Develop Reference

How toUnit Test ZipOutputStream Or verify the CSVWriter in Java

public void writeEnvToCsv(int customerId, ZipOutputStream zos, List<SummaryDetailsResponse> summaryDetailsResponseList, QueryHelper queryHelper) {
//Headers size = size(No of distinct entities) * 2 + 1
final CsvWriter writer = new CsvWriter(new OutputStreamWriter(zos), new CsvWriterSettings());
final String[] headers = new String[summaryDetailsResponseList.get(0).getEntities().size() * 2 + 1];
String header;
int index = 0, i, k;
headers[index++] = Entities;
for (i = 0; i < summaryDetailsResponseList.get(0).getEntities().size(); i++) {
header = summaryDetailsResponseList.get(0).getEntities().get(i).getEntityType();
if (valueMap.get(header) != null) {
header = valueMap.get(header);
}
headers[index++] = header + " " + Count;
headers[index++] = header + "(s)";
}
writer.writeHeaders(headers);
for (index = 0; index < summaryDetailsResponseList.size(); index++) {
final String[] values = new String[summaryDetailsResponseList.get(index).getEntities().size() * 2 + 1];
i = 0;
k = 0;
values[i++] = summaryDetailsResponseList.get(index).getRecordName();
for (; i <= summaryDetailsResponseList.get(index).getEntities().size() * 2; ) {
values[i++] = String.valueOf(summaryDetailsResponseList.get(index).getEntities().get(k).getEntityData().get(0).getTotal());
try {
StringBuilder strConcat = new StringBuilder();
List<String> hostNames = queryHelper.getHostNames(customerId,
String.valueOf(summaryDetailsResponseList.get(index).getEntities().get(k).getEntityData().get(0).getQuery()));
for (String host : hostNames) {
if (strConcat.toString().equals(""))
strConcat.append(host);
else
strConcat.append(", ").append(host);
}
values[i++] = strConcat.toString();
} catch (Exception e) {
e.printStackTrace();
}
k++;
}
writer.writeRow(CSVUtils.escapeCSVRow(values));
}
writer.flush();
}
Basically I want to write UT to verify this function. Can we verify the CSVWriter that it has written correct data for headers and rows or ZipOutputStream in any way.
I was able to verify the records writer has written if I pass writer to the function instead of creating it inside the function but I don't want to do this.

String Split and operation

public static void clacMethod() {
int result = 0;
// int i;
System.out.println("Enter numbers to calculation");
String input = new Scanner(System.in).nextLine();
String[] inputSplit = new String[input.length()];
int[] output = new int[inputSplit.length];
for (int i = 0; i < inputSplit.length; i++) {
if (input.contains("-")) {
inputSplit = input.split("\\-");
output[i] = Integer.parseInt(inputSplit[i]);
result = output[0];
result -= output[i];
}
if (input.contains("+")) {
inputSplit = input.split("\\+");
output[i] = Integer.parseInt(inputSplit[i]);
result = output[0];
result = result + output[i];
}
}
System.out.println(result);
}
how i have to work
How it have to work "+" and "-" operations on String input
// input should be like: 12+10-4
// output should be: 18

if is not a school exercise use ScripEnginer
public double calc(String input) {
int result;
ScriptEngineManager sem= new ScriptEngineManager();
ScriptEngine engine = sem.getEngineByName("JavaScript");
result = (Double)engine.eval(input)
return result;
}
where input is a String "12+10-4"
and result will be a double 8

How to divide a sentence to words and compare with another string?

I have saved the units in .txt file. These I am getting in an array list. Now I want to check if any of the units present in the string.
List contains :
"units", "kg", "kilogms", "kilo", "literes",
"Liter", "packets", "packet", "gms", "grams", "half kg"
Like, if I have a string - 1kg rice, I want to get numbers from this string and I want to divide this sentence to words and want to compare with each item from array list of units. If it is present I want to save it. So I want to store 1kg and rice separately. string may contain any spaces I want to trim all those spaces and check compare.
Getting text file in an array list.
public class ReadTextFiles {
public static List<String> readItemNamesFile(Context context) {
String sText = null;
List<String> stringList;
try{
InputStream is = context.getResources().openRawResource(R.raw.item_names);
//Use one of the above as per your file existing folder
int size = is.available();
byte[] buffer = new byte[size];
is.read(buffer);
is.close();
sText = new String(buffer, "UTF-8");
String[] sTextArray = sText.replace("\"", "").split(",");
stringList = new ArrayList<String>(Arrays.asList(sTextArray));
System.out.print(stringList);
} catch (IOException ex) {
ex.printStackTrace();
return null;
}
return stringList;
}
}
public void getUnits()
{
List<String> units = new ArrayList<>();
units = ReadTextFiles.readUnitsFile(getActivity());
System.out.print(units.size());
}
Now I want to compare string suppose its "1 kg potato".Then should find potato from the array list. Also it should be case insensitive.

