package gitlet;

import java.io.File;

import java.io.Serializable;

import java.util.HashMap;

/**

* @author Marco Lyu

* Content: DataPool is a database for all the files committed.

* It avoids the problem of redundancy (same files stored twice.),

* and it keeps users from retrieving serialized files. which should

* be inaccessible to them and modifying these files

*/

public class DataPool implements Serializable {

private static DataPool data = null;

private HashMap<String, File> blobs = new HashMap<String, File>();

/* Only one dataPool can be created */

private DataPool() { }

/* Returns a HashMap containing all the commits */

public static DataPool getPool() {

if (data == null) {

data = new DataPool();

}

return data;

}

/* Puts an entry of a fileId and a file into the HashMap */

public void put(String fileId, File outFile) {

blobs.put(fileId, outFile);

}

/* Retrieves the file according to its fileId */

public File get(String fileId) {

return blobs.get(fileId);

}

/* Checks whether a fileId already exists (avoid redundancy) */

public boolean containsKey(String fileID) {

return blobs.containsKey(fileID);

}

/* Returns the size of the current database */

public int size() {

return blobs.size();

}

}