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.
*
* @author Ann Wollrath
* @version 1.27, 12/19/03
* @since 1.2
* @see java.rmi.activation.Activatable
*/
public final class ActivationDesc implements java.io.Serializable
{
/**
* @serial the group's identifier
*/
private ActivationGroupID groupID;
/**
* @serial the object's class name
*/
private String className;
/**
* @serial the object's code location
*/
private String location;
/**
* @serial the object's initialization data
*/
private MarshalledObject data;
/**
* @serial indicates whether the object should be restarted
*/
private boolean restart;
/** indicate compatibility with the Java 2 SDK v1.2 version of class */
private static final long serialVersionUID = 7455834104417690957L;
/**
* 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.
*
* @param className the object's fully package qualified class name
* @param location the object's code location (from where the class is
* loaded)
* @param data the object's initialization (activation) data contained
* in marshalled form.
* @exception ActivationException if the current group is nonexistent
* @since 1.2
*/
public ActivationDesc(String className,
String location,
MarshalledObject data)
throws ActivationException
{
this(ActivationGroup.internalCurrentGroupID(),
className, location, data, false);
}
/**
* 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.
*
* @param className the object's fully package qualified class name
* @param location the object's code location (from where the class is
* loaded)
* @param data the object's initialization (activation) data contained
* in marshalled form.
* @param 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.
* @exception ActivationException if the current group is nonexistent
* @since 1.2
*/
public ActivationDesc(String className,
String location,
MarshalledObject data,
boolean restart)
throws ActivationException
{
this(ActivationGroup.internalCurrentGroupID(),
className, location, data, 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.
*
*
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.
*
* @param groupID the group's identifier (obtained from registering
* ActivationSystem.registerGroup method). The group
* indicates the VM in which the object should be activated.
* @param className the object's fully package-qualified class name
* @param location the object's code location (from where the class is
* loaded)
* @param data the object's initialization (activation) data contained
* in marshalled form.
* @exception IllegalArgumentException if groupID is null
* @since 1.2
*/
public ActivationDesc(ActivationGroupID groupID,
String className,
String location,
MarshalledObject data)
{
this(groupID, className, location, data, false);
}
/**
* 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.
*
* @param groupID the group's identifier (obtained from registering
* ActivationSystem.registerGroup method). The group
* indicates the VM in which the object should be activated.
* @param className the object's fully package-qualified class name
* @param location the object's code location (from where the class is
* loaded)
* @param data the object's initialization (activation) data contained
* in marshalled form.
* @param 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.
* @exception IllegalArgumentException if groupID is null
* @since 1.2
*/
public ActivationDesc(ActivationGroupID groupID,
String className,
String location,
MarshalledObject data,
boolean restart)
{
if (groupID == null)
throw new IllegalArgumentException("groupID can't be null");
this.groupID = groupID;
this.className = className;
this.location = location;
this.data = data;
this.restart = restart;
}
/**
* 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.
*
* @return the group identifier
* @since 1.2
*/
public ActivationGroupID getGroupID() {
return groupID;
}
/**
* Returns the class name for the object specified by this
* descriptor.
* @return the class name
* @since 1.2
*/
public String getClassName() {
return className;
}
/**
* Returns the code location for the object specified by
* this descriptor.
* @return the code location
* @since 1.2
*/
public String getLocation() {
return location;
}
/**
* Returns a "marshalled object" containing intialization/activation
* data for the object specified by this descriptor.
* @return the object specific "initialization" data
* @since 1.2
*/
public MarshalledObject getData() {
return data;
}
/**
* Returns the "restart" mode of the object associated with
* this activation descriptor.
*
* @return 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
*/
public boolean getRestartMode() {
return restart;
}
/**
* Compares two activation descriptors for content equality.
*
* @param obj the Object to compare with
* @return true if these Objects are equal; false otherwise.
* @see java.util.Hashtable
* @since 1.2
*/
public boolean equals(Object obj) {
if (obj instanceof ActivationDesc) {
ActivationDesc desc = (ActivationDesc) obj;
return
((groupID == null ? desc.groupID == null :
groupID.equals(desc.groupID)) &&
(className == null ? desc.className == null :
className.equals(desc.className)) &&
(location == null ? desc.location == null:
location.equals(desc.location)) &&
(data == null ? desc.data == null :
data.equals(desc.data)) &&
(restart == desc.restart));
} else {
return false;
}
}
/**
* Return the same hashCode for similar ActivationDescs.
* @return an integer
* @see java.util.Hashtable
*/
public int hashCode()
{
return ((location == null
? 0
: location.hashCode() << 24) ^
(groupID == null
? 0
: groupID.hashCode() << 16) ^
(className == null
? 0
: className.hashCode() << 9) ^
(data == null
? 0
: data.hashCode() << 1) ^
(restart
? 1
: 0));
}
}