corba/src/share/classes/org/omg/DynamicAny/package.html - edge/openjdk - Git at Google

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 <P>Provides classes and interfaces that enable traversal of the data value
  associated with an <code>any</code> at
 runtime, and extraction of the primitive constituents of the data value.


 <P>An <code>any</code> can be passed to a program that doesn't have any static information
 for the type of the <code>any</code> (code generated for the type by an IDL compiler has not
 been compiled with the object implementation). As a result, the object receiving the
 <code>any</code> does not have a portable method of using it.

 <P><code>DynAny</code>s enable traversal of the data value associated with an
 <code>any</code> at runtime, and extraction of the primitive constituents of the data value.
 This is especially helpful for writing powerful generic servers (bridges, event channels
 supporting filtering).  Similarly, this facility enables the construction of an
 <code>any</code> at runtime, without having static knowledge of its type. This is especially
 helpful for writing generic clients (bridges, browsers, debuggers, user interface tools).

 <P><code>Any</code> values can be dynamically interpreted (traversed) and constructed through
 <tt>DynAny</tt> objects.  A <tt>DynAny</tt> object is associated with a data
 value which corresponds to a copy of the value inserted into an <tt>Any</tt>.  A
 <tt>DynAny</tt> object may be viewed as an ordered collection of component
 <tt>DynAny</tt>s. For <tt>DynAny</tt>s representing a basic type, such as <code>long</code>,
 or a type without components, such as an empty exception, the ordered collection of
 components is empty.

 <P>Each <tt>DynAny</tt> object maintains the notion of a current position into its collection
 of component <tt>DynAny</tt>s. The current position is identified by an index value that runs
 from 0 to n-1, where <em>n</em> is the number of components.  The special index value -1
 indicates a current position that points nowhere.
  For values that cannot have a current position (such as an empty exception),
  the index value is fixed at -1.
  If a <code>DynAny</code> is initialized with a value that has components, the index is
 initialized to 0.
  After creation of an uninitialized <code>DynAny</code> (that is, a <code>DynAny</code> that
 has no value but a <code>TypeCode</code>
  that permits components), the current position depends on the type of value represented by
  the <code>DynAny</code>. (The current position is set to 0 or -1, depending on whether the
 new <code>DynAny</code>
  gets default values for its components.)


  <P>The iteration operations <code>rewind</code>, <code>seek</code>, and <code>next</code>
 can be used to change the current position
  and the <code>current_component</code> operation returns the component at the current
 position.
  The <code>component_count</code> operation returns the number of components of a
 <code>DynAny</code>.
  Collectively, these operations enable iteration over the components of a
 <code>DynAny</code>, for example,
  to (recursively) examine its contents.


  <P>A constructed <code>DynAny</code> object is a <code>DynAny</code> object associated with
 a constructed type.
  There is a different interface, inheriting from the <code>DynAny</code> interface,
 associated with
  each kind of constructed type in IDL (fixed, enum, struct, sequence, union, array,
  exception, and value type).  A constructed <code>DynAny</code> object exports operations
 that enable the creation of new <code>DynAny</code> objects,
  each of them associated with a component of the constructed data value.
  As an example, a <code>DynStruct</code> is associated with a <code>struct</code> value. This
 means that the <code>DynStruct</code>
  may be seen as owning an ordered collection of components, one for each structure member.
  The <code>DynStruct</code> object exports operations that enable the creation of new
 <code>DynAny</code> objects,
  each of them associated with a member of the <code>struct</code>.


  <P>If a <code>DynAny</code> object has been obtained from another (constructed)
 <code>DynAny</code> object,
  such as a <code>DynAny</code> representing a structure member that was created from a
 <code>DynStruct</code>,
  the member <code>DynAny</code> is logically contained in the <code>DynStruct</code>.
  Calling an <code>insert</code> or <code>get</code> operation leaves the current position
 unchanged.
  Destroying a top-level <code>DynAny</code> object (one that was not obtained as a component
 of another <code>DynAny</code>)
  also destroys any component <code>DynAny</code> objects obtained from it.
  Destroying a non-top level <code>DynAny</code> object does nothing.
  Invoking operations on a destroyed top-level <code>DynAny</code> or any of its descendants
 raises OBJECT_NOT_EXIST.
  If the programmer wants to destroy a <code>DynAny</code> object but still wants to
 manipulate some component
  of the data value associated with it, then he or she should first create a
 <code>DynAny</code> for the component
  and, after that, make a copy of the created <code>DynAny</code> object.


