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org.vrspace.server
Class VRObject  

java.lang.Object
  java.util.Observable
      org.vrspace.server.VRObject

All Implemented Interfaces:

java.lang.Cloneable

Direct Known Subclasses:

DBObject, PassiveVRObject, PrivateVRObject, PublicVRObject

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public class VRObject

extends java.util.Observable

implements java.lang.Cloneable

Generic VRObject class.
Defines event forwarding, does not check nor set actual field value.
Subclasses should override setValue() method to implement different behavior, i.e. store object to database and/or forward events.

NOTES:
- set_* (see setField()) method may access both Client and Dispatcher via Request
- before invoking set_*, request may forwarded to all the Observers, depending on sendEvent()/setValue() implementation
- along with request, other Clients (Observers) get reference to originating Client - TAKE CARE of public variables !!!
- this way, clients may send requests (Client.update()) to each other without Dispatcher interference - usefull for chat, smart server-side classes etc.
- it's up to each client to check the request origin and perform other actions
- if set_ method is invoked before forwarding, it may cancel forwarding by calling clearChanged(), depending on sendEvent()/setValue() implementation
- in general, sendEvent() should invoke setChanged() or generate VRObjectException, setValue() should invoke notifyObservers( Request ), and somewhere between those field is set and clearChanged() is eventualy called

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Field Summary
long	db_id
private static long	instances
(package private)  boolean	isNew
private  java.lang.Object	lock
private static java.util.Hashtable	lockedClasses
private  java.lang.String	myClassName
private  int	pos
static java.util.HashMap	primitiveMap
static java.util.HashMap	primitives
private  Request	request

 

Fields inherited from class java.util.Observable

 

Constructor Summary

VRObject()

 

Method Summary
static java.lang.String	arrayToString(java.lang.Object array)           Converts array val to String.
boolean	canRead(java.lang.String name)           Returns true if there's either field or get_ method
boolean	canWrite(java.lang.String name)           Returns true if there's either field or set_ method
java.lang.Object	clone()           This method may be called to create a new copy of the Object.
boolean	equals(VRObject obj)           VRObject.equals( VRObject ) if class and db_id are the same
(package private)  java.lang.String	fieldToText(java.lang.reflect.Field field)
int	fromString(java.lang.String s)           Uses toString() formated String to set variables
static VRObject[]	fromText(java.lang.String definition)           Returns array of objects defined by string in toText() format
java.lang.String	getClassName()           Returns class name without package name.
java.lang.Object	getField(java.lang.String name)           Returns a field value.
java.lang.String[]	getFields()           Returns names of all public member varaibles.
long	getId()           Returns objects unique id
org.vrspace.util.ID	getID()           Returns objects unique id
VRObject[]	getMemebers()           Returns VRObjects that are member variables of this object.
boolean	hasField(java.lang.String name)           Returns true if this object contains public field with this name
boolean	hasMethod(java.lang.String name)           Returns true if this object contains public method with this name
boolean	isNew()           new object?
(package private)  boolean	lock(VRObject o)           Lock the object, o is new owner.
(package private)  boolean	lockClass(VRObject o)           Lock the class, o is new owner.
static VRObject	newInstance(java.lang.String className)           Creates new instance of className
private  java.lang.String	nextToken(java.util.StringTokenizer st)
void	sendEvent(Request r)           Forwards request r to other clients, Observers added by Dispatcher.
boolean	sendResponse()           send OK on successfull execution?
void	setField(Request r)           Sets field r.getEventName() to r.getEventValue()
void	setField(java.lang.String name, java.lang.String value)           Sets field name to value
void	setField(java.lang.String name, java.lang.String value, Request r)           Equals to obj.name = value.
void	setFields(java.lang.String[] names, java.lang.String args)           setFields() on all variables specified in parse args and set each
void	setFields(VRObject o)           Takes field values from passed object, by field name.
protected  void	setValue(Request r)           This implementation does nothing
static java.lang.Object	stringToArray(java.lang.Class cl, java.lang.String val)           Converts String in arrayToString() format back to array.
java.lang.String	toString()           Converts VRObject to String.
java.lang.String	toText()           Returns string representation of objects, used by fromText()
static java.lang.String	toText(java.lang.Object[] obj)           Returns string representation of objects, used by fromText()
java.lang.String	toText(java.lang.String filter)           As toText(), but does not return fields beginning with filter.
(package private)  boolean	unlock(VRObject o)           unlock
(package private)  boolean	unlockClass(VRObject o)           unlock

 

Methods inherited from class java.util.Observable

addObserver, clearChanged, countObservers, deleteObserver, deleteObservers, hasChanged, notifyObservers, notifyObservers, setChanged

 

Methods inherited from class java.lang.Object

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

 

Field Detail

db_id

public long db_id

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pos

private int pos

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request

private Request request

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myClassName

private java.lang.String myClassName

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lock

private java.lang.Object lock

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lockedClasses

private static java.util.Hashtable lockedClasses

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isNew

boolean isNew

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instances

private static long instances

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primitives

public static final java.util.HashMap primitives

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primitiveMap

public static final java.util.HashMap primitiveMap

Constructor Detail

VRObject

public VRObject()

Method Detail

isNew

public boolean isNew()

new object?

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sendResponse

public boolean sendResponse()

send OK on successfull execution?

