PushTechnology.ClientInterface.Data.IDeltaType Interface Reference

The optional extension provided by IDataType implementations that support incremental changes to values. More...

Inheritance diagram for PushTechnology.ClientInterface.Data.IDeltaType:

Public Member Functions
void	WriteDelta (object delta, Stream outputStream)
	Serializes a delta to binary. More...
IBytes	ToBytes (object delta)
	Returns the serialized form of the given delta as IBytes. More...
object	ReadDelta (byte[] input, int offset, int length)
	Creates a delta from binary segment. More...
object	ReadDelta (byte[] input)
	Creates a delta from binary segment. More...
object	ReadDelta (IBytes input)
	Creates a delta from IBytes. More...
object	Diff (object oldValue, object newValue)
	Creates a delta from two values. More...
object	Apply (object oldValue, object delta)
	Applies a delta to a value. More...
bool	IsValueCheaper (object value, object delta)
	Calculates if value is cheaper than delta . The result is typically determined by the length of the serialized form but can also consider the complexity of the delta. More...

Properties
string	Name [get]
	Returns the external identifier for this delta type. More...
object	NoChange [get]
	Returns a constant that indicates no changes between values. More...

Detailed Description

The optional extension provided by IDataType implementations that support incremental changes to values.

Each implementation specifies a value type and a delta type. Two values, oldValue and newValue, can be compared to produce a delta using Diff(object,object). The delta can be separately applied to oldValue to create newValue using Apply(object,object).

Delta types should provide a string representation. Equality is optional for delta types.

Deferred parsing

Implementations can choose not to fully validate values when they are read, but instead defer parsing until it is required. Consequently, all methods that accept values can throw InvalidDataException.

Since 5.8

Member Function Documentation

object PushTechnology.ClientInterface.Data.IDeltaType.Apply	(	object	oldValue,
		object	delta
	)

Applies a delta to a value.

Parameters

oldValue	The old value object.
delta	The delta object to apply to the old value object.

Returns

The new value object. The old value object will be returned if the delta had no effect.

object PushTechnology.ClientInterface.Data.IDeltaType.Diff	(	object	oldValue,
		object	newValue
	)

Creates a delta from two values.

If there are many differences between oldValue and newValue, the result might require more bytes to transmit than the new value, or be computationally expensive to apply. In this case, it is better to discard oldValue and publish newValue in its place. This can be checked using IsValueCheaper(object,object).

The implementation can return the special constant NoChange to indicate the oldValue and newValue are equivalent and there is no change to publish.

Parameters

oldValue	The old value object.
newValue	The new value object.

Returns

The delta representing the difference between oldValue and newValue.

bool PushTechnology.ClientInterface.Data.IDeltaType.IsValueCheaper	(	object	value,
		object	delta
	)

Calculates if value is cheaper than delta . The result is typically determined by the length of the serialized form but can also consider the complexity of the delta.

Parameters

value	The value object.
delta	The delta object.

Returns

True if value is considered cheaper than delta . Otherwise false.

object PushTechnology.ClientInterface.Data.IDeltaType.ReadDelta	(	byte[]	input,
		int	offset,
		int	length
	)

Creates a delta from binary segment.

Parameters

input	The binary data. The implementation may re-use the array to avoid copying. The caller must ensure the array is not modified.
offset	The starting index of the segment.
length	The length of the segment.

Returns

The delta object.

Implemented in PushTechnology.ClientInterface.Data.IDeltaType< TValue, TDelta >.

object PushTechnology.ClientInterface.Data.IDeltaType.ReadDelta

(

byte[]

input

)

Creates a delta from binary segment.

This is equivalent to ReadDelta(input,0,input.Length).

Parameters

input

The binary data. The implementation may re-use the array to avoid copying. The caller must ensure the array is not modified.

Returns

The delta object.

Implemented in PushTechnology.ClientInterface.Data.IDeltaType< TValue, TDelta >.

object PushTechnology.ClientInterface.Data.IDeltaType.ReadDelta

(

IBytes

input

)

Creates a delta from IBytes.

This is equivalent to calling ReadDelta(byte[]) with the result of IBytes.ToByteArray as argument.

Since 6.0.

Parameters

input

The binary data.

Returns

The delta object.

Implemented in PushTechnology.ClientInterface.Data.IDeltaType< TValue, TDelta >.

IBytes PushTechnology.ClientInterface.Data.IDeltaType.ToBytes

(

object

delta

)

Returns the serialized form of the given delta as IBytes.

Since 6.0.

Parameters

delta

The delta object.

Returns

The delta as IBytes.

void PushTechnology.ClientInterface.Data.IDeltaType.WriteDelta	(	object	delta,
		Stream	outputStream
	)

Serializes a delta to binary.

Parameters

delta	The delta object.
outputStream	The output stream.

Property Documentation

string PushTechnology.ClientInterface.Data.IDeltaType.Name

get

Returns the external identifier for this delta type.

object PushTechnology.ClientInterface.Data.IDeltaType.NoChange

get

Returns a constant that indicates no changes between values.

This constant is returned by Diff(object,object) to indicate oldValue and newValue are equivalent. The result is guaranteed to be equal only to itself.

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The documentation for this interface was generated from the following file:

• Data.Public/IDeltaType.cs