Develop Reference

Is there a way to get values of stocks to Java faster?

I made a simple java program that lets you create a stocks scanner/screener. There aren't many features yet, but there is a problem with existing features. I have a class that has a method that creates an array of all stock tickers and returns it. Here it is:
package classes;
import Utility.ArrayModification;
import variables.Ticker;
import java.io.*;
import java.util.Scanner;
public class Market {
public static Ticker[] getAllTickers() throws FileNotFoundException {
Ticker[] allTickers = {};
File currentDirectory = new File(new File("").getAbsolutePath());
String allTickersDirectory = currentDirectory + "\\src\\AllTickers.txt";
Scanner scanner = new Scanner(new File(allTickersDirectory));
while (scanner.hasNextLine()) {
String line = scanner.nextLine();
if(!(line.contains("^"))) {
allTickers = ArrayModification.appendTicker(allTickers, new Ticker(line));
}
}
return allTickers;
}
}
AllTickers.txt is a text file with the names of all tickers in it. I also have another class that stores a datatype, Ticker. Here it is:
package variables;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLConnection;
public class Ticker {
private String savedSymbol;
public Ticker(String symbol) {
savedSymbol = symbol;
}
public String getTicker() {
return savedSymbol;
}
public Ticker setTicker(String symbol) {
savedSymbol = symbol;
return this;
}
public double getPrice() throws IOException {
try {
String stringURL = "https://markets.businessinsider.com/stocks/" + savedSymbol + "-stock";
URL url = new URL(stringURL);
URLConnection urlConn = url.openConnection();
InputStreamReader inStream = new InputStreamReader(urlConn.getInputStream());
BufferedReader buff = new BufferedReader(inStream);
String stringPrice = "-1";
String line = buff.readLine();
while (line != null) {
if (line.contains("price: ")) {
int target = line.indexOf("price: ");
int deci = line.indexOf(".", target);
int start = deci;
int stop = deci;
while (line.charAt(start) != ' ') {
start--;
}
while (line.charAt(stop) != ',') {
stop++;
}
stringPrice = line.substring(start + 1, stop);
break;
}
line = buff.readLine();
}
double price = Double.parseDouble(stringPrice);
return price;
}
catch(Exception e) {
return -1;
}
}
public double getMarketCap() throws IOException {
try {
String stringURL = "https://finviz.com/quote.ashx?t=" + savedSymbol;
URL url = new URL(stringURL);
URLConnection urlConn = url.openConnection();
InputStreamReader inStream = new InputStreamReader(urlConn.getInputStream());
BufferedReader buff = new BufferedReader(inStream);
String stringMarketCap = "-1";
double finalMarketCap = -1;
String line = buff.readLine();
while (line != null) {
if (line.contains(">Market Cap<")) {
int deci = line.indexOf(".");
int start = deci;
int stop = deci;
while (line.charAt(start) != '>') {
start--;
}
while (line.charAt(stop) != '<') {
stop++;
}
stringMarketCap = line.substring(start + 1, stop - 1);
double marketCap = Double.parseDouble(stringMarketCap);
if (line.charAt(stop - 1) == 'B') {
finalMarketCap = marketCap * 1000000000;
} else if (line.charAt(stop - 1) == 'M') {
finalMarketCap = marketCap * 1000000;
}
break;
}
line = buff.readLine();
}
return finalMarketCap;
}
catch(Exception e) {
return -1;
}
}
}
Using all of these, you can create a simple scanner that scans for stocks with a price of, for example, 0 - 15. You can do this by doing this:
import classes.Market;
import variables.Ticker;
import java.io.IOException;
public class Main {
public static void main(String[] args) throws IOException {
Ticker[] allTickers = Market.getAllTickers();
for(int i = 0; i< allTickers.length; i++){
Ticker ticker = allTickers[i];
if(ticker.getPrice() > 0 && ticker.getPrice() < 15) {
System.out.println(ticker.getTicker());
}
}
}
}
It prints out all of the qualifying stocks. However, it is EXTREMELY slow. So slow that it's basically unusable. It is this way because the ticker.getPrice() method has to connect to markets.businessinsider.com, extract the HTML code, find the correct index, and get the price for every single stock out of the 6000 in AllTIckers.txt. Would there be a way to do this faster?

