Interface IDeltaType<TValue, TDelta>

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

Inherited Members
Namespace: PushTechnology.ClientInterface.Data
Assembly: Diffusion.Client.dll
Syntax
public interface IDeltaType<TValue, TDelta> : IDeltaType
Type Parameters
Name Description
TValue

The value type.
TDelta

The delta type.
Remarks

This is a generic version of the IDeltaType interface that provides overloads for all object methods. It instead provides typed arguments and return values based on the given value and delta type.

For more information about the delta type interface, see IDeltaType.

Since 5.8

Properties

NoChange

Returns a constant that indicates no changes between values.

Declaration
TDelta NoChange { get; }
Property Value
Type Description
TDelta

A constant that indicates no changes between values.
Remarks

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

Methods

Apply(TValue, TDelta)

Applies a delta to a value.

Declaration
TValue Apply(TValue oldValue, TDelta delta)
Parameters
Type Name Description
TValue oldValue

The old value.
TDelta delta

The delta to apply to the old value.
Returns
Type Description
TValue

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

Diff(TValue, TValue)

Creates a delta from two values.

Declaration
TDelta Diff(TValue oldValue, TValue newValue)
Parameters
Type Name Description
TValue oldValue

The old value.
TValue newValue

The new value.
Returns
Type Description
TDelta

The delta representing the difference between oldValue and newValue.
Remarks

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(TValue, TDelta).

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

IsValueCheaper(TValue, TDelta)

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.

Declaration
bool IsValueCheaper(TValue value, TDelta delta)
Parameters
Type Name Description
TValue value

The value.
TDelta delta

The delta.
Returns
Type Description
System.Boolean

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

ReadDelta(IBytes)

Creates a delta from IBytes.

Declaration
TDelta ReadDelta(IBytes input)
Parameters
Type Name Description
IBytes input

The binary data.
Returns
Type Description
TDelta

The delta object.
Remarks

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

Since 6.0.

ReadDelta(Byte[])

Parses a delta from a binary.

Declaration
TDelta ReadDelta(byte[] input)
Parameters
Type Name Description
System.Byte[] input

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

The delta.
Remarks

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

ReadDelta(Byte[], Int32, Int32)

Parses a delta from a binary segment.

Declaration
TDelta ReadDelta(byte[] input, int offset, int length)
Parameters
Type Name Description
System.Byte[] input

The binary data. The implementation may re-use the array to avoid copying. The caller must ensure the array is not modified.
System.Int32 offset

The starting index of the segment.
System.Int32 length

The length of the segment.
Returns
Type Description
TDelta

The delta.

ToBytes(TDelta)

Returns the serialized form of the given delta as IBytes.

Declaration
IBytes ToBytes(TDelta delta)
Parameters
Type Name Description
TDelta delta

The delta object.
Returns
Type Description
IBytes

The delta as IBytes.
Remarks

Since 6.0.

WriteDelta(TDelta, Stream)

Serializes a delta to binary.

Declaration
void WriteDelta(TDelta delta, Stream outputStream)
Parameters
Type Name Description
TDelta delta

The delta.
Stream outputStream

The output stream.