com.sun.corba.se.spi.extension

Class ServantCachingPolicy

java.lang.Object

org.omg.CORBA.LocalObject

com.sun.corba.se.spi.extension.ServantCachingPolicy

All Implemented Interfaces:

Serializable, Object, Policy, PolicyOperations, IDLEntity

public class ServantCachingPolicy
extends LocalObject
implements Policy

Policy used to implement servant caching optimization in the POA. Creating a POA with an instance pol of this policy where pol.getType() > NO_SERVANT_CACHING will cause the servant to be looked up in the POA and cached in the LocalClientRequestDispatcher when the ClientRequestDispatcher is colocated with the implementation of the objref. This greatly speeds up invocations at the cost of violating the POA semantics. In particular, every request to a particular objref must be handled by the same servant. Note that this is typically the case for EJB implementations.

If servant caching is used, there are two different additional features of the POA that are expensive:

1. POA current semantics
2. Proper handling of POA destroy.
   POA current semantics requires maintaining a ThreadLocal stack of invocation information that is always available for POACurrent operations. Maintaining this stack is expensive on the timescale of optimized co-located calls, so the option is provided to turn it off. Similarly, causing POA.destroy() calls to wait for all active calls in the POA to complete requires careful tracking of the entry and exit of invocations in the POA. Again, tracking this is somewhat expensive.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static int	FULL_SEMANTICS Perform servant caching, preserving POA current and POA destroy semantics.
static int	INFO_ONLY_SEMANTICS Perform servant caching, preservent only POA current semantics.
static int	MINIMAL_SEMANTICS Perform servant caching, not preserving POA current or POA destroy semantics.
static int	NO_SERVANT_CACHING Do not cache servants in the ClientRequestDispatcher.

Method Summary

Modifier and Type	Method and Description
Policy	copy() Returns a copy of the Policy object.
void	destroy() Destroys the Policy object.
static ServantCachingPolicy	getFullPolicy()
static ServantCachingPolicy	getInfoOnlyPolicy()
static ServantCachingPolicy	getMinimalPolicy()
static ServantCachingPolicy	getPolicy() Return the default servant caching policy.
int	getType()
int	policy_type() Returns the constant value that corresponds to the type of the policy object.
String	toString()
String	typeToName()

Methods inherited from class org.omg.CORBA.LocalObject

_create_request, _create_request, _duplicate, _get_domain_managers, _get_interface_def, _get_interface, _get_policy, _hash, _invoke, _is_a, _is_equivalent, _is_local, _non_existent, _orb, _release, _releaseReply, _request, _request, _servant_postinvoke, _servant_preinvoke, _set_policy_override, validate_connection

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.omg.CORBA.Object

_create_request, _create_request, _duplicate, _get_domain_managers, _get_interface_def, _get_policy, _hash, _is_a, _is_equivalent, _non_existent, _release, _request, _set_policy_override

Field Detail

NO_SERVANT_CACHING

public static final int NO_SERVANT_CACHING

Do not cache servants in the ClientRequestDispatcher. This will always support the full POA semantics, including changing the servant that handles requests on a particular objref.

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Constant Field Values

FULL_SEMANTICS

public static final int FULL_SEMANTICS

Perform servant caching, preserving POA current and POA destroy semantics. We will use this as the new default, as the app server is making heavier use now of POA facilities.

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Constant Field Values

INFO_ONLY_SEMANTICS

public static final int INFO_ONLY_SEMANTICS

Perform servant caching, preservent only POA current semantics. At least this level is required in order to support selection of ObjectCopiers for co-located RMI-IIOP calls, as the current copier is stored in OAInvocationInfo, which must be present on the stack inside the call.

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Constant Field Values

MINIMAL_SEMANTICS

public static final int MINIMAL_SEMANTICS

Perform servant caching, not preserving POA current or POA destroy semantics.

See Also:

Constant Field Values

Method Detail

typeToName

public String typeToName()

toString

public String toString()

Overrides:

toString in class Object

getType

public int getType()

getPolicy

public static ServantCachingPolicy getPolicy()

Return the default servant caching policy.

getFullPolicy

public static ServantCachingPolicy getFullPolicy()

getInfoOnlyPolicy

public static ServantCachingPolicy getInfoOnlyPolicy()

getMinimalPolicy

public static ServantCachingPolicy getMinimalPolicy()

policy_type

public int policy_type()

Description copied from interface: PolicyOperations

Returns the constant value that corresponds to the type of the policy object. The values of the policy objects are allocated by the OMG. New values for PolicyType should be obtained from the OMG by sending mail to request@omg.org. In general the constant values that are allocated are defined in conjunction with the definition of the corresponding policy object.

Specified by:

policy_type in interface PolicyOperations

Returns:

the constant value that corresponds to the type of the policy object

copy

public Policy copy()

Description copied from interface: PolicyOperations

Returns a copy of the Policy object. The copy does not retain any relationships that the policy had with any domain or object.

Specified by:

copy in interface PolicyOperations

Returns:

a copy of the Policy object

destroy

public void destroy()

Description copied from interface: PolicyOperations

Destroys the Policy object. It is the responsibility of the Policy object to determine whether it can be destroyed.

Specified by:

destroy in interface PolicyOperations