org.openimaj.ml.annotation.utils

Class AnnotatedListHelper<OBJECT,ANNOTATION>

java.lang.Object

org.openimaj.ml.annotation.utils.AnnotatedListHelper<OBJECT,ANNOTATION>

Type Parameters:

OBJECT - The type of object

ANNOTATION - The type of annotation

public class AnnotatedListHelper<OBJECT,ANNOTATION>
extends Object

Helper class for dealing with lists of annotated objects, and specifically getting objects by class and determining the set of annotations.

Because it might not be practical to hold all the items in the list in memory at once, the implementation only stores the index of each item, and performs an indirect lookup as required. This does mean that once you've passed the list to the constructor, you shouldn't modify it as doing so will invalidate the index. The constructor will make one single pass through all the objects in order to build the index.

Author:

Jonathon Hare (jsh2@ecs.soton.ac.uk)

Constructor Summary

Constructors

Constructor and Description
AnnotatedListHelper(List<? extends Annotated<OBJECT,ANNOTATION>> list) Construct the AnnotatedListHelper with the given list.

Method Summary

Modifier and Type	Method and Description
<FEATURE> List<FEATURE>	extractFeatures(ANNOTATION annotation, FeatureExtractor<FEATURE,OBJECT> extractor) Extract the features corresponding to a specific annotation.
<FEATURE> List<FEATURE>	extractFeaturesExclude(ANNOTATION annotation, FeatureExtractor<FEATURE,OBJECT> extractor) Extract the features corresponding to everything EXCEPT the specific given annotation.
List<Annotated<OBJECT,ANNOTATION>>	get(ANNOTATION annotation) Retrieve all the items from the data that have a specific annotation.
Set<ANNOTATION>	getAnnotations() Get the set of all known annotations

Methods inherited from class java.lang.Object

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

Constructor Detail

AnnotatedListHelper

public AnnotatedListHelper(List<? extends Annotated<OBJECT,ANNOTATION>> list)

Construct the AnnotatedListHelper with the given list.

Parameters:

list - the list

Method Detail

get

public List<Annotated<OBJECT,ANNOTATION>> get(ANNOTATION annotation)

Retrieve all the items from the data that have a specific annotation.

Parameters:

annotation - the annotation to search for.

Returns:

a read-only list of annotated objects with the given annotation.

getAnnotations

public Set<ANNOTATION> getAnnotations()

Get the set of all known annotations

Returns:

the set of known annotations

extractFeatures

public <FEATURE> List<FEATURE> extractFeatures(ANNOTATION annotation,
                                               FeatureExtractor<FEATURE,OBJECT> extractor)

Extract the features corresponding to a specific annotation. This method doesn't actually perform the extraction, rather the returned list will perform the extraction when List.get(int) is called. The returned list doesn't perform any kind of caching, so calling get multiple times on the same object will result in the features being extracted multiple times.

If you need to convert the list to a cached variety, you can write: List cached = new ArrayList(alh.extractFeatures(annotation, extractor));

Type Parameters:

FEATURE - The type of feature

Parameters:

annotation - the annotation

extractor - the feature extractor

Returns:

the list of features.

extractFeaturesExclude

public <FEATURE> List<FEATURE> extractFeaturesExclude(ANNOTATION annotation,
                                                      FeatureExtractor<FEATURE,OBJECT> extractor)

Extract the features corresponding to everything EXCEPT the specific given annotation.

This method doesn't actually perform the extraction, rather the returned list will perform the extraction when List.get(int) is called. The returned list doesn't perform any kind of caching, so calling get multiple times on the same object will result in the features being extracted multiple times.

If you need to convert the list to a cached variety, you can write: List cached = new ArrayList(alh.extractFeatures(annotation, extractor));

Type Parameters:

FEATURE - The type of feature

Parameters:

annotation - the annotation to exclude

extractor - the feature extractor

Returns:

the list of features.