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MiniGoogle.java
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MiniGoogle.java
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/*
* MiniGoogle.java
*
* A client program that uses the DatabaseIterator
* and Article classes, along with additional data
* structures, to allow a user to create, modify
* and interact with a google type database.
*
* Author: Maxime Gavronsky ([email protected])
* Date: March 24, 2014
*/
import java.util.*;
public class MiniGoogle {
private static final String [] blackList = { "the", "of", "and", "a", "to", "in", "is",
"you", "that", "it", "he", "was", "for", "on", "are", "as", "with",
"his", "they", "i", "at", "be", "this", "have", "from", "or", "one",
"had", "by", "word", "but", "not", "what", "all", "were", "we", "when",
"your", "can", "said", "there", "use", "an", "each", "which", "she",
"do", "how", "their", "if", "will", "up", "other", "about", "out", "many",
"then", "them", "these", "so", "some", "her", "would", "make", "like",
"him", "into", "time", "has", "look", "two", "more", "write", "go", "see",
"number", "no", "way", "could", "people", "my", "than", "first", "water",
"been", "call", "who", "oil", "its", "now", "find", "long", "down", "day",
"did", "get", "come", "made", "may", "part" };
private char[] charsToRemove = { '.' , ',', ':', ';', '!', '?', '"', '\'', '/', '-', '(', ')', '~' };
private static Article[] getArticleTable(DatabaseIterator db) {
// count how many articles are in the directory
int count = db.getNumArticles();
// now create array
Article[] list = new Article[count];
for(int i = 0; i < count; ++i)
list[i] = db.next();
return list;
}
// take a string, turn it into all lower case, and remove all characters except for
// letters, digits, and whitespace
// (use Character.isWhitespace(..) and similar methods)
private static String preprocess(String s) {
char[] charsToRemove = { '.' , ',', ':', ';', '!', '?', '"', '\'', '/', '-', '(', ')', '~' };
s = s.toLowerCase();
for(int i = 0; i < charsToRemove.length; ++i)
{
String c = Character.toString(charsToRemove[i]);
s = s.replace(c, "");
}
return s;
}
// determine if the string s is a member of the blacklist (given at the bottom of
// this assignment); if so do no process it!
private static boolean blacklisted(String s) {
for(int j = 0; j < blackList.length; ++j){
if(s.equals(blackList[j]))
return true;
}
return false;
}
// take two strings (e.g., the search phrase and the body of an article) and
// preprocess each to remove all but letters, digits, and whitespace, and then
// use the StringTokenizer class to extract each of the terms; create a TermFrequencyTable and
// insert each of the terms which is NOT in the blacklist into the table with its docNum
// (String s being document 0 and String t being document 1);
// finally extract the cosine similarity and return it.
private static double getCosineSimilarity(String s, String t) {
s = preprocess(s);
t = preprocess(t);
StringTokenizer token_s = new StringTokenizer(s);
StringTokenizer token_t = new StringTokenizer(t);
TermFrequencyTable S = new TermFrequencyTable();
while (token_s.hasMoreTokens()) {
String current_0 = token_s.nextToken();
if(!blacklisted(current_0))
S.insert((current_0), 0);
}
while(token_t.hasMoreTokens()){
String current_1 = token_t.nextToken();
if(!blacklisted(current_1))
S.insert((current_1), 1);
}
return S.cosineSimilarity();
}
// Take an ArticleTable and search it for articles most similar to
// the phrase; return a string response that includes the top three
// as shown in the sample session shown below
public static String phraseSearch(String phrase, ArticleTable T) {
MaxHeap F = new MaxHeap();
T.reset();
while(T.hasNext()){
//System.out.println("here");
Article a = T.next();
a.putCS(getCosineSimilarity(phrase, a.getBody()));
F.insert(a);
}
Article max_1 = F.getMax();
Article max_2 = F.getMax();
Article max_3 = F.getMax();
if(max_1.getCS() < 0.001)
return "There are no matching articles.";
else if (max_2.getCS() < 0.001){
String print = "Top Three matches: \nMatch 1 with cosinde similarity of " + max_1.getCS() +": \n" + max_1;
return print;
}
else if (max_3.getCS() < 0.001){
String print = "Top Three matches: \nMatch 1 with cosinde similarity of " + max_1.getCS() +": \n" + max_1 + " \n \n" + "\nMatch 2 with cosinde similarity of " + max_2.getCS() + ": \n" + max_2;
return print;
}
else{
String print = "Top Three matches: \nMatch 1 with cosinde similarity of " + max_1.getCS() +": \n" + max_1 + " \n \n" + "\nMatch 2 with cosinde similarity of " + max_2.getCS() +": \n" + max_2 + " \n \n" + "\nMatch 3 with cosinde similarity of " + max_3.getCS() +": \n" + max_3;
return print;
}
}
private static DatabaseIterator setupDatabase(String path) {
return new DatabaseIterator(path);
}
private static void addArticle(Scanner s, ArticleTable D) {
System.out.println();
System.out.println("Add an article");
System.out.println("==============");
System.out.print("Enter article title: ");
String title = s.nextLine();
System.out.println("You may now enter the body of the article.");
System.out.println("Press return two times when you are done.");
String body = "";
String line = "";
do {
line = s.nextLine();
body += line + "\n";
} while (!line.equals(""));
D.insert(new Article(title, body));
}
private static void removeArticle(Scanner s, ArticleTable D) {
System.out.println();
System.out.println("Remove an article");
System.out.println("=================");
System.out.print("Enter article title: ");
String title = s.nextLine();
D.delete(title);
}
private static void titleSearch(Scanner s, ArticleTable D) {
System.out.println();
System.out.println("Search by article title");
System.out.println("=======================");
System.out.print("Enter article title: ");
String title = s.nextLine();
Article a = D.lookup(title);
if(a != null)
System.out.println(a);
else {
System.out.println("Article not found!");
return;
}
System.out.println("Press return when finished reading.");
s.nextLine();
}
private static void phraseSearcher(Scanner s, ArticleTable D) {
System.out.println();
System.out.println("Search by article title");
System.out.println("=======================");
System.out.print("Enter a search phrase: ");
String title = s.nextLine();
String a = phraseSearch(title, D);
System.out.println(a);
System.out.println("Press return when finished reading.");
s.nextLine();
}
public static void main(String[] args) {
Scanner user = new Scanner(System.in);
String dbPath = "articles/";
DatabaseIterator db = setupDatabase(dbPath);
System.out.println("Read " + db.getNumArticles() +
" articles from disk.");
ArticleTable L = new ArticleTable();
Article[] A = getArticleTable(db);
for(int i = 0; i < A.length; ++i){
L.insert(A[i]);
}
int choice = -1;
do {
System.out.println();
System.out.println("Welcome to Mini-Google!");
System.out.println("=====================");
System.out.println("Make a selection from the " +
"following options:");
System.out.println();
System.out.println("Manipulating the database");
System.out.println("-------------------------");
System.out.println(" 1. add a new article");
System.out.println(" 2. remove an article");
System.out.println(" 3. search by exact article title");
System.out.println(" 4. search by phrase (list of keywords)");
System.out.println();
System.out.print("Enter a selection (1-4, or 0 to quit): ");
choice = user.nextInt();
user.nextLine();
switch (choice) {
case 0:
return;
case 1:
addArticle(user, L);
break;
case 2:
removeArticle(user, L);
break;
case 3:
titleSearch(user, L);
break;
case 4:
phraseSearcher(user, L);
break;
default:
break;
}
choice = -1;
} while (choice < 0 || choice > 4);
}
}