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  33 <P>Provides classes and interfaces that enable traversal of the data value
  34  associated with an <code>any</code> at
  35 runtime, and extraction of the primitive constituents of the data value.
  38 <P>An <code>any</code> can be passed to a program that doesn't have any static information 
  39 for the type of the <code>any</code> (code generated for the type by an IDL compiler has not 
  40 been compiled with the object implementation). As a result, the object receiving the 
  41 <code>any</code> does not have a portable method of using it.
  43 <P><code>DynAny</code>s enable traversal of the data value associated with an
  44 <code>any</code> at runtime, and extraction of the primitive constituents of the data value.
  45 This is especially helpful for writing powerful generic servers (bridges, event channels
  46 supporting filtering).  Similarly, this facility enables the construction of an
  47 <code>any</code> at runtime, without having static knowledge of its type. This is especially
  48 helpful for writing generic clients (bridges, browsers, debuggers, user interface tools).
  50 <P><code>Any</code> values can be dynamically interpreted (traversed) and constructed through
  51 <code>DynAny</code> objects.  A <code>DynAny</code> object is associated with a data
  52 value which corresponds to a copy of the value inserted into an <code>Any</code>.  A
  53 <code>DynAny</code> object may be viewed as an ordered collection of component 
  54 <code>DynAny</code>s. For <code>DynAny</code>s representing a basic type, such as <code>long</code>,
  55 or a type without components, such as an empty exception, the ordered collection of
  56 components is empty.
  58 <P>Each <code>DynAny</code> object maintains the notion of a current position into its collection
  59 of component <code>DynAny</code>s. The current position is identified by an index value that runs
  60 from 0 to n-1, where <em>n</em> is the number of components.  The special index value -1
  61 indicates a current position that points nowhere.
  62  For values that cannot have a current position (such as an empty exception),
  63  the index value is fixed at -1.
  64  If a <code>DynAny</code> is initialized with a value that has components, the index is
  65 initialized to 0.
  66  After creation of an uninitialized <code>DynAny</code> (that is, a <code>DynAny</code> that
  67 has no value but a <code>TypeCode</code>
  68  that permits components), the current position depends on the type of value represented by
  69  the <code>DynAny</code>. (The current position is set to 0 or -1, depending on whether the
  70 new <code>DynAny</code>
  71  gets default values for its components.)
  74 <P>The iteration operations <code>rewind</code>, <code>seek</code>, and <code>next</code>
  75 can be used to change the current position
  76  and the <code>current_component</code> operation returns the component at the current
  77 position.
  78  The <code>component_count</code> operation returns the number of components of a
  79 <code>DynAny</code>.
  80  Collectively, these operations enable iteration over the components of a
  81 <code>DynAny</code>, for example,
  82  to (recursively) examine its contents.
  85  <P>A constructed <code>DynAny</code> object is a <code>DynAny</code> object associated with
  86 a constructed type.
  87  There is a different interface, inheriting from the <code>DynAny</code> interface,
  88 associated with
  89  each kind of constructed type in IDL (fixed, enum, struct, sequence, union, array,
  90  exception, and value type).  A constructed <code>DynAny</code> object exports operations
  91 that enable the creation of new <code>DynAny</code> objects,
  92  each of them associated with a component of the constructed data value.
  93  As an example, a <code>DynStruct</code> is associated with a <code>struct</code> value. This
  94 means that the <code>DynStruct</code>
  95  may be seen as owning an ordered collection of components, one for each structure member.
  96  The <code>DynStruct</code> object exports operations that enable the creation of new
  97 <code>DynAny</code> objects,
  98  each of them associated with a member of the <code>struct</code>.
 101 <P>If a <code>DynAny</code> object has been obtained from another (constructed)
 102 <code>DynAny</code> object,
 103  such as a <code>DynAny</code> representing a structure member that was created from a
 104 <code>DynStruct</code>,
 105  the member <code>DynAny</code> is logically contained in the <code>DynStruct</code>.
 106  Calling an <code>insert</code> or <code>get</code> operation leaves the current position
 107 unchanged.
 108  Destroying a top-level <code>DynAny</code> object (one that was not obtained as a component
 109 of another <code>DynAny</code>)
 110  also destroys any component <code>DynAny</code> objects obtained from it.
 111  Destroying a non-top level <code>DynAny</code> object does nothing.
 112  Invoking operations on a destroyed top-level <code>DynAny</code> or any of its descendants
 113 raises OBJECT_NOT_EXIST.