  <P>The behavior of <code>DynAny</code> objects has been defined in order to enable efficient
 implementations
  in terms of allocated memory space and speed of access. <code>DynAny</code> objects are
 intended to be used
  for traversing values extracted from <code>any</code>s or constructing values of
 <code>any</code>s at runtime.
  Their use for other purposes is not recommended.


  <H2>Handling DynAny objects</H2>

  <P><code>Insert</code> and <code>get</code> operations are necessary to handle basic
 <code>DynAny</code> objects
  but are also helpful to handle constructed <code>DynAny</code> objects.
  Inserting a basic data type value into a constructed <code>DynAny</code> object
  implies initializing the current component of the constructed data value
  associated with the <code>DynAny</code> object. For example, invoking
 <code>insert_boolean</code> on a
  <code>DynStruct</code> implies inserting a <code>boolean</code> data value at the current
 position
  of the associated <code>struct</code> data value.
  A type is consistent for inserting or extracting a value if its <code>TypeCode</code> is
 equivalent to
  the <code>TypeCode</code> contained in the <code>DynAny</code> or, if the
 <code>DynAny</code> has components, is equivalent to the <code>TypeCode</code>
  of the <code>DynAny</code> at the current position.

  <P>Basic operations include:
  <P>
  <UL>
  	<LI>insert_boolean, get_boolean
  	<LI>insert_char, get_char
  	<LI>insert_short, get_short
  	<LI>insert_ushort, get_ushort
  	<LI>insert_long, get_long
  	<LI>insert_ulong, get_ulong
  	<LI>insert_double, get_double
  	<LI>insert_string, get_string
  	<LI>insert_reference, get_reference
  	<LI>insert_typecode, get_typecode
  	<LI>insert_longlong, get_longlong
  	<LI>insert_ulonglong, get_ulonglong
  	<LI>insert_longdouble, get_longdouble
  	<LI>insert_wchar, get_wchar
  	<LI>insert_wstring, get_wstring
  	<LI>insert_any, get_any
  	<LI>insert_dyn_any, get_dyn_any
  	<LI>insert_val, get_val
  	<LI>insert_octet, get_octet
  	<LI>insert_float, get_float
  	<LI>get_value
  	<LI>get_as_string
  	<LI>get_as_ulong
  	<LI>get_members
  	<LI>get_members_as_dyn_any
  	<LI>get_discriminator
  	<LI>get_length
  	<LI>get_elements
  	<LI>get_elements_as_dyn_any
  	<LI>get_boxed_value
  	<LI>get_boxed_value_as_dyn_any
  </UL>


  <P><code>DynAny</code> and <code>DynAnyFactory</code> objects are intended to be local to
 the process in which they are
  created and used. This means that references to <code>DynAny</code> and
 <code>DynAnyFactory</code> objects cannot be exported
  to other processes, or externalized with <code>ORB.object_to_string()</code>.
  If any attempt is made to do so, the offending operation will raise a MARSHAL system
 exception.
  Since their interfaces are specified in IDL, <code>DynAny</code> objects export operations
 defined in the standard
  <code>org.omg.CORBA.Object</code> interface. However, any attempt to invoke operations
 exported through the <code>Object</code>
  interface may raise the standard NO_IMPLEMENT exception.
  An attempt to use a <code>DynAny</code> object with the DII may raise the NO_IMPLEMENT
 exception.


 <P>


 <H3>Package Specification</H3>

 <P>For a precise list of supported sections of official specifications with which
 the Java[tm] Platform, Standard Edition 6 ORB complies, see <A
 HREF="../CORBA/doc-files/compliance.html">Official Specifications for CORBA
 support in Java[tm] SE 6</A>.
 <p>
 @since 1.4
 <br>
 @serial exclude
 </body>
 </html>
	<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
	<html>
	<head>
	<!--

	Copyright (c) 2000, 2006, Oracle and/or its affiliates. All rights reserved.
	DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

	This code is free software; you can redistribute it and/or modify it
	under the terms of the GNU General Public License version 2 only, as
	published by the Free Software Foundation. Oracle designates this
	particular file as subject to the "Classpath" exception as provided
	by Oracle in the LICENSE file that accompanied this code.

