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Class org.omg.CORBA.ORB

java.lang.Object
  |
  +--org.omg.CORBA.ORB

public abstract class ORB

extends Object

A class providing APIs for the CORBA Object Request Broker features. The ORB class also provides "pluggable ORB implementation" APIs that allow another vendor's ORB implementation to be used.

An ORB makes it possible for CORBA objects to communicate with each other by connecting objects making requests (clients) with objects servicing requests (servers).

The ORB class, which encapsulates generic CORBA functionality, does the following: (Note that items 5 and 6, which include most of the methods in the class ORB, are typically used with the Dynamic Invocation Interface (DII) and the Dynamic Skeleton Interface (DSI). These interfaces may be used by a developer directly, but most commonly they are used by the ORB internally and are not seen by the general programmer.)

1. initializes the ORB implementation by supplying values for predefined properties and environmental parameters
2. obtains initial object references to services such as the NameService using the method resolve_initial_references
3. converts object references to strings and back
4. connects the ORB to a servant (an instance of a CORBA object implementation) and disconnects the ORB from a servant
5. creates objects such as
   • TypeCode
   • Any
   • NamedValue
   • Context
   • Environment
   • lists (such as NVList) containing these objects
6. sends multiple messages in the DII

The ORB class can be used to obtain references to objects implemented anywhere on the network.

An application or applet gains access to the CORBA environment by initializing itself into an ORB using one of three init methods. Two of the three methods use the properties (associations of a name with a value) shown in the table below.

Standard Java CORBA Properties:

Property Name	Property Value
org.omg.CORBA.ORBClass	class name of an ORB implementation
org.omg.CORBA.ORBSingletonClass	class name of the ORB returned by init()

These properties allow a different vendor's ORB implementation to be "plugged in."

When an ORB instance is being created, the class name of the ORB implementation is located using the following standard search order:

1. check in Applet parameter or application string array, if any
2. check in properties parameter, if any
3. check in the System properties (currently applications only)
4. fall back on a hardcoded default behavior (use the Java IDL implementation)

Note that Java IDL provides a default implementation for the fully-functional ORB and for the Singleton ORB. When the method init is given no parameters, the default Singleton ORB is returned. When the method init is given parameters but no ORB class is specified, the Java IDL ORB implementation is returned.

The following code fragment creates an ORB object initialized with the default ORB Singleton. This ORB has a restricted implementation to prevent malicious applets from doing anything beyond creating typecodes. It is called a singleton because there is only one instance for an entire virtual machine.

    ORB orb = ORB.init();
 

The following code fragment creates an ORB object for an application. The parameter args represents the arguments supplied to the application's main method. Since the property specifies the ORB class to be "SomeORBImplementation", the new ORB will be initialized with that ORB implementation. If p had been null, and the arguments had not specified an ORB class, the new ORB would have been initialized with the default Java IDL implementation.

    Properties p = new Properties();
    p.put("org.omg.CORBA.ORBClass", "SomeORBImplementation");
    ORB orb = ORB.init(args, p);
 

The following code fragment creates an ORB object for the applet supplied as the first parameter. If the given applet does not specify an ORB class, the new ORB will be initialized with the default Java IDL implementation.

    ORB orb = ORB.init(myApplet, null);
 

An application or applet can be initialized in one or more ORBs. ORB initialization is a bootstrap call into the CORBA world.

Since:

