org.lenskit.results

Class AbstractResult

java.lang.Object

org.lenskit.results.AbstractResult

All Implemented Interfaces:

Result, KeyedObject

Direct Known Subclasses:

BasicResult, ItemItemResult, OrdRecRatingPredictor.FullResult, RankBlendResult, UserUserResult

public abstract class AbstractResult
extends java.lang.Object
implements Result, KeyedObject

Base class for basic result types. It provides storage for the ID and score, as well as helper methods for hashing and equality checking. This type does not directly enforce immutability, but subclasses should be immutable.

Field Summary

Fields

Modifier and Type	Field and Description
protected long	id
protected double	score

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractResult() Create a new, uninitialized result.
protected	AbstractResult(long id, double score) Create a new result.

Method Summary

Modifier and Type	Method and Description
<T extends Result> T	as(java.lang.Class<T> type) Convert this result to the specified type, if possible.
long	getId() Get the ID for the result.
long	getKey() Get the key for this object.
double	getScore() Get the score (value) associated with this result.
boolean	hasScore() Query whether the result has a score.
protected org.apache.commons.lang3.builder.EqualsBuilder	startEquality(Result r) Create an equality builder, populated with the ID and score.
static org.apache.commons.lang3.builder.EqualsBuilder	startEquality(Result r1, Result r2) Create an equality builder, populated with the ID and score.
protected org.apache.commons.lang3.builder.HashCodeBuilder	startHashCode() Create a hash code builder, populated with the ID and score.
static org.apache.commons.lang3.builder.HashCodeBuilder	startHashCode(Result r) Create an equality builder, populated with the ID and score.

Methods inherited from class java.lang.Object

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

Field Detail

id

protected long id

score

protected double score

Constructor Detail

AbstractResult

protected AbstractResult(long id,
                         double score)

Create a new result.

Parameters:

id - The result ID.

score - The result score.

AbstractResult

protected AbstractResult()

Create a new, uninitialized result.

Method Detail

getKey

public long getKey()

Description copied from interface: KeyedObject

Get the key for this object.

Specified by:

getKey in interface KeyedObject

Returns:

A key identifying this object.

getId

public long getId()

Description copied from interface: Result

Get the ID for the result.

Specified by:

getId in interface Result

Returns:

The user or item ID for this result.

getScore

public double getScore()

Description copied from interface: Result

Get the score (value) associated with this result.

Specified by:

getScore in interface Result

Returns:

The score associated with this entry (or Double.NaN if the result does not have a score).

hasScore

public boolean hasScore()

Description copied from interface: Result

Query whether the result has a score. This is equivalent to testing the return value of Result.getScore() with Double.isNaN(double), but may make the resulting code more readable.

Specified by:

hasScore in interface Result

Returns:

true if the result has a score.

as

public <T extends Result> T as(@Nonnull
                               java.lang.Class<T> type)

Convert this result to the specified type, if possible.

The default implementation simply casts the result to type type if possible.

Specified by:

as in interface Result

Parameters:

type - The desired result type.

Returns:

The result as a result of type T, or null if the type cannot be cast. This may be done by casting this type, or by unwrapping wrapper result types.

startHashCode

protected org.apache.commons.lang3.builder.HashCodeBuilder startHashCode()

Create a hash code builder, populated with the ID and score. Subclasses can use this as a starting point for building a hash code.

Returns:

A hash code builder that has the ID and score already appended.

startEquality

protected org.apache.commons.lang3.builder.EqualsBuilder startEquality(Result r)

Create an equality builder, populated with the ID and score. Subclasses can use this as a starting point for checking equality.

Parameters:

r - The other result.

Returns:

An equality builder, that has the ID and score of this result and r already appended to it.

startEquality

public static org.apache.commons.lang3.builder.EqualsBuilder startEquality(Result r1,
                                                                           Result r2)

Create an equality builder, populated with the ID and score. Subclasses can use this as a starting point for checking equality.

Parameters:

r1 - The first result.

r2 - The other result.

Returns:

An equality builder, that has the ID and score of this result and r already appended to it.

startHashCode

public static org.apache.commons.lang3.builder.HashCodeBuilder startHashCode(Result r)

Create an equality builder, populated with the ID and score. Subclasses can use this as a starting point for checking equality.

Parameters:

r - The other result.

Returns:

An equality builder, that has the ID and score of this result and r already appended to it.