	This code is distributed in the hope that it will be useful, but WITHOUT
	ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	version 2 for more details (a copy is included in the LICENSE file that
	accompanied this code).

	You should have received a copy of the GNU General Public License version
	2 along with this work; if not, write to the Free Software Foundation,
	Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

	Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	or visit www.oracle.com if you need additional information or have any
	questions.

	-->

	</head>
	<body bgcolor="white">
	<P>Provides classes and interfaces that enable traversal of the data value
	associated with an <code>any</code> at
	runtime, and extraction of the primitive constituents of the data value.


	<P>An <code>any</code> can be passed to a program that doesn't have any static information
	for the type of the <code>any</code> (code generated for the type by an IDL compiler has not
	been compiled with the object implementation). As a result, the object receiving the
	<code>any</code> does not have a portable method of using it.

	<P><code>DynAny</code>s enable traversal of the data value associated with an
	<code>any</code> at runtime, and extraction of the primitive constituents of the data value.
	This is especially helpful for writing powerful generic servers (bridges, event channels
	supporting filtering). Similarly, this facility enables the construction of an
	<code>any</code> at runtime, without having static knowledge of its type. This is especially
	helpful for writing generic clients (bridges, browsers, debuggers, user interface tools).

	<P><code>Any</code> values can be dynamically interpreted (traversed) and constructed through
	<tt>DynAny</tt> objects. A <tt>DynAny</tt> object is associated with a data
	value which corresponds to a copy of the value inserted into an <tt>Any</tt>. A
	<tt>DynAny</tt> object may be viewed as an ordered collection of component
	<tt>DynAny</tt>s. For <tt>DynAny</tt>s representing a basic type, such as <code>long</code>,
	or a type without components, such as an empty exception, the ordered collection of
	components is empty.

	<P>Each <tt>DynAny</tt> object maintains the notion of a current position into its collection
	of component <tt>DynAny</tt>s. The current position is identified by an index value that runs
	from 0 to n-1, where <em>n</em> is the number of components. The special index value -1
	indicates a current position that points nowhere.
	For values that cannot have a current position (such as an empty exception),
	the index value is fixed at -1.
	If a <code>DynAny</code> is initialized with a value that has components, the index is
	initialized to 0.
	After creation of an uninitialized <code>DynAny</code> (that is, a <code>DynAny</code> that
	has no value but a <code>TypeCode</code>
	that permits components), the current position depends on the type of value represented by
	the <code>DynAny</code>. (The current position is set to 0 or -1, depending on whether the
	new <code>DynAny</code>
	gets default values for its components.)


	<P>The iteration operations <code>rewind</code>, <code>seek</code>, and <code>next</code>
	can be used to change the current position
	and the <code>current_component</code> operation returns the component at the current
	position.
	The <code>component_count</code> operation returns the number of components of a
	<code>DynAny</code>.
	Collectively, these operations enable iteration over the components of a
	<code>DynAny</code>, for example,
	to (recursively) examine its contents.


	<P>A constructed <code>DynAny</code> object is a <code>DynAny</code> object associated with
	a constructed type.
	There is a different interface, inheriting from the <code>DynAny</code> interface,
	associated with
	each kind of constructed type in IDL (fixed, enum, struct, sequence, union, array,
	exception, and value type). A constructed <code>DynAny</code> object exports operations
	that enable the creation of new <code>DynAny</code> objects,
	each of them associated with a component of the constructed data value.
	As an example, a <code>DynStruct</code> is associated with a <code>struct</code> value. This
	means that the <code>DynStruct</code>
	may be seen as owning an ordered collection of components, one for each structure member.
	The <code>DynStruct</code> object exports operations that enable the creation of new
	<code>DynAny</code> objects,
	each of them associated with a member of the <code>struct</code>.


