com.espertech.esper.filter

Class FilterParamIndexBase

java.lang.Object

com.espertech.esper.filter.FilterParamIndexBase

All Implemented Interfaces:

EventEvaluator

Direct Known Subclasses:

FilterParamIndexBooleanExpr, FilterParamIndexLookupableBase

public abstract class FilterParamIndexBase
extends Object
implements EventEvaluator

Each implementation of this abstract class represents an index of filter parameter constants supplied in filter parameters in filter specifications that feature the same event property and operator.

For example, a filter with a parameter of "count EQUALS 10" would be represented as index for a property named "count" and for a filter operator typed "EQUALS". The index would store a value of "10" in its internal structure.

Implementations make sure that the type of the Object constant in get and put calls matches the event property type.

Constructor Summary

Constructors

Constructor and Description
FilterParamIndexBase(FilterOperator filterOperator) Constructor.

Method Summary

Modifier and Type	Method and Description
abstract EventEvaluator	get(Object filterConstant) Get the event evaluation instance associated with the constant.
FilterOperator	getFilterOperator() Returns the filter operator that the index matches for.
abstract ReadWriteLock	getReadWriteLock() Supplies the lock for protected access.
abstract boolean	isEmpty() Return empty indicator.
abstract void	put(Object filterConstant, EventEvaluator evaluator) Store the event evaluation instance for the given constant.
abstract void	remove(Object filterConstant) Remove the event evaluation instance for the given constant.
abstract int	sizeExpensive() Return the number of distinct filter parameter constants stored, which can be an expensive call.
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface com.espertech.esper.filter.EventEvaluator

matchEvent

Constructor Detail

FilterParamIndexBase

public FilterParamIndexBase(FilterOperator filterOperator)

Constructor.

Parameters:

filterOperator - is the type of comparison performed.

Method Detail

get

public abstract EventEvaluator get(Object filterConstant)

Get the event evaluation instance associated with the constant. Returns null if no entry found for the constant. The calling class must make sure that access to the underlying resource is protected for multi-threaded access, the getReadWriteLock() method must supply a lock for this purpose.

Parameters:

filterConstant - is the constant supplied in the event filter parameter

Returns:

event evaluator stored for the filter constant, or null if not found

put

public abstract void put(Object filterConstant,
                         EventEvaluator evaluator)

Store the event evaluation instance for the given constant. Can override an existing value for the same constant. The calling class must make sure that access to the underlying resource is protected for multi-threaded access, the getReadWriteLock() method must supply a lock for this purpose.

Parameters:

filterConstant - is the constant supplied in the filter parameter

evaluator - to be stored for the constant

remove

public abstract void remove(Object filterConstant)

Remove the event evaluation instance for the given constant. Returns true if the constant was found, or false if not. The calling class must make sure that access to the underlying resource is protected for multi-threaded writes, the getReadWriteLock() method must supply a lock for this purpose.

Parameters:

filterConstant - is the value supplied in the filter paremeter

sizeExpensive

public abstract int sizeExpensive()

Return the number of distinct filter parameter constants stored, which can be an expensive call. The calling class must make sure that access to the underlying resource is protected for multi-threaded writes, the getReadWriteLock() method must supply a lock for this purpose.

Returns:

Number of entries in index

isEmpty

public abstract boolean isEmpty()

Return empty indicator. The calling class must make sure that access to the underlying resource is protected for multi-threaded writes, the getReadWriteLock() method must supply a lock for this purpose.

Returns:

empty flag

getReadWriteLock

public abstract ReadWriteLock getReadWriteLock()

Supplies the lock for protected access.

Returns:

lock

getFilterOperator

public final FilterOperator getFilterOperator()

Returns the filter operator that the index matches for.

Returns:

filter operator

toString

public String toString()

Overrides:

toString in class Object