question archive The Author Class The Author class represents an author who wrote and published at least one paper that is available at the Paper DB
The Author Class The Author class represents an author who wrote and published at least one paper that is available at the Paper DB
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The Author Class
The Author class represents an author who wrote and published at least one paper that is available at the Paper DB.
Do the following in the Author class:
- • Add a papers attribute which is an ArrayList of Paper objects. This list will contain all the papers that this author has written and to be made available to the Paper DB community. Adjust the 2nd constructor to ensure that this attribute is initialized properly. a get method for the attribute.
- • Adjust the toString() method so that the '#' is replaced by the number of papers written by this author.
- • a method called addPaper(Paper p, PaperDB pdb) which adds a given paper to this author's paper list and updates the HashMaps on pdb.
The Paper Class
The Paper class represents a paper that is available at the Paper DB and a registered author of the Paper DB can download this paper.
Do the following in the Paper class:
- • Add authors attribute which is an ArrayList of Author objects. This list will contain one or more authors of this paper. Adjust the 2nd constructor to ensure that this attribute is initialized properly.a get method for the attribute as well.
- • Adjust the toString() method so that it shows the authors of this paper.
The PaperDB Class
The class called PaperDB represents the online database where authors can register themselves to share their papers and download papers published by other authors. The class should have the following attributes:
- • allRegisteredAuthors - an ArrayList of all registered Authors.
- • byTitle - a HashMap of type <String, Paper>, where keys are the title of the paper.
- • byAuthor - a HashMap of type <Author, ArrayList<Paper>>, where a key is the author of all papers stored in the ArrayList<Paper>.
- • byConference - a HashMap of type <String, ArrayList<Paper>>, where a key is the conference that published all papers stored in the ArrayList<Paper>.
Create the following methods:
- • Adjust the 2nd constructor to ensure that all attributes are initialized properly. a get method for these attributes.
- • A authorWithName(String s) method that finds and returns the author object with the given name if it is in the list of authors. If not there, null should be returned.
- A registerAuthor(Author a) method that adds a given Author to the Paper DB's list of registered authors, provided that there are no other author with the same authorName. If there are other users with the same authorName, then this method does nothing. Use the authorWithName(String s) method above. Then for each paper in the papers ArrayList of this author, update the HashMap(s) (byTitle, byAuthor, byConference).
- • Adjust the toString() method that shows the number of registered authors (#).
Go back to the Author class and add these methods:
- • register(PaperDB pdb) that makes use of the registerAuthor(Author author) method that you just wrote to register the author into the given PaperDB pdb. The registered attribute of this author should now set to true.
- • requestAllRegisteredAuthors(PaperDB pdb) method that returns the list of all authors currently registered with pdb
- • requestAllDownloadablePapers(PaperDB pdb) method that should gather the list of all available papers (no duplicate papers) where at least one of the authors has registered with pdb and then return an ArrayList<String> formatted as follows (note: there should be 1 String element in the ArrayList per line).
1. "How to a paper" by Ains Tain, John Doe, published in ABC conference
Now you should test your code. To do so, run the PaperDBTestProgram1.java file and compare your results to the expected results below.
Here is the output that you should see:
Status: DBLP Paper DB with 0 registered authors
All registerd Authors: []
All downloadable Papers:
None
Status: DBLP Paper DB with 4 registered authors
All registerd Authors: [Ains Tain: 3 papers (registered), Bugs Bunny: 3 papers (registered), Robin Road: 2 papers (registered), Peter Pan: 2 papers (registered)]
All downloadable Papers:
1. "How to a paper" by Ains Tain, John Doe, published in ABC conference
2. "A Nice Paper" by Ains Tain, published in SODA II
3. "Very Short paper" by Ains Tain, published in IEEE Mini
4. "How to survive first year comp sci" by Bugs Bunny, published in WALCOMP
5. "Neural Nets: Say Hi to Our Future Machine Overlords" by Bugs Bunny, published in CYBORG
6. "Useless graphs and how to draw them" by Bugs Bunny, published in Graph Drawing
7. "A boring paper" by Robin Road, published in ABC conference
8. "A Funny Paper" by Peter Pan, Robin Road, published in CALLDAM
9. "Art of selling your paper" by Peter Pan, published in XYZ conference
10. "A Funny Paper" by Peter Pan, Robin Road, published in CALLDAM
Go back to the Author class and add these methods:
- • An requestAllPapersByAuthor(PaperDB pdb, String authorName) method that returns a new ArrayList of all papers by the specified author currently registered in pdb for download. Note that this method creates and then returns an ArrayList<String> formatted similar to that shown above.