	<P>If a <code>DynAny</code> object has been obtained from another (constructed)
	<code>DynAny</code> object,
	such as a <code>DynAny</code> representing a structure member that was created from a
	<code>DynStruct</code>,
	the member <code>DynAny</code> is logically contained in the <code>DynStruct</code>.
	Calling an <code>insert</code> or <code>get</code> operation leaves the current position
	unchanged.
	Destroying a top-level <code>DynAny</code> object (one that was not obtained as a component
	of another <code>DynAny</code>)
	also destroys any component <code>DynAny</code> objects obtained from it.
	Destroying a non-top level <code>DynAny</code> object does nothing.
	Invoking operations on a destroyed top-level <code>DynAny</code> or any of its descendants
	raises OBJECT_NOT_EXIST.
	If the programmer wants to destroy a <code>DynAny</code> object but still wants to
	manipulate some component
	of the data value associated with it, then he or she should first create a
	<code>DynAny</code> for the component
	and, after that, make a copy of the created <code>DynAny</code> object.


	<P>The behavior of <code>DynAny</code> objects has been defined in order to enable efficient
	implementations
	in terms of allocated memory space and speed of access. <code>DynAny</code> objects are
	intended to be used
	for traversing values extracted from <code>any</code>s or constructing values of
	<code>any</code>s at runtime.
	Their use for other purposes is not recommended.



	<H2>Handling DynAny objects</H2>

	<P><code>Insert</code> and <code>get</code> operations are necessary to handle basic
	<code>DynAny</code> objects
	but are also helpful to handle constructed <code>DynAny</code> objects.
	Inserting a basic data type value into a constructed <code>DynAny</code> object
	implies initializing the current component of the constructed data value
	associated with the <code>DynAny</code> object. For example, invoking
	<code>insert_boolean</code> on a
	<code>DynStruct</code> implies inserting a <code>boolean</code> data value at the current
	position
	of the associated <code>struct</code> data value.
	A type is consistent for inserting or extracting a value if its <code>TypeCode</code> is
	equivalent to
	the <code>TypeCode</code> contained in the <code>DynAny</code> or, if the
	<code>DynAny</code> has components, is equivalent to the <code>TypeCode</code>
	of the <code>DynAny</code> at the current position.

	<P>Basic operations include:
	<P>
	<UL>
	<LI>insert_boolean, get_boolean
	<LI>insert_char, get_char
	<LI>insert_short, get_short
	<LI>insert_ushort, get_ushort
	<LI>insert_long, get_long
	<LI>insert_ulong, get_ulong
	<LI>insert_double, get_double
	<LI>insert_string, get_string
	<LI>insert_reference, get_reference
	<LI>insert_typecode, get_typecode
	<LI>insert_longlong, get_longlong
	<LI>insert_ulonglong, get_ulonglong
	<LI>insert_longdouble, get_longdouble
	<LI>insert_wchar, get_wchar
	<LI>insert_wstring, get_wstring
	<LI>insert_any, get_any
	<LI>insert_dyn_any, get_dyn_any
	<LI>insert_val, get_val
	<LI>insert_octet, get_octet
	<LI>insert_float, get_float
	<LI>get_value
	<LI>get_as_string
	<LI>get_as_ulong
	<LI>get_members
	<LI>get_members_as_dyn_any
	<LI>get_discriminator
	<LI>get_length
	<LI>get_elements
	<LI>get_elements_as_dyn_any
	<LI>get_boxed_value
	<LI>get_boxed_value_as_dyn_any
	</UL>


	<P><code>DynAny</code> and <code>DynAnyFactory</code> objects are intended to be local to
	the process in which they are
	created and used. This means that references to <code>DynAny</code> and
	<code>DynAnyFactory</code> objects cannot be exported
	to other processes, or externalized with <code>ORB.object_to_string()</code>.
	If any attempt is made to do so, the offending operation will raise a MARSHAL system
	exception.
	Since their interfaces are specified in IDL, <code>DynAny</code> objects export operations
	defined in the standard
	<code>org.omg.CORBA.Object</code> interface. However, any attempt to invoke operations
	exported through the <code>Object</code>
	interface may raise the standard NO_IMPLEMENT exception.
	An attempt to use a <code>DynAny</code> object with the DII may raise the NO_IMPLEMENT
	exception.






	<P>


	<H3>Package Specification</H3>

	<P>For a precise list of supported sections of official specifications with which
	the Java[tm] Platform, Standard Edition 6 ORB complies, see <A
	HREF="../CORBA/doc-files/compliance.html">Official Specifications for CORBA
	support in Java[tm] SE 6</A>.
	<p>
	@since 1.4
	<br>
	@serial exclude
	</body>
	</html>