Class PofExtractor

POF-based IValueExtractor implementation. PofExtractor takes advantage of POF's indexed state to extract part of an object without needing to deserialize the entire object.

Inheritance

object

AbstractExtractor

PofExtractor

Implements

Inherited Members

AbstractExtractor.Target

AbstractExtractor.Extract(object)

AbstractExtractor.Compare(object, object)

AbstractExtractor.CompareEntries(IQueryCacheEntry, IQueryCacheEntry)

AbstractExtractor.ExtractOriginalFromEntry(CacheEntry)

AbstractExtractor.VALUE

AbstractExtractor.KEY

AbstractExtractor.m_target

object.Equals(object, object)

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

Namespace: Tangosol.Util.Extractor

Assembly: Coherence.dll

Syntax

[Serializable]
public class PofExtractor : AbstractExtractor, IValueExtractor, IQueryCacheComparer, IComparer, IPortableObject

Remarks

POF uses a compact form in the serialized value when possible. For example, some numeric values are represented as special POF intrinsic types in which the type implies the value. As a result, POF requires the receiver of a value to have implicit knowledge of the type. PofExtractor uses the type supplied in the constructor as the source of the type information. If the type is null, PofExtractor will infer the type from the serialized state. Example where extracted value is Double:

IValueExtractor extractor = new PofExtractor(typeof(Double), 2);

Example where extracted value should be inferred:

IValueExtractor extractor = new PofExtractor(null, 2);

Constructors

PofExtractor()

Default constructor.

Declaration

public PofExtractor()

PofExtractor(Type, int)

Constructs a PofExtractor based on a property index.

Declaration

public PofExtractor(Type type, int index)

Parameters

Type	Name	Description
Type	type	The required type of the extracted value or `null` if the type is to be inferred from the serialized state.
int	index	Property index.

Remarks

This constructor is equivalent to:

PofExtractor extractor = 
    new PofExtractor(type, new SimplePofPath(index), VALUE);

PofExtractor(Type, IPofNavigator)

Constructs a PofExtractor based on a POF navigator.

Declaration

public PofExtractor(Type type, IPofNavigator navigator)

Parameters

Type	Name	Description
Type	type	The required type of the extracted value or `null` if the type is to be inferred from the serialized state.
IPofNavigator	navigator	POF navigator.

PofExtractor(Type, IPofNavigator, int)

Constructs a PofExtractor based on a POF navigator and the entry extraction target.

Declaration

public PofExtractor(Type type, IPofNavigator navigator, int target)

Parameters

Type	Name	Description
Type	type	The required type of the extracted value or `null` if the type is to be inferred from the serialized state.
IPofNavigator	navigator	POF navigator.
int	target	One of the VALUE or KEY values.

Properties

Navigator

Obtain the IPofNavigator for this extractor.

Declaration

public IPofNavigator Navigator { get; }

Property Value

Type	Description
IPofNavigator

TypeExtracted

Obtain the type of the extracted value.

Declaration

public Type TypeExtracted { get; }

Property Value

Type	Description
Type	The expected type.

Methods

Equals(object)

Compare the PofExtractor with another object to determine equality.

Declaration

public override bool Equals(object o)

Parameters

Type	Name	Description
object	o	Object to compare with

Returns

Type	Description
bool	true iff this PofExtractor and the passed object are equivalent

Overrides

object.Equals(object)

Remarks

Two PofExtractor objects are considered equal iff their paths are equal and they have the same target (key or value).

ExtractFromEntry(ICacheEntry)

Extracts the value from the passed ICacheEntry object.

Declaration

public override object ExtractFromEntry(ICacheEntry entry)

Parameters

Type	Name	Description
ICacheEntry	entry	An Entry object to extract a value from

Returns

Type	Description
object	The extracted value

Overrides

AbstractExtractor.ExtractFromEntry(ICacheEntry)

Remarks

This method will always throw a NotSupportedException if called directly by the .NET client application, as its execution is only meaningful within the cluster.

It is expected that this extractor will only be used against POF-encoded binary entries within a remote partitioned cache.

Exceptions

Type	Condition
NotSupportedException	Always, as it is expected that this extractor will only be executed within the cluster.

GetHashCode()

Determine a hash value for the PofExtractor object.

Declaration

public override int GetHashCode()

Returns

Type	Description
int	An integer hash value for this PofExtractor object

Overrides

object.GetHashCode()

GetPofTypeId(IPofContext)

Compute the expected pof type id based on the type.

Declaration

protected int GetPofTypeId(IPofContext ctx)

Parameters

Type	Name	Description
IPofContext	ctx	Pof context.

Returns

Type	Description
int	Pof type id or T_UNKNOWN if the type is `null`.

ReadExternal(IPofReader)

Restore the contents of a user type instance by reading its state using the specified IPofReader object.

Declaration

public void ReadExternal(IPofReader reader)

Parameters

Type	Name	Description
IPofReader	reader	The IPofReader from which to read the object's state.

Exceptions

Type	Condition
IOException	If an I/O error occurs.

ToString()

Return a human-readable description for this PofExtractor.

Declaration

public override string ToString()

Returns

Type	Description
string	String description of the PofExtractor

Overrides

object.ToString()

WriteExternal(IPofWriter)

Save the contents of a POF user type instance by writing its state using the specified IPofWriter object.

Declaration

public void WriteExternal(IPofWriter writer)

Parameters

Type	Name	Description
IPofWriter	writer	The IPofWriter to which to write the object's state.

Exceptions

Type	Condition
IOException	If an I/O error occurs.

Implements

IValueExtractor

IQueryCacheComparer

IComparer

IPortableObject