- • A requestAllPapersByAuthors(PaperDB pdb, String ... authorNames) method that returns a new ArrayList of all papers published by all authors in authorNames (all authors must be registered). That is, if the authors are "Steve", "Louis", every paper returned should have both authors listed.
- • Note: in String... the three dots indicate a variable number of arguments, i.e., a list of Strings in this case, which can be received/used as an array of Strings inside the method
Now, run the PaperDBTestProgram2.java file and compare your results to the expected results below.
Author with name Ains Tain: Ains Tain: 3 papers (registered)
All papers by Ains Tain
1. "How to a paper" by Ains Tain, John Doe, published in ABC conference
2. "A Nice Paper" by Ains Tain, published in SODA II
3. "Very Short paper" by Ains Tain, published in IEEE Mini
Author with name Ains Tain: Ains Tain: 4 papers (registered)
All papers by Ains Tain after adding P10
1. "How to a paper" by Ains Tain, John Doe, published in ABC conference
2. "A Nice Paper" by Ains Tain, published in SODA II
3. "Very Short paper" by Ains Tain, published in IEEE Mini
4. "Useless graphs and how to draw them" by Bugs Bunny, Ains Tain, published in Graph Drawing
All Papers by Bugs Bunny, Ains Tain & John Doe
Papers not available
All Papers by Bugs Bunny & Ains Tain
"Useless graphs and how to draw them" by Bugs Bunny, Ains Tain, published in Graph Drawing
All Papers by Robin Road & Peter Pan
"A Funny Paper" by Peter Pan, Robin Road, published in CALLDAM
4. Downloading Papers
In the Author class, add the following methods:
- • A downloadPaper(PaperDB pdb, String title) method that simulates the downloading of one of the papers from the list of all downloadable papers. Only a registered author can download a paper written by other authors (i.e., it cannot be author's own paper).
Add the following attribute to the PaperDB class:
- • allDownloadedPapers - an ArrayList of all papers downloaded from this website. This list will, in general, contain duplicate Paper objects.
Add the following method to the PaperDB class:
- • updateDownloadedPapers(Paper p) method that updates the allDownloadedPapers arrayList for each downloaded paper.
- • Adjust the downloadPaper(PaperDB pdb, String title) method from Author class so the pdb can update the allDownloadedPapers ArrayList. Use the method you just wrote for this in PaperDB class.
- •get a method in the PaperDB class called uniqueDownloads() that returns (i.e., not displays) a TreeSet of all downloaded Paper objects such that the set is sorted alphabetically by their titles. There should be no duplicates papers in this set. To add the Paper objects to the TreeSet, the Paper class will need to implement Comparable<Paper> and you will need to write the corresponding compareTo(Paper p) method in the Paper class.
5. Bonus
- • need a method in the PaperDB class called papersByPopularity() that returns (i.e., not displays) an ArrayList of Pair<Integer,Paper> objects, where the key of the pair is an Integer representing the number of downloads and the value is the Paper object. The integer key should represent the number of times that the paper was downloaded. The list
- returned should be sorted in decreasing order according to the number of times the paper was downloaded. To sort a list of Pair objects, you can use the following code:
Collections.sort(yourListOfPairs, new Comparator<Pair<Integer, Paper>>() {
public int compare(Pair<Integer, Paper> p1, Pair<Integer, Paper> p2) {
// PUT YOUR CODE IN HERE
}
});
Insert the missing code so that it returns an appropriate integer indicating whether pair p1 comes before or after pair p2 in the sort order (see notes, Chapter 8, Page 281).
Run the PaperDBTestProgram3.java test file to make sure it works with your code.