How to serialise and de-serialise an object in Java?

I need to modify class PrimeFactors so that it extends HashMap<Integer,ArrayList> and implements Serializable.
Let x be a number and y be an ArrayList containing the prime factors of x: add all <x,y> pairs to PrimeFactors and serialize the object into a new file.
Then write a method that de-serializes the PrimeFactors object from the file and displays the <x,y> pairs.
Right now, I am completely stuck and unsure how to continue. Any help would be greatly appreciated as I am very unfamiliar with this situation.
Here is my code so far:
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Scanner;
import java.io.Serializable;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.io.ObjectOutputStream;
public class PrimeFactors2 extends HashMap<Integer,ArrayList<Integer>> implements Serializable {
public static void findFactor(int n) {
System.out.print("Factors for the number " + n + " is: ");
for (int i = n; i >= 1; i--) {
if (n % i == 0)
System.out.print(i + " ");
}
}
public static boolean checkForPrime(int number) {
boolean isItPrime = true;
if (number <= 1) {
isItPrime = false;
return isItPrime;
} else {
for (int i = 2; i <= number / 2; i++) {
if ((number % i) == 0) {
isItPrime = false;
break;
}
}
return isItPrime;
}
}
public static void main(String[] args) {
String path = "/Users/benharrington/Desktop/primeOrNot.csv";
String line = "";
try {
BufferedReader br = new BufferedReader(new FileReader(path));
ArrayList<Integer> list = new ArrayList<Integer>();
while ((line = br.readLine()) != null) {
String[] values = line.split(",");
for (String str : values) {
int i = Integer.parseInt(str);
boolean isItPrime = checkForPrime(i);
if (isItPrime)
System.out.println(i + " is Prime");
else
System.out.println(i + " is not Prime");
if (isItPrime == false) {
list.add(i);
}
}
for (int k : list) {
System.out.println(" ");
findFactor(k);
}
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}

What you did in your code is simply reading a file and parsing it.
If you want to serialize and se-derialize an object, it can be done with the following code:
PrimeFactors2 primeFactors2 = // you object creation code here;
// i.e:
// PrimeFactors2 primeFactors2 = new PrimeFactors2();
// primeFactors2.setX1(2);
// primeFactors2.setX2(3);
try {
FileOutputStream fileOut = new FileOutputStream("/tmp/obj.ser");
ObjectOutputStream out = new ObjectOutputStream(fileOut);
out.writeObject(primeFactors2);
out.close();
fileOut.close();
} catch (Exception e) {
e.printStackTrace();
}
Then, in some context (same or another) in the same moment (or whenvever after you created the .ser object), you may de-serialize it with the following code:
try {
FileInputStream fileIn = new FileInputStream("/tmp/obj.ser");
ObjectInputStream in = new ObjectInputStream(fileIn);
PrimeFactors2 primeFactors2 = (PrimeFactors2) in.readObject();
// YAY!!! primeFactors2 is an object with the same values you created before
// i.e: primeFactors.getX1() is 2
// primeFactors.getX2() is 3
in.close();
fileIn.close();
} catch (Exception e) {
e.printStackTrace();
}