JDK1.2

Method Summary

abstract void	connect(Object obj) Connects the given servant object (a Java object that is an instance of the server implementation class) to the ORB. The servant class must extend the ImplBase class corresponding to the interface that is supported by the server.
abstract TypeCode	create_alias_tc(String id, String name, TypeCode original_type) Creates a TypeCode object representing an IDL alias (typedef).
abstract Any	create_any() Creates an IDL Any object initialized to contain a Typecode object whose kind field is set to TCKind.tc_null.
abstract TypeCode	create_array_tc(int length, TypeCode element_type) Creates a TypeCode object representing an IDL array.
DynAny	create_basic_dyn_any(TypeCode type)
TypeCode	create_box_value_tc(String id, String name, TypeCode original_type)
abstract ContextList	create_context_list() Creates an empty ContextList object.
DynAny	create_dyn_any(Any value)
DynArray	create_dyn_array(TypeCode type)
DynEnum	create_dyn_enum(TypeCode type)
DynSequence	create_dyn_sequence(TypeCode type)
DynStruct	create_dyn_struct(TypeCode type)
DynUnion	create_dyn_union(TypeCode type)
abstract TypeCode	create_enum_tc(String id, String name, String[] members) Creates a TypeCode object representing an IDL enum.
abstract Environment	create_environment() Creates an Environment object.
abstract ExceptionList	create_exception_list() Creates an empty ExceptionList object.
abstract TypeCode	create_exception_tc(String id, String name, StructMember[] members) Creates a TypeCode object representing an IDL exception.
abstract TypeCode	create_interface_tc(String id, String name) Creates a TypeCode object representing an IDL interface.
abstract NVList	create_list(int count) Allocates an NVList with (probably) enough space for the specified number of NamedValue objects.
abstract NamedValue	create_named_value(String s, Any any, int flags) Creates a NamedValue object using the given name, value, and argument mode flags.
TypeCode	create_native_tc(String repository_id, String type_name) Create a TypeCode object for an IDL native type.
abstract NVList	create_operation_list(OperationDef oper) Creates an NVList initialized with argument descriptions for the operation described in the given OperationDef object.
abstract OutputStream	create_output_stream() Creates a new org.omg.
abstract TypeCode	create_recursive_sequence_tc(int bound, int offset) Creates a TypeCode object representing a a recursive IDL sequence.
abstract TypeCode	create_sequence_tc(int bound, TypeCode element_type) Creates a TypeCode object representing an IDL sequence.
abstract TypeCode	create_string_tc(int bound) Creates a TypeCode object representing an IDL string.
abstract TypeCode	create_struct_tc(String id, String name, StructMember[] members) Creates a TypeCode object representing an IDL struct.
abstract TypeCode	create_union_tc(String id, String name, TypeCode discriminator_type, UnionMember[] members) Creates a TypeCode object representing an IDL union.
TypeCode	create_value_tc(String repository_id, String name, boolean is_custom, String base_id, ValueMember[] members)
abstract TypeCode	create_wstring_tc(int bound) Creates a TypeCode object representing an IDL wstring (wide string).
abstract void	disconnect(Object obj) Disconnects the given servant object from the ORB. After this method returns, the ORB will reject incoming remote requests for the disconnected servant and will send the exception org.omg.
TypeCode	fill_in_recursive_value_tc(TypeCode tc, String id, ValueMember[] placeholder_replacement)
Current	get_current() Deprecated. use resolve_initial_references.
abstract Context	get_default_context() Gets the default Context object.
abstract Request	get_next_response() Gets the next Request instance for which a response has been received.
abstract TypeCode	get_primitive_tc(TCKind tcKind) Retrieves the TypeCode object that represents the given primitive IDL type.
boolean	get_service_information(short service_type, ServiceInformationHolder service_info)
static ORB	init() Returns the ORB singleton object.
static ORB	init(Applet app, Properties props) Creates a new ORB instance for an applet.
static ORB	init(String[] args, Properties props) Creates a new ORB instance for a standalone application.
abstract String[]	list_initial_services() Returns a list of the initially available CORBA object references, such as "NameService" and "InterfaceRepository".
org.omg.CORBA.StreamingPolicy	lookup_streaming_policy(String id)
Class	lookup_value_factory(String repository_id)
abstract String	object_to_string(Object obj) Converts the given CORBA object reference to a string.
void	perform_work() If called by the main thread, this operation performs an implementation-dependent unit of work.
abstract boolean	poll_next_response() Finds out if any of the deferred (asynchronous) invocations have a response yet.
org.omg.CORBA.StreamingPolicy	register_streaming_policy(String id, org.omg.CORBA.StreamingPolicy policy)
Class	register_value_factory(String repository_id, Class factory)
abstract Object	resolve_initial_references(String name) Resolves a specific object reference from the set of available initial service names.
void	run() This operation returns when the ORB has shutdown.
abstract void	send_multiple_requests_deferred(Request[] req) Sends multiple dynamic (DII) requests asynchronously.
abstract void	send_multiple_requests_oneway(Request[] req) Sends multiple dynamic (DII) requests asynchronously without expecting any responses.
protected abstract void	set_parameters(Applet app, Properties props) Allows the ORB implementation to be initialized with the given applet and parameters.
protected abstract void	set_parameters(String[] args, Properties props) Allows the ORB implementation to be initialized with the given parameters and properties.
void	shutdown(boolean wait_for_completion) This operation instructs the ORB to shut down, which causes all object adapters to shut down.
abstract Object	string_to_object(String str) Converts a string produced by the method object_to_string back to a CORBA object reference.
void	unregister_streaming_policy(String id)
void	unregister_value_factory(String repository_id)
boolean	work_pending() This operation returns true if the ORB needs the main thread to perform some work, and false if the ORB does not need the main thread.