 114  If the programmer wants to destroy a <code>DynAny</code> object but still wants to
 115 manipulate some component
 116  of the data value associated with it, then he or she should first create a
 117 <code>DynAny</code> for the component
 118  and, after that, make a copy of the created <code>DynAny</code> object.
 121 <P>The behavior of <code>DynAny</code> objects has been defined in order to enable efficient
 122 implementations
 123 in terms of allocated memory space and speed of access. <code>DynAny</code> objects are
 124 intended to be used
 125 for traversing values extracted from <code>any</code>s or constructing values of
 126 <code>any</code>s at runtime.
 127 Their use for other purposes is not recommended.
 131  <H2>Handling DynAny objects</H2>
 133 <P><code>Insert</code> and <code>get</code> operations are necessary to handle basic 
 134 <code>DynAny</code> objects
 135  but are also helpful to handle constructed <code>DynAny</code> objects.
 136  Inserting a basic data type value into a constructed <code>DynAny</code> object
 137  implies initializing the current component of the constructed data value
 138  associated with the <code>DynAny</code> object. For example, invoking 
 139 <code>insert_boolean</code> on a
 140  <code>DynStruct</code> implies inserting a <code>boolean</code> data value at the current 
 141 position
 142  of the associated <code>struct</code> data value.
 143  A type is consistent for inserting or extracting a value if its <code>TypeCode</code> is 
 144 equivalent to
 145  the <code>TypeCode</code> contained in the <code>DynAny</code> or, if the 
 146 <code>DynAny</code> has components, is equivalent to the <code>TypeCode</code>
 147  of the <code>DynAny</code> at the current position.
 149  <P>Basic operations include:
 150  <UL>
 151         <LI>insert_boolean, get_boolean
 152         <LI>insert_char, get_char
 153         <LI>insert_short, get_short
 154         <LI>insert_ushort, get_ushort
 155         <LI>insert_long, get_long
 156         <LI>insert_ulong, get_ulong
 157         <LI>insert_double, get_double
 158         <LI>insert_string, get_string
 159         <LI>insert_reference, get_reference
 160         <LI>insert_typecode, get_typecode
 161         <LI>insert_longlong, get_longlong
 162         <LI>insert_ulonglong, get_ulonglong
 163         <LI>insert_longdouble, get_longdouble
 164         <LI>insert_wchar, get_wchar
 165         <LI>insert_wstring, get_wstring
 166         <LI>insert_any, get_any
 167         <LI>insert_dyn_any, get_dyn_any
 168         <LI>insert_val, get_val
 169         <LI>insert_octet, get_octet
 170         <LI>insert_float, get_float
 171         <LI>get_value
 172         <LI>get_as_string
 173         <LI>get_as_ulong
 174         <LI>get_members
 175         <LI>get_members_as_dyn_any
 176         <LI>get_discriminator
 177         <LI>get_length
 178         <LI>get_elements
 179         <LI>get_elements_as_dyn_any
 180         <LI>get_boxed_value
 181         <LI>get_boxed_value_as_dyn_any
 182  </UL>
 185  <P><code>DynAny</code> and <code>DynAnyFactory</code> objects are intended to be local to
 186 the process in which they are
 187  created and used. This means that references to <code>DynAny</code> and
 188 <code>DynAnyFactory</code> objects cannot be exported
 189  to other processes, or externalized with <code>ORB.object_to_string()</code>.
 190  If any attempt is made to do so, the offending operation will raise a MARSHAL system
 191 exception.
 192  Since their interfaces are specified in IDL, <code>DynAny</code> objects export operations
 193 defined in the standard
 194  <code>org.omg.CORBA.Object</code> interface. However, any attempt to invoke operations
 195 exported through the <code>Object</code>
 196  interface may raise the standard NO_IMPLEMENT exception.
 197  An attempt to use a <code>DynAny</code> object with the DII may raise the NO_IMPLEMENT
 198 exception.
 200 <H3>Package Specification</H3>
 202 <P>For a precise list of supported sections of official specifications with which
 203 the Java[tm] Platform, Standard Edition 6 ORB complies, see <A
 204 HREF="../CORBA/doc-files/compliance.html">Official Specifications for CORBA
 205 support in Java[tm] SE 6</A>.
 207 @since 1.4
 208 <br>
 209 @serial exclude
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