Here is the expected output:
Here are the downloaded papers:
"A Funny Paper" by Peter Pan, Robin Road, published in CALLDAM
"Art of selling your paper" by Peter Pan, published in XYZ conference
"A Nice Paper" by Ains Tain, published in SODA II
"A Nice Paper" by Ains Tain, published in SODA II
"Very Short paper" by Ains Tain, published in IEEE Mini
"How to survive first year comp sci" by Bugs Bunny, published in WALCOMP
"A Nice Paper" by Ains Tain, published in SODA II
"Very Short paper" by Ains Tain, published in IEEE Mini
Here are the unique downloaded papers alphabetically:
"A Funny Paper" by Peter Pan, Robin Road, published in CALLDAM
"A Nice Paper" by Ains Tain, published in SODA II
"Art of selling your paper" by Peter Pan, published in XYZ conference
"How to survive first year comp sci" by Bugs Bunny, published in WALCOMP
"Very Short paper" by Ains Tain, published in IEEE Mini
Here are the downloaded papers by populariry (BONUS):
(3 downloads) "A Nice Paper" by Ains Tain, published in SODA II
(2 downloads) "Very Short paper" by Ains Tain, published in IEEE Mini
(2 downloads) "A Funny Paper" by Peter Pan, Robin Road, published in CALLDAM
(1 downloads) "Art of selling your paper" by Peter Pan, published in XYZ conference
(1 downloads) "How to survive first year comp sci" by Bugs Bunny, published in WALCOMP
(0 downloads) "How to wrote a paper" by Ains Tain, John Doe, published in ABC conference
- (0 downloads) "Triangles and Squares: A preschool analysis" by John Doe, published in CCCG
(0 downloads) "A boring paper" by Robin Road, published in ABC conference
(0 downloads) "Neural Nets: Say Hi to Our Future Machine Overlords" by Bugs Bunny, published in CYBORG
(0 downloads) "Useless graphs and how to draw them" by Bugs Bunny, published in Graph Drawing
import java.util.ArrayList;
public class Author {
private String authorName;
private boolean registered;
ArrayList<Paper> papers;
public Author() { this("");}
public Author(String aName) {
//todo: complete
authorName = aName;
registered = false;
papers=new ArrayList<Paper>();
}
public ArrayList<Paper> getPapers(){
return papers;
}
public String getAuthorName() { return authorName; }
public boolean isRegistered() { return registered; }
//TODO: complete code
public String toString() {
String s = "" + authorName + ": "+ "#" + " papers (";
if (!registered) s += "not ";
return s + "registered)";
}
public void addPaper(Paper p, PaperDB pdb){
//todo:complete
if(!papers.contains(p)){
papers.add(p);
}
}
}
import java.util.ArrayList;
public class Paper {
private String title;
private String conference;
ArrayList<Author>authors;
public Paper() {
this("","");
}
public Paper(String t, String c) {
title = t;
conference = c;
authors=new ArrayList<Author>();
}
public ArrayList<Author> getAuthors(){ return authors; }
public String getTitle() {
return title;
}
public String getConference() {
return conference;
}
//TODO: complete code
public String toString() {
String result = """ + title + "" by ";
result += "published in " + conference+"author is "+authors;
return result;
}
}
import java.util.ArrayList;
import java.util.HashMap;
public class PaperDB {
private String name;
ArrayList<Author>allRegisteredAuthors;
private HashMap<String, Paper> titleList;
private HashMap <Author, ArrayList<Paper>>authorList;
private HashMap<String, ArrayList<Paper>> conferenceList;
public PaperDB(){this("");}
public PaperDB(String aName) {
name = aName;
//TODO: instantiate all the member variables
allRegisteredAuthors=new ArrayList<>();
titleList=new HashMap<String, Paper>();
authorList=new HashMap<Author, ArrayList<Paper>>();
conferenceList=new HashMap<String,ArrayList<Paper>>();
}
public HashMap<String,Paper> getTitleList() { return titleList; }
public HashMap<Author,ArrayList<Paper>> getAuthorList() { return authorList; }
public HashMap<String,ArrayList<Paper>> getConferenceList() { return conferenceList; }
public String getName() {
return name;
}
// public String authorWithName(String s){
// if(!authorList.isEmpty()){
//
// }
// return null;
// }
// public Author registerAuthor(Author a){
// allRegisteredAuthors.add(a);
//
// }
//TODO: complete code
public String toString(){
return this.name + "Paper DB with # registered authors";
}
}
import java.util.ArrayList;
public class PaperDBTestProgram1 {
