;

  12. 

  13. /**

  14.  * An object containing a modifiable list of <code>String</code> objects

  15.  * that represent property names.

  16.  * This class is used in <code>Request</code> operations to

  17.  * describe the contexts that need to be resolved and sent with the

  18.  * invocation.  (A context is resolved by giving a property name

  19.  * and getting back the value associated with it.)  This is done

  20.  * by calling the <code>Context</code> method

  21.  * <code>get_values</code> and supplying a string from a

  22.  * <code>ContextList</code> object as the third parameter.

  23.  * The method <code>get_values</code> returns an <code>NVList</code>

  24.  * object containing the <code>NamedValue</code> objects that hold

  25.  * the value(s) identified by the given string.

  26.  * <P>

  27.  * A <code>ContextList</code> object is created by the ORB, as

  28.  * illustrated here:

  29.  * <PRE>

  30.  *   ORB orb = ORB.init(args, null);

  31.  *   org.omg.CORBA.ContextList ctxList = orb.create_context_list();

  32.  * </PRE>

  33.  * The variable <code>ctxList</code> represents an empty

  34.  * <code>ContextList</code> object.  Strings are added to

  35.  * the list with the method <code>add</code>, accessed

  36.  * with the method <code>item</code>, and removed with the

  37.  * method <code>remove</code>.

  38.  *

  39.  * @see Context

  40.  * @version 1.2, 09/09/97

  41.  * @since   JDK1.2

  42.  */

  43. 

  44. public abstract class ContextList {

  45. 

  46.     /**

  47.      * Returns the number of <code>String</code> objects in this

  48.      * <code>ContextList</code> object.

  49.      *

  50.      * @return			an <code>int</code> representing the number of

  51.      * <code>String</code>s in this <code>ContextList</code> object

  52.      */

  53. 

  54.     public abstract int count();

  55. 

  56.     /**

  57.      * Adds a <code>String</code> object to this <code>ContextList</code>

  58.      * object.

  59.      *

  60.      * @param ctx		the <code>String</code> object to be added

  61.      */

  62. 

  63.     public abstract void add(String ctx);

  64. 

  65.     /**

  66.      * Returns the <code>String</code> object at the given index.

  67.      *

  68.      * @param index		the index of the string desired, with 0 being the

  69.      index of the first string

  70.      * @return			the string at the given index

  71.      * @exception org.omg.CORBA.Bounds  if the index is greater than

  72.      *				or equal to the number of strings in this

  73.      *                <code>ContextList</code> object

  74.      */

  75. 

  76.     public abstract String item(int index) throws org.omg.CORBA.Bounds;

  77. 

  78.     /**

  79.      * Removes the <code>String</code> object at the given index. Note that

  80.      * the indices of all strings following the one removed are

  81.      * shifted down by one.

  82.      *

  83.      * @param index	the index of the <code>String</code> object to be removed,

  84.      *                with 0 designating the first string

  85.      * @exception org.omg.CORBA.Bounds  if the index is greater than

  86.      *				or equal to the number of <code>String</code> objects in

  87.      *                this <code>ContextList</code> object

  88.      */

  89. 

  90.     public abstract void remove(int index) throws org.omg.CORBA.Bounds;

  91. 

  92. }