org.lenskit.results

Class Results

java.lang.Object

org.lenskit.results.Results

public final class Results
extends java.lang.Object

Utility functions for working with results.

Method Summary

Modifier and Type	Method and Description
static BasicResult	basicCopy(Result r) Create a basic result that has the same ID and score as another result (a basic copy of the result).
static Function<Result,BasicResult>	basicCopyFunction() Guava function that converts a result to a basic result.
static Equivalence<Result>	basicEquivalence() An equivalence relation that considers objects to be equal if they are equal after being converted to basic results (that is, their IDs and scores are equal).
static BasicResult	create(long id, double score) Create a new result with just and ID and a score.
static BasicResult	fromEntry(java.util.Map.Entry<java.lang.Long,java.lang.Double> entry) Convert a map entry to a basic result.
static Function<java.util.Map.Entry<java.lang.Long,java.lang.Double>,Result>	fromEntryFunction() Function to convert map entries to basic results.
static Ordering<Result>	idOrder() Get an ordering (comparator) that orders results by ID.
static KeyExtractor<Result>	keyExtractor() Get a key extractor that extracts the result’s ID as its key.
static java.util.stream.Collector<Result,?,ResultList>	listCollector() A Java 8 collector that makes result lists.
static ResultList	newResultList(java.util.List<? extends Result> results) Create a new result list.
static <R extends Result> ResultList	newResultList(R... results) Create a new result list.
static BasicResultMap	newResultMap(java.lang.Iterable<? extends Result> results) Create a new result list.
static <R extends Result> BasicResultMap	newResultMap(R... results) Create a new result list.
static RescoredResult	rescore(Result r, double s) Create a rescored result.
static RescoredResult	rescore(Result orig, Result score) Create a rescored result with details.
static Ordering<Result>	scoreOrder() Get an ordering (comparator) that orders results by score.

Methods inherited from class java.lang.Object

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

Method Detail

create

public static BasicResult create(long id,
                                 double score)

Create a new result with just and ID and a score.

Parameters:

id - The ID.

score - The score.

Returns:

The result instance.

basicCopy

public static BasicResult basicCopy(Result r)

Create a basic result that has the same ID and score as another result (a basic copy of the result).

Parameters:

r - The result to copy.

Returns:

A basic result with the same ID and score as r. This may be the same object as r, since basic results are immutable.

rescore

public static RescoredResult rescore(Result r,
                                     double s)

Create a rescored result.

Parameters:

r - The result to score.

s - The new score.

Returns:

A RescoredResult that wraps r with a new score of s.

rescore

public static RescoredResult rescore(@Nonnull
                                     Result orig,
                                     @Nullable
                                     Result score)

Create a rescored result with details.

Parameters:

orig - The original result.

score - The new result, or null for no score (the resulting result will have no score).

Returns:

A rescored result with the ID but the new score.

newResultList

@Nonnull
public static ResultList newResultList(@Nonnull
                                                java.util.List<? extends Result> results)

Create a new result list.

Parameters:

results - The results to include in the list.

Returns:

The result list.

newResultList

@SafeVarargs
 @Nonnull
public static <R extends Result> ResultList newResultList(R... results)

Create a new result list.

Parameters:

results - The results to include in the list.

R - the result type

Returns:

The result list.

newResultMap

@Nonnull
public static BasicResultMap newResultMap(@Nonnull
                                                   java.lang.Iterable<? extends Result> results)

Create a new result list.

Parameters:

results - The results to include in the list.

Returns:

The result list.

newResultMap

@SafeVarargs
 @Nonnull
public static <R extends Result> BasicResultMap newResultMap(R... results)

Create a new result list.

Parameters:

results - The results to include in the list.

R - the result type

Returns:

The result list.

listCollector

public static java.util.stream.Collector<Result,?,ResultList> listCollector()

A Java 8 collector that makes result lists.

Returns:

A new result list collector.

basicCopyFunction

public static Function<Result,BasicResult> basicCopyFunction()

Guava function that converts a result to a basic result. This is just basicCopy(Result) exposed as a Guava Function for use in processing lists, etc.

Returns:

A function that maps results to basic (only score and ID) versions of them.

fromEntry

public static BasicResult fromEntry(java.util.Map.Entry<java.lang.Long,java.lang.Double> entry)

Convert a map entry to a basic result.

Parameters:

entry - The map entry.

Returns:

The basic result.

fromEntryFunction

public static Function<java.util.Map.Entry<java.lang.Long,java.lang.Double>,Result> fromEntryFunction()

Function to convert map entries to basic results.

Returns:

A function that converts map entries to basic results.

basicEquivalence

public static Equivalence<Result> basicEquivalence()

An equivalence relation that considers objects to be equal if they are equal after being converted to basic results (that is, their IDs and scores are equal).

Returns:

The equivalence relation.

idOrder

public static Ordering<Result> idOrder()

Get an ordering (comparator) that orders results by ID.

Returns:

An ordering that orders results by ID (increasing).

scoreOrder

public static Ordering<Result> scoreOrder()

Get an ordering (comparator) that orders results by score.

Returns:

An ordering that orders results by score (increasing).

keyExtractor

public static KeyExtractor<Result> keyExtractor()

Get a key extractor that extracts the result’s ID as its key.

Returns:

The key extractor.