Methods inherited from class java.lang.Object

clone , equals , finalize , getClass , hashCode , notify , notifyAll , toString , wait , wait , wait

Method Detail

init

public static ORB init()

Returns the ORB singleton object. This method always returns the same ORB instance, which is an instance of the class described by the org.omg.CORBA.ORBSingletonClass system property.

This no-argument version of the method init is used primarily as a factory for TypeCode objects, which are used by Helper classes to implement the method type. It is also used to create Any objects that are used to describe union labels (as part of creating a TypeCode object for a union).

This method is not intended to be used by applets, and in the event that it is called in an applet environment, the ORB it returns is restricted so that it can be used only as a factory for TypeCode objects. Any TypeCode objects it produces can be safely shared among untrusted applets.

If an ORB is created using this method from an applet, a system exception will be thrown if methods other than those for creating TypeCode objects are invoked.

Returns:

the singleton ORB

init

public static ORB init(String[] args,
                       Properties props)

Creates a new ORB instance for a standalone application. This method may be called from applications only and returns a new fully functional ORB object each time it is called.

Parameters:

args - command-line arguments for the application's main method; may be null

props - application-specific properties; may be null

Returns:

the newly-created ORB instance

init

public static ORB init(Applet app,
                       Properties props)

Creates a new ORB instance for an applet. This method may be called from applets only and returns a new fully-functional ORB object each time it is called.

Parameters:

app - the applet; may be null

props - applet-specific properties; may be null

Returns:

the newly-created ORB instance

set_parameters

protected abstract void set_parameters(String[] args,
                                       Properties props)

Allows the ORB implementation to be initialized with the given parameters and properties. This method, used in applications only, is implemented by subclass ORB implementations and called by the appropriate init method to pass in its parameters.

Parameters:

args - command-line arguments for the application's main method; may be null

props - application-specific properties; may be null

set_parameters

protected abstract void set_parameters(Applet app,
                                       Properties props)

Allows the ORB implementation to be initialized with the given applet and parameters. This method, used in applets only, is implemented by subclass ORB implementations and called by the appropriate init method to pass in its parameters.

Parameters:

app - the applet; may be null

props - applet-specific properties; may be null

connect

public abstract void connect(Object obj)

Connects the given servant object (a Java object that is an instance of the server implementation class) to the ORB. The servant class must extend the ImplBase class corresponding to the interface that is supported by the server. The servant must thus be a CORBA object reference, and inherit from org.omg.CORBA.Object. Servants created by the user can start receiving remote invocations after the method connect has been called. A servant may also be automatically and implicitly connected to the ORB if it is passed as an IDL parameter in an IDL method invocation on a non-local object, that is, if the servant object has to be marshalled and sent outside of the process address space.

Calling the method connect has no effect when the servant object is already connected to the ORB.

Parameters:

obj - the servant object reference

disconnect

public abstract void disconnect(Object obj)

Disconnects the given servant object from the ORB. After this method returns, the ORB will reject incoming remote requests for the disconnected servant and will send the exception org.omg.CORBA.OBJECT_NOT_EXIST back to the remote client. Thus the object appears to be destroyed from the point of view of remote clients. Note, however, that local requests issued using the servant directly do not pass through the ORB; hence, they will continue to be processed by the servant.

Calling the method disconnect has no effect if the servant is not connected to the ORB.

Parameters:

obj - The servant object to be disconnected from the ORB

list_initial_services

public abstract String[] list_initial_services()

Returns a list of the initially available CORBA object references, such as "NameService" and "InterfaceRepository".