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getId

public long getId()

Returns objects unique id

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getID

public org.vrspace.util.ID getID()

Returns objects unique id

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fromString

public int fromString(java.lang.String s)
               throws VRObjectException,
                      java.lang.NoSuchFieldException,
                      java.lang.ClassNotFoundException,
                      java.lang.IllegalAccessException,
                      java.lang.InstantiationException,
                      java.lang.NoSuchMethodException,
                      java.lang.reflect.InvocationTargetException

Uses toString() formated String to set variables

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nextToken

private java.lang.String nextToken(java.util.StringTokenizer st)

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toString

public java.lang.String toString()

Converts VRObject to String. BUG: quotes inside string

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arrayToString

public static java.lang.String arrayToString(java.lang.Object array)

Converts array val to String.

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stringToArray

public static java.lang.Object stringToArray(java.lang.Class cl,
                                             java.lang.String val)

Converts String in arrayToString() format back to array.

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toText

public static java.lang.String toText(java.lang.Object[] obj)
                               throws java.lang.IllegalAccessException

Returns string representation of objects, used by fromText()

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toText

public java.lang.String toText()
                        throws java.lang.IllegalAccessException

Returns string representation of objects, used by fromText()

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fieldToText

java.lang.String fieldToText(java.lang.reflect.Field field)
                       throws java.lang.IllegalAccessException

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toText

public java.lang.String toText(java.lang.String filter)
                        throws java.lang.IllegalAccessException

As toText(), but does not return fields beginning with filter. Used for sending events over the network.

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getClassName

public java.lang.String getClassName()

Returns class name without package name.

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fromText

public static VRObject[] fromText(java.lang.String definition)
                           throws java.lang.NoSuchMethodException,
                                  java.lang.NoSuchFieldException,
                                  java.lang.IllegalAccessException,
                                  java.lang.InstantiationException,
                                  java.lang.ClassNotFoundException,
                                  java.lang.reflect.InvocationTargetException,
                                  VRObjectException

Returns array of objects defined by string in toText() format

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newInstance

public static VRObject newInstance(java.lang.String className)

Creates new instance of className

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setFields

public void setFields(java.lang.String[] names,
                      java.lang.String args)
               throws VRObjectException

setFields() on all variables specified in parse args and set each

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setFields

public void setFields(VRObject o)

Takes field values from passed object, by field name. Non-exisisting fields ignored.

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setField

public void setField(java.lang.String name,
                     java.lang.String value)
              throws VRObjectException

Sets field name to value

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setField

public void setField(Request r)
              throws VRObjectException

Sets field r.getEventName() to r.getEventValue()

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setField

public void setField(java.lang.String name,
                     java.lang.String value,
                     Request r)
              throws VRObjectException

Equals to obj.name = value. If this raises exception, tries obj.set_name( Request r, String value )

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sendEvent

public void sendEvent(Request r)
               throws RequestException

Forwards request r to other clients, Observers added by Dispatcher. Throws RequestException if request target is another object. Calls setValue() method which actualy forwards the event. NOTE: All the Observers (Clients!) have access to VRObject - TAKE CARE of public variables (reading) and public methodes (generating events)

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setValue

protected void setValue(Request r)

This implementation does nothing

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getMemebers

public VRObject[] getMemebers()

Returns VRObjects that are member variables of this object.

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getFields

public java.lang.String[] getFields()

Returns names of all public member varaibles. Use getField( String ) to retreive value.

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hasField

public boolean hasField(java.lang.String name)

Returns true if this object contains public field with this name

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hasMethod

public boolean hasMethod(java.lang.String name)

Returns true if this object contains public method with this name

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canWrite

public boolean canWrite(java.lang.String name)

Returns true if there's either field or set_ method

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canRead

public boolean canRead(java.lang.String name)

Returns true if there's either field or get_ method

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getField

public java.lang.Object getField(java.lang.String name)
                          throws VRObjectException

Returns a field value. If there's no member with this name, tries to execute "get_"+name method.

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equals

public boolean equals(VRObject obj)

VRObject.equals( VRObject ) if class and db_id are the same

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lock

boolean lock(VRObject o)

Lock the object, o is new owner. Usage: transactions. This should be package protected.

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unlock

boolean unlock(VRObject o)

unlock

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lockClass

boolean lockClass(VRObject o)

Lock the class, o is new owner. Usage: transactions. This should be package protected.

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unlockClass

boolean unlockClass(VRObject o)

unlock

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clone

public java.lang.Object clone()

Description copied from class: java.lang.Object

This method may be called to create a new copy of the Object. The typical behavior is as follows:

• o == o.clone() is false
• o.getClass() == o.clone().getClass() is true
• o.equals(o) is true

However, these are not strict requirements, and may be violated if necessary. Of the three requirements, the last is the most commonly violated, particularly if the subclass does not override Object.equals(Object)>Object.equals(Object) 55 .

If the Object you call clone() on does not implement java.lang.Cloneable (which is a placeholder interface), then a CloneNotSupportedException is thrown. Notice that Object does not implement Cloneable; this method exists as a convenience for subclasses that do.

Object's implementation of clone allocates space for the new Object using the correct class, without calling any constructors, and then fills in all of the new field values with the old field values. Thus, it is a shallow copy. However, subclasses are permitted to make a deep copy.

All array types implement Cloneable, and override this method as follows (it should never fail):

 public Object clone()
 {
   try
     {
       super.clone();
     }
   catch (CloneNotSupportedException e)
     {
       throw new InternalError(e.getMessage());
     }
 }
 

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Overview  Package   Class  Use  Deprecated  Index
Home >> All >> org >> vrspace >> [ server overview ]	PREV CLASS  NEXT CLASS
SUMMARY:  JAVADOC |  SOURCE |  DOWNLOAD | NESTED | FIELD | CONSTR | METHOD	DETAIL: FIELD | CONSTR | METHOD

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