org.coweb.oe
Class Operation

java.lang.Object
  org.coweb.oe.Operation

Direct Known Subclasses:

DeleteOperation, InsertOperation, UpdateOperation

public abstract class Operation
extends Object

Field Summary

protected ContextVector	contextVector
protected boolean	immutable
protected static int	infinity
protected String	key
protected boolean	local
protected int	order
protected int	position
protected int	seqId
protected int	siteId
protected String	type
protected String	value
protected Vector<Operation>	xCache

Constructor Summary

protected

Operation(Map<String,Object> args) Contains information about a local or remote event for transformation.

Method Summary

void	addToCache(int siteCount) Caches a transformed copy of this original operation for faster future transformations.
int	compareByContext(Operation op) Computes an ordered comparison of this op and another based on their context vectors.
int	compareByOrder(Operation op) Computes an ordered comparison of this op and another based on their position in the total op order.
Operation	copy() Makes a copy of this operation object.
static String	createHistoryKey(int site, int seq)
static Operation	createOperationFromState(Object[] state)
static Operation	createOperationFromType(String type, Map<String,Object> args)
ContextVector	getContextVector()
Operation	getFromCache(ContextVector cv) Gets a version of the given operation previously transformed into the given context if available.
int	getPosition()
int	getSeqId()
int	getSiteId()
Object[]	getState() Serializes the operation as an array of values for transmission.
String	getValue()
void	setImmutable(boolean immutable)
void	setState(Object[] arr) Unserializes operation data and sets it as the instance data.
String	toString()
Operation	transformWith(Operation op) Transforms this operation to include the effects of the operation provided as a parameter IT(this, op).
abstract Operation	transformWithDelete(Operation op)
abstract Operation	transformWithInsert(Operation op)
abstract Operation	transformWithUpdate(Operation op)
void	upgradeContextTo(Operation op) Upgrades the context of this operation to reflect the inclusion of a single other operation from some site.

Methods inherited from class java.lang.Object

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

Field Detail

infinity

protected static final int infinity

See Also:

Constant Field Values

siteId

protected int siteId

seqId

protected int seqId

type

protected String type

local

protected boolean local

contextVector

protected ContextVector contextVector

key

protected String key

value

protected String value

position

protected int position

order

protected int order

immutable

protected boolean immutable

xCache

protected Vector<Operation> xCache

Constructor Detail

Operation

protected Operation(Map<String,Object> args)
             throws OperationEngineException

Contains information about a local or remote event for transformation. Initializes the operation from serialized state or individual props if state is not defined in the args parameter.

Parameters:

{Object[]} - args.state Array in format returned by getState bundling the following individual parameter values

{Number} - args.siteId Integer site ID where the op originated

{ContextVector} - args.contextVector Context in which the op occurred

{String} - args.key Name of the property the op affected

{String} - args.value Value of the op

{Number} - args.position Integer position of the op in a linear collection

{Number} - args.order Integer sequence number of the op in the total op order across all sites

{Number} - args.seqId Integer sequence number of the op at its originating site. If undefined, computed from the context vector and site ID.

{Boolean} - args.immutable True if the op cannot be changed, most likely because it is in a history buffer somewhere to this instance

Throws:

OperationEngineException

Method Detail

createOperationFromType

public static Operation createOperationFromType(String type,
                                                Map<String,Object> args)
                                         throws OperationEngineException

Throws:

OperationEngineException

createOperationFromState

public static Operation createOperationFromState(Object[] state)
                                          throws OperationEngineException

Throws:

OperationEngineException

createHistoryKey

public static String createHistoryKey(int site,
                                      int seq)

toString

public String toString()

Overrides:

toString in class Object

transformWithDelete

public abstract Operation transformWithDelete(Operation op)

transformWithInsert

public abstract Operation transformWithInsert(Operation op)

transformWithUpdate

public abstract Operation transformWithUpdate(Operation op)

getState

public Object[] getState()

Serializes the operation as an array of values for transmission.

Returns:

{Object[]} Array with the name of the operation type and all of its instance variables as primitive JS types

setState

public void setState(Object[] arr)
              throws OperationEngineException

Unserializes operation data and sets it as the instance data. Throws an exception if the state is not from an operation of the same type.

Parameters:

{Object[]} - arr Array in the format returned by getState

Throws:

OperationEngineException

copy

public Operation copy()
               throws OperationEngineException

Makes a copy of this operation object. Takes a shortcut and returns a ref to this instance if the op is marked as mutable.

Throws:

OperationEngineException

getFromCache

public Operation getFromCache(ContextVector cv)
                       throws OperationEngineException

Gets a version of the given operation previously transformed into the given context if available.

Parameters:

{ContextVector} - cv Context of the transformed op to seek

Throws:

OperationEngineException

addToCache

public void addToCache(int siteCount)
                throws OperationEngineException

Caches a transformed copy of this original operation for faster future transformations.

Parameters:

{Number} - Integer count of active sites, including the local one

Throws:

OperationEngineException

compareByContext

public int compareByContext(Operation op)

Computes an ordered comparison of this op and another based on their context vectors. Used for sorting operations by their contexts.

Parameters:

{Operation} - op Other operation

compareByOrder

public int compareByOrder(Operation op)

Computes an ordered comparison of this op and another based on their position in the total op order.

Parameters:

{Operation} - op Other operation

transformWith

public Operation transformWith(Operation op)
                        throws OperationEngineException

Transforms this operation to include the effects of the operation provided as a parameter IT(this, op). Upgrade the context of this op to reflect the inclusion of the other.

Throws:

OperationEngineException

{Error} - If this op to be transformed is immutable or if the this operation subclass does not implement the transform method needed to handle the passed op

upgradeContextTo

public void upgradeContextTo(Operation op)
                      throws OperationEngineException

Upgrades the context of this operation to reflect the inclusion of a single other operation from some site.

Parameters:

{Operation} - The operation to include in the context of this op

Throws:

OperationEngineException

{Error} - If this op to be upgraded is immutable

getSiteId

public int getSiteId()

getSeqId

public int getSeqId()

getValue

public String getValue()

getPosition

public int getPosition()

getContextVector

public ContextVector getContextVector()

setImmutable

public void setImmutable(boolean immutable)