Returns:

an array of String objects that represent the object references for CORBA services that are initially available with this ORB

resolve_initial_references

public abstract Object resolve_initial_references(String name)
                                           throws InvalidName

Resolves a specific object reference from the set of available initial service names.

Parameters:

name - the name of the initial service as a string

Returns:

the object reference associated with the given name

Throws:

InvalidName - if the given name is not associated with a known service

object_to_string

public abstract String object_to_string(Object obj)

Converts the given CORBA object reference to a string. Note that the format of this string is predefined by IIOP, allowing strings generated by a different ORB to be converted back into an object reference.

The resulting String object may be stored or communicated in any way that a String object can be manipulated.

Parameters:

obj - the object reference to stringify

Returns:

the string representing the object reference

string_to_object

public abstract Object string_to_object(String str)

Converts a string produced by the method object_to_string back to a CORBA object reference.

Parameters:

str - the string to be converted back to an object reference. It must be the result of converting an object reference to a string using the method object_to_string.

Returns:

the object reference

create_list

public abstract NVList create_list(int count)

Allocates an NVList with (probably) enough space for the specified number of NamedValue objects. Note that the specified size is only a hint to help with storage allocation and does not imply the maximum size of the list.

Parameters:

count - suggested number of NamedValue objects for which to allocate space

Returns:

the newly-created NVList

See Also:

NVList

create_operation_list

public abstract NVList create_operation_list(OperationDef oper)

Creates an NVList initialized with argument descriptions for the operation described in the given OperationDef object. This OperationDef object is obtained from an Interface Repository. The arguments in the returned NVList object are in the same order as in the original IDL operation definition, which makes it possible for the list to be used in dynamic invocation requests.

Parameters:

oper - the OperationDef object to use to create the list

Returns:

a newly-created NVList object containing descriptions of the arguments to the method described in the given OperationDef object

See Also:

NVList

create_named_value

public abstract NamedValue create_named_value(String s,
                                              Any any,
                                              int flags)

Creates a NamedValue object using the given name, value, and argument mode flags.

A NamedValue object serves as (1) a parameter or return value or (2) a context property. It may be used by itself or as an element in an NVList object.

Parameters:

s - the name of the NamedValue object

any - the Any value to be inserted into the NamedValue object

flags - the argument mode flags for the NamedValue: one of ARG_IN.value, ARG_OUT.value, or ARG_INOUT.value.

Returns:

the newly-created NamedValue object

See Also:

NamedValue

create_exception_list

public abstract ExceptionList create_exception_list()

Creates an empty ExceptionList object.

Returns:

the newly-created ExceptionList object

create_context_list

public abstract ContextList create_context_list()

Creates an empty ContextList object.

Returns:

the newly-created ContextList object

See Also:

ContextList, Context

get_default_context

public abstract Context get_default_context()

Gets the default Context object.

Returns:

the default Context object

See Also:

Context

create_environment

public abstract Environment create_environment()

Creates an Environment object.

Returns:

the newly-created Environment object

See Also:

Environment

create_output_stream

public abstract OutputStream create_output_stream()

Creates a new org.omg.CORBA.portable.OutputStream into which IDL method parameters can be marshalled during method invocation.

Returns:

the newly-created org.omg.CORBA.portable.OutputStream object

send_multiple_requests_oneway

public abstract void send_multiple_requests_oneway(Request[] req)

Sends multiple dynamic (DII) requests asynchronously without expecting any responses. Note that oneway invocations are not guaranteed to reach the server.

Parameters:

req - an array of request objects

send_multiple_requests_deferred

public abstract void send_multiple_requests_deferred(Request[] req)

Sends multiple dynamic (DII) requests asynchronously.

Parameters:

req - an array of Request objects

poll_next_response

public abstract boolean poll_next_response()

Finds out if any of the deferred (asynchronous) invocations have a response yet.

Returns:

true if there is a response available; false otherwise

get_next_response

public abstract Request get_next_response()
                                   throws WrongTransaction

Gets the next Request instance for which a response has been received.