Unable to copy txt file over to arraylist and into file

I am attempting to add this large txt file into an array list then sort the data. Then put 15000 lines in various temp files. I am unable to put the data into each file. Here is my code:
package bigfilesorter2;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Scanner;
public class bigfilesorter2 {
public static final int NUM_LINES = 15000;
public static void main(String args[]) throws IOException {
FileReader fileReader = new FileReader("Aesop_Shakespeare_Shelley_Twain.txt");
BufferedReader br = new BufferedReader(fileReader);
ArrayList<String> arraylist = readingfile(br);
//System.out.println(arraylist);
makingfiles(br, arraylist);
}
public static void makingfiles(BufferedReader br, ArrayList<String> arraylist) throws IOException {
int start = 0;
int end = 15000;
for(int i = 0; i < 20; i++) {
File file = new File("/Users/domlanza/desktop/testing/Filee"+i+".txt");
FileWriter fw = new FileWriter(file);
BufferedWriter bw = new BufferedWriter(fw);
for(;start <= end; start++){
bw.write(arraylist.get(start));
bw.newLine();
}
bw.flush();
bw.close();
fw.close();
start = end + 1;
end += 15000;
}
}
public static ArrayList<String> readingfile(BufferedReader br) throws FileNotFoundException, IOException {
//Read in file
Scanner s = new Scanner(new File("Aesop_Shakespeare_Shelley_Twain.txt"));
int count = 0;
ArrayList<String> arraylist = new ArrayList<String>();
while (s.hasNext()) {
count++;
arraylist.add(s.nextLine());
}
//} catch (IOException e) {e.printStackTrace();}
Collections.sort(arraylist);
//System.out.println(arraylist);
return arraylist;
}
}
Any help would be appreciated. the commas were just the file being sorted..................
"it looks like your post is mostly code"

You need to create a list of sublists where each sublist holds 15000 lines. Given below is the complete code:
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
public class BigFileSorter {
public static final int NUM_LINES = 15000;
public static final int NUM_FILES = 20;
public static void main(String args[]) throws IOException {
FileReader fileReader = new FileReader("file.txt");
BufferedReader br = new BufferedReader(fileReader);
ArrayList<ArrayList<String>> list = readingfile(br);
makingfiles(br, list);
}
public static void makingfiles(BufferedReader br, ArrayList<ArrayList<String>> list) throws IOException {
if (list != null) {
for (int i = 0; i < NUM_FILES; i++) {
File file = new File("Filee" + i + ".txt");
FileWriter fw = new FileWriter(file);
ArrayList<String> subList = list.get(i);
for (String str : subList) {
fw.write(str + System.lineSeparator());
}
fw.close();
}
}
}
public static ArrayList<ArrayList<String>> readingfile(BufferedReader br)
throws FileNotFoundException, IOException {
ArrayList<ArrayList<String>> list = new ArrayList<ArrayList<String>>();
ArrayList<String> subList;
String line;
try {
for (int i = 0; i < NUM_FILES; i++) {
subList = new ArrayList<String>();
for (int j = 0; j < NUM_LINES; j++) {
line = br.readLine();
if (line == null) {
break;
}
subList.add(line);
}
Collections.sort(subList);
list.add(subList);
}
} catch (IOException e) {
e.printStackTrace();
} finally {
br.close();
}
return list;
}
}
Feel free to comment in case of any doubt.

Maybe something like this as an inner for loop in your makefiles method.
// outside of the for loops
int start = 0;
int end = 15000;
// inner for loop
for(;start <= end; start++){
bw.write(arraylist.get(start));
bw.newline();
}
// end of outer for loop
start = end + 1;
end += 15000;
So complete method:
public static void makingfiles(BufferedReader br, ArrayList<String> arraylist) throws IOException {
int start = 0;
int end = 15000;
for(int i = 0; i < 20; i++) {
File file = new File("/Users/domlanza/desktop/testing/Filee"+i+".txt");
FileWriter fw = new FileWriter(file);
BufferedWriter bw = new BufferedWriter(fw);
for(;start <= end; start++){
bw.write(arraylist.get(start));
bw.newline();
}
bw.flush();
bw.close();
fw.close()
start = end + 1;
end += 15000;
}
}
Should work for what you asked in the comment, but you still have to change your read method so that it reads all the lines in one arraylist

