com.hammurapi.extract

Class IndexedExtractor<T,C>

java.lang.Object

com.hammurapi.extract.IndexedExtractor<T,C>

Type Parameters:

T -

All Implemented Interfaces:

Extractor<T,T,C>, Mappable<T,T,C>

public class IndexedExtractor<T,C>
extends Object
implements Extractor<T,T,C>, Mappable<T,T,C>

Extracts value at index.

Constructor Summary

Constructors

Constructor and Description
IndexedExtractor(int idx)

Method Summary

Methods

Modifier and Type	Method and Description
ComparisonResult	compareTo(Extractor<T,T,C> other) Compares two extractors
boolean	equals(Object obj)
T	extract(C context, Map<C,Map<Extractor<T,? super T,C>,? super T>> cache, T... obj) Extracts value.
double	getCost()
int	getIndex()
int	hashCode()
boolean	isContextDependent()
Extractor<T,T,C>	map(int[] map) Applies mapping to extractor.
Set<Integer>	parameterIndices()
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

IndexedExtractor

public IndexedExtractor(int idx)

Method Detail

parameterIndices

public Set<Integer> parameterIndices()

Specified by:

parameterIndices in interface Extractor<T,T,C>

Returns:

Indexes of objects which this extractor uses for computations.

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

extract

public T extract(C context,
        Map<C,Map<Extractor<T,? super T,C>,? super T>> cache,
        T... obj)

Description copied from interface: Extractor

Extracts value.

Specified by:

extract in interface Extractor<T,T,C>

Parameters:

context - Extraction context. Extraction context may provide source for constants for comparison with object values.

cache - Cache of values extracted from the source object for the given context. Composite extractors can use cache to find already extracted values and to store extracted values. For example extractor which extracts object area as obj.getWidth()*obj.getHeight() may find that width was already extracted and getWidth() doesn't have to be invoked. So it invokes getHeight() and stores returned value to the cache. It also calculates object area and stores it to the cache. A particular cache instance is valid only for a particular obj array, i.e. it can be re-used between extractors but not between arguments.

obj - Source objects.

Returns:

Extracted value.

isContextDependent

public boolean isContextDependent()

Specified by:

isContextDependent in interface Extractor<T,T,C>

Returns:

True if extractor uses context for extraction. False if only object(s) are used.

toString

public String toString()

Overrides:

toString in class Object

compareTo

public ComparisonResult compareTo(Extractor<T,T,C> other)

Description copied from interface: Extractor

Compares two extractors

Specified by:

compareTo in interface Extractor<T,T,C>

Parameters:

other - Other extractor

Returns:

Comparison result.

getCost

public double getCost()

Specified by:

getCost in interface Extractor<T,T,C>

Returns:

Extractor evaluation cost. Cost is used for optimization of computation intensive algorithms. E.g. in Store it is used for selection of indices for query operations.

map

public Extractor<T,T,C> map(int[] map)

Description copied from interface: Mappable

Applies mapping to extractor.

Specified by:

map in interface Mappable<T,T,C>

Returns:

Extractor with changed mapping or null if mapping is not possible.

getIndex

public int getIndex()