Returns:

the next Request object ready with a response

Throws:

WrongTransaction - if the method get_next_response is called from a transaction scope different from the one from which the original request was sent. See the OMG Transaction Service specification for details.

get_primitive_tc

public abstract TypeCode get_primitive_tc(TCKind tcKind)

Retrieves the TypeCode object that represents the given primitive IDL type.

Parameters:

tcKind - the TCKind instance corresponding to the desired primitive type

Returns:

the requested TypeCode object

create_struct_tc

public abstract TypeCode create_struct_tc(String id,
                                          String name,
                                          StructMember[] members)

Creates a TypeCode object representing an IDL struct. The TypeCode object is initialized with the given id, name, and members.

Parameters:

id - the repository id for the struct

name - the name of the struct

members - an array describing the members of the struct

Returns:

a newly-created TypeCode object describing an IDL struct

create_union_tc

public abstract TypeCode create_union_tc(String id,
                                         String name,
                                         TypeCode discriminator_type,
                                         UnionMember[] members)

Creates a TypeCode object representing an IDL union. The TypeCode object is initialized with the given id, name, discriminator type, and members.

Parameters:

id - the repository id of the union

name - the name of the union

discriminator_type - the type of the union discriminator

members - an array describing the members of the union

Returns:

a newly-created TypeCode object describing an IDL union

create_enum_tc

public abstract TypeCode create_enum_tc(String id,
                                        String name,
                                        String[] members)

Creates a TypeCode object representing an IDL enum. The TypeCode object is initialized with the given id, name, and members.

Parameters:

id - the repository id for the enum

name - the name for the enum

members - an array describing the members of the enum

Returns:

a newly-created TypeCode object describing an IDL enum

create_alias_tc

public abstract TypeCode create_alias_tc(String id,
                                         String name,
                                         TypeCode original_type)

Creates a TypeCode object representing an IDL alias (typedef). The TypeCode object is initialized with the given id, name, and original type.

Parameters:

id - the repository id for the alias

name - the name for the alias

original_type - the TypeCode object describing the original type for which this is an alias

Returns:

a newly-created TypeCode object describing an IDL alias

create_exception_tc

public abstract TypeCode create_exception_tc(String id,
                                             String name,
                                             StructMember[] members)

Creates a TypeCode object representing an IDL exception. The TypeCode object is initialized with the given id, name, and members.

Parameters:

id - the repository id for the exception

name - the name for the exception

members - an array describing the members of the exception

Returns:

a newly-created TypeCode object describing an IDL exception

create_interface_tc

public abstract TypeCode create_interface_tc(String id,
                                             String name)

Creates a TypeCode object representing an IDL interface. The TypeCode object is initialized with the given id and name.

Parameters:

id - the repository id for the interface

name - the name for the interface

Returns:

a newly-created TypeCode object describing an IDL interface

create_string_tc

public abstract TypeCode create_string_tc(int bound)

Creates a TypeCode object representing an IDL string. The TypeCode object is initialized with the given bound, which represents the maximum length of the string. Zero indicates that the string described by this type code is unbounded.

Parameters:

bound - the bound for the string

Returns:

a newly-created TypeCode object describing an IDL string

create_wstring_tc

public abstract TypeCode create_wstring_tc(int bound)

Creates a TypeCode object representing an IDL wstring (wide string). The TypeCode object is initialized with the given bound, which represents the maximum length of the wide string. Zero indicates that the wide string described by this type code is unbounded.

Parameters:

bound - the bound for the wstring

Returns:

a newly-created TypeCode object describing an IDL wstring

create_sequence_tc

public abstract TypeCode create_sequence_tc(int bound,
                                            TypeCode element_type)

Creates a TypeCode object representing an IDL sequence. The TypeCode object is initialized with the given bound and element type.

Parameters:

bound - the bound for the sequence

element_type - the TypeCode object describing the elements contained in the sequence

Returns:

a newly-created TypeCode object describing an IDL sequence

create_recursive_sequence_tc

public abstract TypeCode create_recursive_sequence_tc(int bound,
                                                      int offset)

Creates a TypeCode object representing a a recursive IDL sequence.