public static void main(String args[]) {
// Create a new paper database
PaperDB pdb = new PaperDB("DBLP");
ArrayList<String> list = new ArrayList<String>();
// Create some authors
Author ainsTain = new Author("Ains Tain");
Author johnDoe = new Author("John Doe");
Author peterPan = new Author("Peter Pan");
Author robinRoad = new Author("Robin Road");
Author bugsBunny = new Author("Bugs Bunny");
// Create some papers
Paper p1 = new Paper("How to write a paper", "ABC conference");
Paper p2 = new Paper("Triangles and Squares: A preschool analysis", "CCCG");
Paper p3 = new Paper("A Nice Paper", "SODA II");
Paper p4 = new Paper("Very Short paper", "IEEE Mini");
Paper p5 = new Paper("A boring paper", "ABC conference");
Paper p6 = new Paper("How to survive first year comp sci", "WALCOMP");
Paper p7 = new Paper("Neural Nets: Say Hi to Our Future Machine Overlords", "CYBORG");
Paper p8 = new Paper("Art of selling your paper", "XYZ conference");
Paper p9 = new Paper("A Funny Paper", "CALLDAM");
Paper p10 = new Paper("Useless graphs and how to draw them", "Graph Drawing");
//add papers to authors
ainsTain.addPaper(p1, pdb);
ainsTain.addPaper(p3, pdb);
ainsTain.addPaper(p4, pdb);
johnDoe.addPaper(p1, pdb);
johnDoe.addPaper(p2, pdb);
peterPan.addPaper(p8, pdb);
peterPan.addPaper(p9, pdb);
robinRoad.addPaper(p5, pdb);
robinRoad.addPaper(p9, pdb);
bugsBunny.addPaper(p6, pdb);
bugsBunny.addPaper(p7, pdb);
bugsBunny.addPaper(p10, pdb);
// Display the state of things before any author registers
System.out.println("Status: " + pdb);
System.out.println("All registerd Authors: " +
bugsBunny.requestAllRegisteredAuthors(pdb));
System.out.println("All downloadable Papers: ");
list = bugsBunny.requestAllDownloadablePapers(pdb);
if(list.size() == 0) System.out.println("None");
else {
for (String line : list) {
System.out.println(line);
}
}
System.out.println();
// Register the authors, except johnDoe
ainsTain.register(pdb);
bugsBunny.register(pdb);
robinRoad.register(pdb);
peterPan.register(pdb);
// Display the state of things after some authors register
System.out.println("Status: " + pdb);
System.out.println("All registerd Authors: " +
bugsBunny.requestAllRegisteredAuthors(pdb));
System.out.println("All downloadable Papers: ");
list = bugsBunny.requestAllDownloadablePapers(pdb);
if(list.size() == 0) System.out.println("None");
else {
for (String line : list) {
System.out.println(line);
}
}
System.out.println();
}
}
import java.util.ArrayList;
public class PaperDBTestProgram2 {
public static void main(String args[]) {
// Create a new paper database
PaperDB pdb = new PaperDB("DBLP");
ArrayList<String> list = new ArrayList<String>();
// Create some authors
Author ainsTain = new Author("Ains Tain");
Author johnDoe = new Author("John Doe");
Author peterPan = new Author("Peter Pan");
Author robinRoad = new Author("Robin Road");
Author bugsBunny = new Author("Bugs Bunny");
// Create some papers
Paper p1 = new Paper("How to write a paper", "ABC conference");
Paper p2 = new Paper("Triangles and Squares: A preschool analysis", "CCCG");
Paper p3 = new Paper("A Nice Paper", "SODA II");
Paper p4 = new Paper("Very Short paper", "IEEE Mini");
Paper p5 = new Paper("A boring paper", "ABC conference");
Paper p6 = new Paper("How to survive first year comp sci", "WALCOMP");
Paper p7 = new Paper("Neural Nets: Say Hi to Our Future Machine Overlords", "CYBORG");
Paper p8 = new Paper("Art of selling your paper", "XYZ conference");
Paper p9 = new Paper("A Funny Paper", "CALLDAM");
Paper p10 = new Paper("Useless graphs and how to draw them", "Graph Drawing");
//add papers to authors
ainsTain.addPaper(p1, pdb);
ainsTain.addPaper(p3, pdb);
ainsTain.addPaper(p4, pdb);
johnDoe.addPaper(p1, pdb);
johnDoe.addPaper(p2, pdb);
peterPan.addPaper(p8, pdb);
peterPan.addPaper(p9, pdb);
robinRoad.addPaper(p5, pdb);
robinRoad.addPaper(p9, pdb);
bugsBunny.addPaper(p6, pdb);
bugsBunny.addPaper(p7, pdb);
bugsBunny.addPaper(p10, pdb);
// Register the authors, except johnDoe
ainsTain.register(pdb);
bugsBunny.register(pdb);
robinRoad.register(pdb);
peterPan.register(pdb);
//search
System.out.println("Author with name Ains Tain: " + pdb.authorWithName("Ains Tain"));
System.out.println("All papers by Ains Tain");
list = bugsBunny.requestAllPapersByAuthor(pdb, "Ains Tain");
