Class ExtractorEventTransformer

ExtractorEventTransformer is a special purpose ICacheEventTransformer implementation that transforms emitted events, extracting one or more properties from either the "OldValue" or the "NewValue".

Inheritance

object

ExtractorEventTransformer

Implements

ICacheEventTransformer

IPortableObject

Inherited Members

object.Equals(object, object)

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

Namespace: Tangosol.Util.Transformer

Assembly: Coherence.dll

Syntax

public class ExtractorEventTransformer : ICacheEventTransformer, IPortableObject

Remarks

This transformation will generally result in the change of the values' data type.

Example: the following code will register a listener to receive events only if the value of the "AccountBalance" property changes. The transformed event's "NewValue" will be a IList containing the "LastTransactionTime" and "AccountBalance" properties. The "OldValue" will always be null.

IFilter filter = new ValueChangeEventFilter("AccountBalance");
IValueExtractor extractor = new MultiExtractor("LastTransactionTime,AccountBalance");
ICacheEventTransformer transformer = new ExtractorEventTransformer(null, extractor);
cache.AddCacheListener(listener,
new CacheEventTransformerFilter(filter,
transformer),
false);

Constructors

ExtractorEventTransformer()

Default constructor.

Declaration

public ExtractorEventTransformer()

ExtractorEventTransformer(string)

Construct a ExtractorEventTransformer that transforms CacheEventArgs's values based on the specified method name.

Declaration

public ExtractorEventTransformer(string methodName)

Parameters

Type	Name	Description
string	methodName	The name of the method to invoke via reflection.

Remarks

The name could be a comma-delimited sequence of method names which will result in a MultiExtractor that is based on a corresponding array of IValueExtractor objects; individual array elements will be either ReflectionExtractor or ChainedExtractor objects.

Note: The specified extractor will be applied to both old and new values.

ExtractorEventTransformer(IValueExtractor)

Construct a ExtractorEventTransformer that transforms CacheEventArgs values based on the specified extractor.

Declaration

public ExtractorEventTransformer(IValueExtractor extractor)

Parameters

Type	Name	Description
IValueExtractor	extractor	IValueExtractor to extract CacheEventArgs values.

Remarks

Note: The specified extractor will be applied to both old and new values.

ExtractorEventTransformer(IValueExtractor, IValueExtractor)

Construct a ExtractorEventTransformer that transforms CacheEventArgs values based on the specified extractors.

Declaration

public ExtractorEventTransformer(IValueExtractor extractorOld, IValueExtractor extractorNew)

Parameters

Type	Name	Description
IValueExtractor	extractorOld	Extractor to extract the OldValue property(s).
IValueExtractor	extractorNew	Extractor to extract the NewValue property(s).

Remarks

Passing null indicates that the corresponding values should be skipped completely.

Properties

NewValueExtractor

Return a IValueExtractor used to transfrom the event's NewValue.

Declaration

public virtual IValueExtractor NewValueExtractor { get; }

Property Value

Type	Description
IValueExtractor	An extractor from the NewValue.

OldValueExtractor

Return a IValueExtractor used to transfrom the event's OldValue.

Declaration

public virtual IValueExtractor OldValueExtractor { get; }

Property Value

Type	Description
IValueExtractor	An extractor from the OldValue.

Methods

Equals(object)

Compare the ExtractorEventTransformer with another object to determine equality.

Declaration

public override bool Equals(object o)

Parameters

Type	Name	Description
object	o	The object to compare with the current object.

Returns

Type	Description
bool	true if this ExtractorEventTransformer and the passed object are equivalent.

Overrides

object.Equals(object)

Equals(ExtractorEventTransformer)

Compare the ExtractorEventTransformer with another object to determine equality.

Declaration

public bool Equals(ExtractorEventTransformer that)

Parameters

Type	Name	Description
ExtractorEventTransformer	that	The object to compare with the current object.

Returns

Type	Description
bool	true if this ExtractorEventTransformer and the passed object are equivalent.

GetHashCode()

Determine a hash value for the ExtractorEventTransformer object according to the general Object.GetHashCode contract.

Declaration

public override int GetHashCode()

Returns

Type	Description
int	An integer hash value for this object.

Overrides

object.GetHashCode()

ReadExternal(IPofReader)

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

Declaration

public virtual 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()

Provide a human-readable representation of this object.

Declaration

public override string ToString()

Returns

Type	Description
string	A String whose contents represent the value of this object.

Overrides

object.ToString()

Transform(CacheEventArgs)

Transform the specified CacheEventArgs using the corresponding extractors.

Declaration

public virtual CacheEventArgs Transform(CacheEventArgs eventArgs)

Parameters

Type	Name	Description
CacheEventArgs	eventArgs	CacheEventArgs object to transform.

Returns

Type	Description
CacheEventArgs	A modified CacheEventArgs object that contains extracted values.

WriteExternal(IPofWriter)

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

Declaration

public virtual 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

ICacheEventTransformer

IPortableObject