For the IDL struct Foo in following code fragment, the offset parameter for creating its sequence would be 1:

    Struct Foo {
        long value;
        Sequence  Chain;
    };
 

Parameters:

bound - the bound for the sequence

offset - the index to the enclosing TypeCode object that describes the elements of this sequence

Returns:

a newly-created TypeCode object describing a recursive sequence

create_array_tc

public abstract TypeCode create_array_tc(int length,
                                         TypeCode element_type)

Creates a TypeCode object representing an IDL array. The TypeCode object is initialized with the given length and element type.

Parameters:

length - the length of the array

element_type - a TypeCode object describing the type of element contained in the array

Returns:

a newly-created TypeCode object describing an IDL array

create_native_tc

public TypeCode create_native_tc(String repository_id,
                                 String type_name)

Create a TypeCode object for an IDL native type.

Parameters:

id - the logical id for the native type.

name - the name of the native type.

Returns:

the requested TypeCode.

create_value_tc

public TypeCode create_value_tc(String repository_id,
                                String name,
                                boolean is_custom,
                                String base_id,
                                ValueMember[] members)

fill_in_recursive_value_tc

public TypeCode fill_in_recursive_value_tc(TypeCode tc,
                                           String id,
                                           ValueMember[] placeholder_replacement)

create_box_value_tc

public TypeCode create_box_value_tc(String id,
                                    String name,
                                    TypeCode original_type)

create_any

public abstract Any create_any()

Creates an IDL Any object initialized to contain a Typecode object whose kind field is set to TCKind.tc_null.

Returns:

a newly-created Any object

get_current

public Current get_current()

Deprecated. use resolve_initial_references.

Retrieves a Current object. The Current interface is used to manage thread-specific information for use by services such as transactions and security.

Returns:

a newly-created Current object

run

public void run()

This operation returns when the ORB has shutdown. If called by the main thread, it enables the ORB to perform work using the main thread. Otherwise it simply waits till the ORB has shutdown.

shutdown

public void shutdown(boolean wait_for_completion)

This operation instructs the ORB to shut down, which causes all object adapters to shut down. If the wait_for_completion parameter is true, this operation blocks until all ORB processing (including processing of currently executing requests, object deactivation, and other object adapter operations) has completed. The ORB.run() method will return after shutdown has been called.

work_pending

public boolean work_pending()

This operation returns true if the ORB needs the main thread to perform some work, and false if the ORB does not need the main thread.

perform_work

public void perform_work()

If called by the main thread, this operation performs an implementation-dependent unit of work. Otherwise it does nothing. The work_pending() and perform_work() operations can be used in conjunction to implement a simple polling loop that multiplexes the main thread among the ORB and other activities.

get_service_information

public boolean get_service_information(short service_type,
                                       ServiceInformationHolder service_info)

register_value_factory

public Class register_value_factory(String repository_id,
                                    Class factory)

unregister_value_factory

public void unregister_value_factory(String repository_id)

lookup_value_factory

public Class lookup_value_factory(String repository_id)

register_streaming_policy

public org.omg.CORBA.StreamingPolicy register_streaming_policy(String id,
                                                               org.omg.CORBA.StreamingPolicy policy)

unregister_streaming_policy

public void unregister_streaming_policy(String id)

lookup_streaming_policy

public org.omg.CORBA.StreamingPolicy lookup_streaming_policy(String id)

create_dyn_any

public DynAny create_dyn_any(Any value)

create_basic_dyn_any

public DynAny create_basic_dyn_any(TypeCode type)
                            throws org.omg.CORBA.DynAnyPackage.InconsistentTypeCode

create_dyn_struct

public DynStruct create_dyn_struct(TypeCode type)
                            throws org.omg.CORBA.DynAnyPackage.InconsistentTypeCode

create_dyn_sequence

public DynSequence create_dyn_sequence(TypeCode type)
                                throws org.omg.CORBA.DynAnyPackage.InconsistentTypeCode

create_dyn_array

public DynArray create_dyn_array(TypeCode type)
                          throws org.omg.CORBA.DynAnyPackage.InconsistentTypeCode

create_dyn_union

public DynUnion create_dyn_union(TypeCode type)
                          throws org.omg.CORBA.DynAnyPackage.InconsistentTypeCode

create_dyn_enum

public DynEnum create_dyn_enum(TypeCode type)
                        throws org.omg.CORBA.DynAnyPackage.InconsistentTypeCode