for(String line: list){
System.out.println(line);
}
System.out.println();
ainsTain.addPaper(p10,pdb);
System.out.println("Author with name Ains Tain: " + pdb.authorWithName("Ains Tain"));
System.out.println("All papers by Ains Tain after adding P10");
list = bugsBunny.requestAllPapersByAuthor(pdb, "Ains Tain");
for(String line: list){
System.out.println(line);
}
System.out.println();
ArrayList<Paper> paperList;
//No papers should be available - John Doe is not registered
paperList = bugsBunny.requestAllPapersByAuthors(pdb,"Bugs Bunny","Ains Tain","John Doe");
System.out.println("All Papers by Bugs Bunny, Ains Tain & John Doe");
if(paperList.isEmpty()) System.out.println("Papers not available");
else{for(Paper p: paperList)
System.out.println(p);}
System.out.println();
paperList = bugsBunny.requestAllPapersByAuthors(pdb,"Bugs Bunny","Ains Tain");
System.out.println("All Papers by Bugs Bunny & Ains Tain");
if(paperList.isEmpty()) System.out.println("Papers not available");
else{for(Paper p: paperList)
System.out.println(p);}
System.out.println();
paperList = bugsBunny.requestAllPapersByAuthors(pdb,"Robin Road","Peter Pan");
System.out.println("All Papers by Robin Road & Peter Pan");
if(paperList.isEmpty()) System.out.println("Papers not available");
else{for(Paper p: paperList)
System.out.println(p);}
}
}
import java.util.ArrayList;
public class PaperDBTestProgram3 {
public static void main(String args[]) {
// Create a new paper database
PaperDB pdb = new PaperDB("DBLP");
ArrayList<String> list = new ArrayList<String>();
// Create some authors
Author ainsTain = new Author("Ains Tain");
Author johnDoe = new Author("John Doe");
Author peterPan = new Author("Peter Pan");
Author robinRoad = new Author("Robin Road");
Author bugsBunny = new Author("Bugs Bunny");
// Create some papers
Paper p1 = new Paper("How to write a paper", "ABC conference");
Paper p2 = new Paper("Triangles and Squares: A preschool analysis", "CCCG");
Paper p3 = new Paper("A Nice Paper", "SODA II");
Paper p4 = new Paper("Very Short paper", "IEEE Mini");
Paper p5 = new Paper("A boring paper", "ABC conference");
Paper p6 = new Paper("How to survive first year comp sci", "WALCOMP");
Paper p7 = new Paper("Neural Nets: Say Hi to Our Future Machine Overlords", "CYBORG");
Paper p8 = new Paper("Art of selling your paper", "XYZ conference");
Paper p9 = new Paper("A Funny Paper", "CALLDAM");
Paper p10 = new Paper("Useless graphs and how to draw them", "Graph Drawing");
//add papers to authors
ainsTain.addPaper(p1, pdb);
ainsTain.addPaper(p3, pdb);
ainsTain.addPaper(p4, pdb);
johnDoe.addPaper(p1, pdb);
johnDoe.addPaper(p2, pdb);
peterPan.addPaper(p8, pdb);
peterPan.addPaper(p9, pdb);
robinRoad.addPaper(p5, pdb);
robinRoad.addPaper(p9, pdb);
bugsBunny.addPaper(p6, pdb);
bugsBunny.addPaper(p7, pdb);
bugsBunny.addPaper(p10, pdb);
// Register the authors, except johnDoe
ainsTain.register(pdb);
bugsBunny.register(pdb);
robinRoad.register(pdb);
peterPan.register(pdb);
//Download papers
bugsBunny.downloadPaper(pdb,"A Funny Paper");
bugsBunny.downloadPaper(pdb,"Art of selling your paper");
peterPan.downloadPaper(pdb,"A Nice Paper");
johnDoe.downloadPaper(pdb,"A Nice Paper"); //can't, johnDoe is not registered
ainsTain.downloadPaper(pdb,"A Nice Paper"); //can't, ainsTain is the author of this paper
robinRoad.downloadPaper(pdb,"A Nice Paper");
robinRoad.downloadPaper(pdb,"A Funny Paper");
peterPan.downloadPaper(pdb,"Very Short paper");
peterPan.downloadPaper(pdb,"How to survive first year comp sci");
peterPan.downloadPaper(pdb,"A Nice Paper");
peterPan.downloadPaper(pdb,"Very Short paper");
// Display the downloaded papers
System.out.println("nHere are the downloaded papers: ");
for (Paper p: pdb.getAllDownloadedPapers()){
System.out.println(p);
}
// Display the downloaded papers alphabetically
System.out.println("nHere are the unique downloaded papers alphabetically: ");
for (Paper p: pdb.uniqueDownloads()){
System.out.println(p);
}
// Display the downloaded papers in order of popularity
System.out.println("nHere are the downloaded papers by populariry (BONUS): ");
for (Pair<Integer,Paper> p: pdb.papersByPopularity()){
System.out.println("(" + p.getKey() + " downloads) " + p.getValue());
}
}
}
i am confused how to addPapaer into the PaperDB
