The role of a photo management application is to organize photographs so that they can be easily accessed. In order to help organize photos, the user can provide tags to describe the content of the photos. A tag is a keyword associated with a photo. For example, we can associate the tag ”vacation” to any photo taken during a vacation. In Table 1, you may find some examples of photos and the tags that are used to describe them.
The photo manager organizes the photos into albums created by the user. An album is identified by a unique name and regroups photos that satisfy certain conditions. For the purpose of this assignment, the conditions used to create albums consist in a sequence of tags separated by ”AND”:
Tag1 AND Tag2 AND Tag3
Photos that contain all specified tags will appear in the album. An empty tag list matches all photos.
Example 1. Using the photos of Table 1, the album with the condition bear, will contain two photos (that of the panda and the grizzly bear). The album with the condition animal AND grass will contain four photos (hedgehog, grizzly bear, fox and panda). The albbum with no tags will contain all eight photos.
2. Inverted index
In order to accelerate the search for photos, it is possible to store the tags in an inverted index. The idea is that instead of having the photos point to the tags, the inverted index will store all the tags, and each tag will point to all the photos that contain it.
The following is an example showing a partial inverted index for the photos shown above:
animal → hedgehog.jpg, bear.jpg, fox.jpg, panda.jpg, wolf.jpg, racoon.jpg
apple → hedgehog.jpg
bear → bear.jpg, panda.jpg
black → butterfly2.jpg
butterfly → butterfly1.jpg, butterfly2.jpg
...You are required to:
1. Represent the photos-tags association using an inverted index stored in the class PhotoManager.
2. Use a data structure that allows O(log n) in average to search for a tag.
3 Requirements
You are required to implement the following specification:
public class Photo {
// Constructor
public Photo(String path, LinkedList<String> tags);
// Return the path (full file name) of the photo. A photo is uniquely identified
by its path.
public String getPath();
// Return all tags associated with the photo
public LinkedList<String> getTags();
}
public class Album {
// Constructor
public Album(String name, String condition, PhotoManager manager);
// Return the name of the album
public String getName();
// Return the condition associated with the album
public String getCondition();
// Return the manager
public PhotoManager getManager();
// Return all photos that satisfy the album condition
public LinkedList<Photo> getPhotos();
// Return the number of tag comparisons used to find all photos of the album
public int getNbComps();
}
public class PhotoManager {
// Constructor
public Photomanager();
// Add a photo
public void addPhoto(Photo p);
// Delete a photo
public void deletePhoto(String path);
// Return the inverted index of all managed photos
public BST<LinkedList<Photo>> getPhotos();
}Remark 1. The list of photos that belong to the album is determined at the time when the method getPhotos is called, not when the album is created.
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