Java - Read characters from file to ArrayList

I try to create program which can:
1. read characters from file
2. add these characters to ArrayList
3. Check if in line are only characters a,b,c (no other/no spaces)
If 3 is true -
1. compare first & last character in ArrayList, if they are different print "OK"
example file:
abbcb - OK
abbca - NOT OK
a bbc - NOT OK
abdcb - NOT OK
bbbca - OK
At the moment I got:
import java.io.*;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
public class Projekt3
{
public static void main(String[] args) throws IOException
{
List<String> Lista = new ArrayList<String>();
Scanner sc = new Scanner(System.in).useDelimiter("\\s*");
while (!sc.hasNext("z"))
{
char ch = sc.next().charAt(0);
Lista.add(ch);
//System.out.print("[" + ch + "] ");
}
}
}
I have problems with adding character to list. I'll be grateful for help.

import java.io.*;
import java.util.ArrayList;
public class Project3 {
public static void main(String[] args) throws FileNotFoundException, IOException {
BufferedReader reader = new BufferedReader(new FileReader("//home//azeez//Documents//sample")); //replace with your file path
ArrayList<String> wordList = new ArrayList<>();
String line = null;
while ((line = reader.readLine()) != null) {
wordList.add(line);
}
for (String word : wordList) {
if (word.matches("^[abc]+$")) {
if (word.charAt(0) == word.charAt(word.length() - 1)) {
System.out.print(word + "-NOT OK" + " ");
} else {
System.out.print(word + "-OK" + " ");
}
}
}
}
}

i think this is good start for you:
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
public class Project3 {
public static void main(String[] args) {
String path = "/Users/David/sandbox/java/test.txt";
try (BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(path)))) {
String currentLine = null;
// Array list for your words
List<String> arrayList = new ArrayList<>();
while ((currentLine = br.readLine()) != null) {
// only a, b and c
if (currentLine.contains("a") && currentLine.contains("b") && currentLine.contains("c")) {
// start character equal end character
if (currentLine.substring(0, 1)
.equals(currentLine.substring(currentLine.length()-1, currentLine.length()))) {
arrayList.add(currentLine);
System.out.println(currentLine);
}
}
}
} catch (Throwable e) {
System.err.println("error on read file " + e.getMessage());
e.printStackTrace();
}
}
}

read from csv file in java

I have a huge CSV file.I have to read it and store in a database using java.below code only read about 2000 rows from that file and store it into database.why? note the below calculation is to change the seconds to minutes with approximation.dont think a lot about that
import com.opencsv.CSVReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
public class ReadCSV {
public static void main(String[] args) throws SQLException{
MainController mc = new MainController();
boolean status=false;
String csvFile = "C:/Users/Thanushiya/Desktop/mobios/internship/csvfile/csvfile/Master.csv";
CSVReader reader = null;
List myList = new ArrayList();
String[] row = null;
int duration_m = 0;
try {
reader = new CSVReader (new FileReader(csvFile), ',', '\'', 17);
myList = reader.readAll();
int i=0;
for (Object object : myList) {
row = (String[]) object;
float duration_float = Float.parseFloat(row[12]) / 60 ;
float duration_mod = duration_float % 1 ;
if(Integer.parseInt(row[12]) <= 60){
duration_m = 1;
}
else{
if(duration_mod == 0 ){
duration_m = (int) duration_float;
}
else{
duration_m = ((int) duration_float) + 1;
}
}
String query = "INSERT INTO master(msisdn,serv,start,end,ringwithdurartion,duration_s,status,cid,duration_m) values ('"+row[0]+"','"+row[4]+"','"+row[8]+"','"+row[10]+"','"+row[11]+"','"+row[12]+"','"+row[13]+"','"+row[15]+"','"+duration_m+"')";
status=mc.insertData(query);
}//end for
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
System.out.println("Done");
}
}

With readAll() you're loading (or at least trying to load) the entire file into memory at once. That will severely limit the number of lines you can read before running out of memory. As indicated on the OpenCSV homepage, there's also an iterator that reads line per line:
CSVReader reader = new CSVReader(new FileReader("C:/Users/Thanushiya/Desktop/mobios/internship/csvfile/csvfile/Master.csv"), ',', '\'', 17);
String [] nextLine;
while ((nextLine = reader.readNext()) != null) {
// put the code from your for loop here
}