java.rmi.activation

Class ActivationDesc

java.lang.Object

java.rmi.activation.ActivationDesc

All Implemented Interfaces:

Serializable

public final class ActivationDesc
extends Object
implements Serializable

An activation descriptor contains the information necessary to activate an object:

• the object's group identifier,
• the object's fully-qualified class name,
• the object's code location (the location of the class), a codebase URL path,
• the object's restart "mode", and,
• a "marshalled" object that can contain object specific initialization data.

A descriptor registered with the activation system can be used to recreate/activate the object specified by the descriptor. The MarshalledObject in the object's descriptor is passed as the second argument to the remote object's constructor for object to use during reinitialization/activation.

Since:

1.2

See Also:

Activatable, Serialized Form

Constructor Summary

Constructors

Constructor and Description
ActivationDesc(ActivationGroupID groupID, String className, String location, MarshalledObject<?> data) Constructs an object descriptor for an object whose class name is className that can be loaded from the code location and whose initialization information is data.
ActivationDesc(ActivationGroupID groupID, String className, String location, MarshalledObject<?> data, boolean restart) Constructs an object descriptor for an object whose class name is className that can be loaded from the code location and whose initialization information is data.
ActivationDesc(String className, String location, MarshalledObject<?> data) Constructs an object descriptor for an object whose class name is className, that can be loaded from the code location and whose initialization information is data.
ActivationDesc(String className, String location, MarshalledObject<?> data, boolean restart) Constructs an object descriptor for an object whose class name is className, that can be loaded from the code location and whose initialization information is data.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	equals(Object obj) Compares two activation descriptors for content equality.
String	getClassName() Returns the class name for the object specified by this descriptor.
MarshalledObject<?>	getData() Returns a "marshalled object" containing intialization/activation data for the object specified by this descriptor.
ActivationGroupID	getGroupID() Returns the group identifier for the object specified by this descriptor.
String	getLocation() Returns the code location for the object specified by this descriptor.
boolean	getRestartMode() Returns the "restart" mode of the object associated with this activation descriptor.
int	hashCode() Return the same hashCode for similar ActivationDescs.

Methods inherited from class java.lang.Object

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

Constructor Detail

ActivationDesc

public ActivationDesc(String className,
              String location,
              MarshalledObject<?> data)
               throws ActivationException

Constructs an object descriptor for an object whose class name is className, that can be loaded from the code location and whose initialization information is data. If this form of the constructor is used, the groupID defaults to the current id for ActivationGroup for this VM. All objects with the same ActivationGroupID are activated in the same VM.

Note that objects specified by a descriptor created with this constructor will only be activated on demand (by default, the restart mode is false). If an activatable object requires restart services, use one of the ActivationDesc constructors that takes a boolean parameter, restart.

This constructor will throw ActivationException if there is no current activation group for this VM. To create an ActivationGroup use the ActivationGroup.createGroup method.

Parameters:

className - the object's fully package qualified class name

location - the object's code location (from where the class is loaded)

data - the object's initialization (activation) data contained in marshalled form.

Throws:

ActivationException - if the current group is nonexistent

Since:

1.2

ActivationDesc

public ActivationDesc(String className,
              String location,
              MarshalledObject<?> data,
              boolean restart)
               throws ActivationException

Constructs an object descriptor for an object whose class name is className, that can be loaded from the code location and whose initialization information is data. If this form of the constructor is used, the groupID defaults to the current id for ActivationGroup for this VM. All objects with the same ActivationGroupID are activated in the same VM.

This constructor will throw ActivationException if there is no current activation group for this VM. To create an ActivationGroup use the ActivationGroup.createGroup method.

Parameters:

className - the object's fully package qualified class name

location - the object's code location (from where the class is loaded)

data - the object's initialization (activation) data contained in marshalled form.

restart - if true, the object is restarted (reactivated) when either the activator is restarted or the object's activation group is restarted after an unexpected crash; if false, the object is only activated on demand. Specifying restart to be true does not force an initial immediate activation of a newly registered object; initial activation is lazy.

Throws:

ActivationException - if the current group is nonexistent

Since:

1.2

ActivationDesc

public ActivationDesc(ActivationGroupID groupID,
              String className,
              String location,
              MarshalledObject<?> data)

Constructs an object descriptor for an object whose class name is className that can be loaded from the code location and whose initialization information is data. All objects with the same groupID are activated in the same Java VM.

Note that objects specified by a descriptor created with this constructor will only be activated on demand (by default, the restart mode is false). If an activatable object requires restart services, use one of the ActivationDesc constructors that takes a boolean parameter, restart.

Parameters:

groupID - the group's identifier (obtained from registering ActivationSystem.registerGroup method). The group indicates the VM in which the object should be activated.

className - the object's fully package-qualified class name

location - the object's code location (from where the class is loaded)

data - the object's initialization (activation) data contained in marshalled form.

Throws:

IllegalArgumentException - if groupID is null

Since:

1.2

ActivationDesc

public ActivationDesc(ActivationGroupID groupID,
              String className,
              String location,
              MarshalledObject<?> data,
              boolean restart)

Constructs an object descriptor for an object whose class name is className that can be loaded from the code location and whose initialization information is data. All objects with the same groupID are activated in the same Java VM.

Parameters:

groupID - the group's identifier (obtained from registering ActivationSystem.registerGroup method). The group indicates the VM in which the object should be activated.

className - the object's fully package-qualified class name

location - the object's code location (from where the class is loaded)

data - the object's initialization (activation) data contained in marshalled form.

restart - if true, the object is restarted (reactivated) when either the activator is restarted or the object's activation group is restarted after an unexpected crash; if false, the object is only activated on demand. Specifying restart to be true does not force an initial immediate activation of a newly registered object; initial activation is lazy.

Throws:

IllegalArgumentException - if groupID is null

Since:

1.2

Method Detail

getGroupID

public ActivationGroupID getGroupID()

Returns the group identifier for the object specified by this descriptor. A group provides a way to aggregate objects into a single Java virtual machine. RMI creates/activates objects with the same groupID in the same virtual machine.

Returns:

the group identifier

Since:

1.2

getClassName

public String getClassName()

Returns the class name for the object specified by this descriptor.

Returns:

the class name

Since:

1.2

getLocation

public String getLocation()

Returns the code location for the object specified by this descriptor.

Returns:

the code location

Since:

1.2

getData

public MarshalledObject<?> getData()

Returns a "marshalled object" containing intialization/activation data for the object specified by this descriptor.

Returns:

the object specific "initialization" data

Since:

1.2

getRestartMode

public boolean getRestartMode()

Returns the "restart" mode of the object associated with this activation descriptor.

Returns:

true if the activatable object associated with this activation descriptor is restarted via the activation daemon when either the daemon comes up or the object's group is restarted after an unexpected crash; otherwise it returns false, meaning that the object is only activated on demand via a method call. Note that if the restart mode is true, the activator does not force an initial immediate activation of a newly registered object; initial activation is lazy.

Since:

1.2

equals

public boolean equals(Object obj)

Compares two activation descriptors for content equality.

Overrides:

equals in class Object

Parameters:

obj - the Object to compare with

Returns:

true if these Objects are equal; false otherwise.

Since:

1.2

See Also:

Hashtable

hashCode

public int hashCode()

Return the same hashCode for similar ActivationDescs.

Overrides:

hashCode in class Object

Returns:

an integer

See Also:

Hashtable