com.tangosol.util.filter

Class ValueChangeEventFilter<V,E>

java.lang.Object

com.tangosol.util.filter.ValueChangeEventFilter<V,E>

All Implemented Interfaces:

ExternalizableLite, PortableObject, Filter<MapEvent<?,V>>, Serializable

public class ValueChangeEventFilter<V,E>
extends Object
implements Filter<MapEvent<?,V>>, ExternalizableLite, PortableObject

Filter which evaluates the content of a MapEvent values based on the specified value extractor. This filter evaluates to true only for update events that change the value of an extracted attribute.

Example: a filter that evaluates to true if there is an update to an Employee object that changes a value of the LastName property.

   new ValueChangeEventFilter("LastName");
 

Since:

Coherence 2.3

Author:

gg 2003.09.30

See Also:

MapEventFilter

Field Summary

Fields

Modifier and Type	Field and Description
protected ValueExtractor<? super V,? extends E>	m_extractor

Constructor Summary

Constructors

Constructor and Description
ValueChangeEventFilter() Default constructor (necessary for the ExternalizableLite interface).
ValueChangeEventFilter(String sMethod) Construct a ValueChangeEventFilter that evaluates MapEvent values based on the specified method name.
ValueChangeEventFilter(ValueExtractor<? super V,? extends E> extractor) Construct a ValueChangeEventFilter that evaluates MapEvent values based on the specified extractor.

Method Summary

Modifier and Type	Method and Description
boolean	equals(Object o) Compare the ValueChangeEventFilter with another object to determine equality.
boolean	evaluate(MapEvent<?,V> event) Apply the test to the input argument.
protected E	extract(V target) Extract value from a target object.
int	hashCode() Determine a hash value for the ValueChangeEventFilter object according to the general Object.hashCode() contract.
void	readExternal(DataInput in) Restore the contents of this object by loading the object's state from the passed DataInput object.
void	readExternal(PofReader in) Restore the contents of a user type instance by reading its state using the specified PofReader object.
String	toString() Return a human-readable description for this Filter.
void	writeExternal(DataOutput out) Save the contents of this object by storing the object's state into the passed DataOutput object.
void	writeExternal(PofWriter out) Save the contents of a POF user type instance by writing its state using the specified PofWriter object.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface com.tangosol.util.Filter

and, asLimitFilter, associatedWith, forKeys, forPartitions, or, xor

Field Detail

m_extractor

protected ValueExtractor<? super V,? extends E> m_extractor

Constructor Detail

ValueChangeEventFilter

public ValueChangeEventFilter()

Default constructor (necessary for the ExternalizableLite interface).

ValueChangeEventFilter

public ValueChangeEventFilter(ValueExtractor<? super V,? extends E> extractor)

Construct a ValueChangeEventFilter that evaluates MapEvent values based on the specified extractor.

Parameters:

extractor - ValueExtractor to extract MapEvent values

ValueChangeEventFilter

public ValueChangeEventFilter(String sMethod)

Construct a ValueChangeEventFilter that evaluates MapEvent values based on the specified method name.

Parameters:

sMethod - the name of the method to invoke via reflection

Method Detail

evaluate

public boolean evaluate(MapEvent<?,V> event)

Apply the test to the input argument.

Specified by:

evaluate in interface Filter<MapEvent<?,V>>

Parameters:

event - the input argument to evaluate

Returns:

true if the input argument matches the filter, otherwise false

extract

protected E extract(V target)

Extract value from a target object.

Parameters:

target - the object to extract the value from

Returns:

the extracted value

equals

public boolean equals(Object o)

Compare the ValueChangeEventFilter with another object to determine equality.

Overrides:

equals in class Object

Returns:

true iff this ValueChangeEventFilter and the passed object are equivalent filters

hashCode

public int hashCode()

Determine a hash value for the ValueChangeEventFilter object according to the general Object.hashCode() contract.

Overrides:

hashCode in class Object

Returns:

an integer hash value for this ValueChangeEventFilter object

toString

public String toString()

Return a human-readable description for this Filter.

Overrides:

toString in class Object

Returns:

a String description of the Filter

readExternal

public void readExternal(DataInput in)
                  throws IOException

Description copied from interface: ExternalizableLite

Restore the contents of this object by loading the object's state from the passed DataInput object.

Specified by:

readExternal in interface ExternalizableLite

Parameters:

in - the DataInput stream to read data from in order to restore the state of this object

Throws:

IOException - if an I/O exception occurs

NotActiveException - if the object is not in its initial state, and therefore cannot be deserialized into

writeExternal

public void writeExternal(DataOutput out)
                   throws IOException

Description copied from interface: ExternalizableLite

Save the contents of this object by storing the object's state into the passed DataOutput object.

Specified by:

writeExternal in interface ExternalizableLite

Parameters:

out - the DataOutput stream to write the state of this object to

Throws:

IOException - if an I/O exception occurs

readExternal

public void readExternal(PofReader in)
                  throws IOException

Description copied from interface: PortableObject

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

Specified by:

readExternal in interface PortableObject

Parameters:

in - the PofReader from which to read the object's state

Throws:

IOException - if an I/O error occurs

writeExternal

public void writeExternal(PofWriter out)
                   throws IOException

Description copied from interface: PortableObject

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

Specified by:

writeExternal in interface PortableObject

Parameters:

out - the PofWriter to which to write the object's state

Throws:

IOException - if an I/O error occurs