This is the full solution of your requirement as I understood:
String measuring = "\"units\", \"kg\", \"kilogms\", \"kilo\", \"literes\", \"Liter\", \"packets\", \"packet\", \"gms\", \"grams\", \"half kg\"";
String items = "\"Potato\", \"rice\", \"Eggs\", \"Maggi\", \"Dryfruits\", \"Maza\", \"cold drink\", \"sauce\", \"catchup\", \"coconut oil\"";
String matching = "Kg500 Potato";//"Potato 1 kg";
String item = "", measuringUnit = "", quantity = "";
private void findOut() {
String[] sMeasuringArray = measuring.replace("\"", "").split(", ");
ArrayList<String> measuringList = new ArrayList<String>(Arrays.asList(sMeasuringArray));
String[] sItemsArray = items.replace("\"", "").split(", ");
ArrayList<String> itemsList = new ArrayList<String>(Arrays.asList(sItemsArray));
String[] sMatchingArray = matching.split(" ");
matching = matching.toUpperCase();
for (int i = 0; i < measuringList.size(); i++) {
if (matching.contains(measuringList.get(i).toUpperCase())) {
measuringUnit = measuringList.get(i).trim();
break;
}
}
for (int i = 0; i < itemsList.size(); i++) {
if (matching.contains(itemsList.get(i).toUpperCase())) {
item = itemsList.get(i).trim();
break;
}
}
if (matching!= null) {
String[] part = matching.split("(?<=\\D)(?=\\d)|(?<=\\d)(?=\\D)");
for (int k = 0; k < part.length; k++) {
try {
Integer.parseInt(part[k]);
quantity = part[k];
break;
} catch (Exception ex) {
continue;
}
}
}
/*if (sMatchingArray != null) {
if (sMatchingArray.length == 3) {
for (int j = 0; j < sMatchingArray.length; j++) {
if (measuringUnit.trim().equals(sMatchingArray[j].trim())) {
quantity = sMatchingArray[j - 1].trim();
break;
}
}
} else if (sMatchingArray.length == 2) {
String[] part = matching.split("(?<=\\D)(?=\\d)|(?<=\\d)(?=\\D)");
for (int k = 0; k < part.length; k++) {
try {
Integer.parseInt(part[k]);
quantity = part[k];
break;
} catch (Exception ex) {
continue;
}
}
}
}*/
Log.e("Solution: ", "item = " + item + ", measuringUnit = " + measuringUnit + ", quantity = " + quantity);
}

I'm gonna be using algorithmic approach for the answer. So here it goes:
strItem = "1kg rice";
//Run a loop through the list of units and for each unit check this
if (strItem.contains(list.get(index)))
//Do the needful and break

Effective way to read file and parse each line

I have a text file of next format: each line starts with a string which is followed by sequence of numbers. Each line has unknown length (unknown amount of numbers, amount from 0 to 1000).
string_1 3 90 12 0 3
string_2 49 0 12 94 13 8 38 1 95 3
.......
string_n 9 43
Afterwards I must handle each line with handleLine method which accept two arguments: string name and numbers set (see code below).
How to read the file and handle each line with handleLine efficiently?
My workaround:
Read file line by line with java8 streams Files.lines. Is it blocking?
Split each line with regexp
Convert each line into header string and set of numbers
I think it's pretty uneffective due 2nd and 3rd steps. 1st step mean that java convert file bytes to string first and then in 2nd and 3rd steps I convert them back to String/Set<Integer>. Does that influence performance a lot? If yes - how to do better?
public handleFile(String filePath) {
try (Stream<String> stream = Files.lines(Paths.get(filePath))) {
stream.forEach(this::indexLine);
} catch (IOException e) {
e.printStackTrace();
}
}
private void handleLine(String line) {
List<String> resultList = this.parse(line);
String string_i = resultList.remove(0);
Set<Integer> numbers = resultList.stream().map(Integer::valueOf).collect(Collectors.toSet());
handleLine(string_i, numbers); // Here is te final computation which must to be done only with string_i & numbers arguments
}
private List<String> parse(String str) {
List<String> output = new LinkedList<String>();
Matcher match = Pattern.compile("[0-9]+|[a-z]+|[A-Z]+").matcher(str);
while (match.find()) {
output.add(match.group());
}
return output;
}

Regarding your first question, it depends on how you reference the Stream. Streams are inherently lazy, and don't do work if you're not going to use it. For example, the call to Files.lines doesn't actually read the file until you add a terminal operation on the Stream.
From the java doc:
Read all lines from a file as a Stream. Unlike readAllLines, this method does not read all lines into a List, but instead populates lazily as the stream is consumed
The forEach(Consumer<T>) call is a terminal operation, and, at that point, the lines of the file are read one by one and passed to your indexLine method.
Regarding your other comments, you don't really have a question here. What are you trying to measure/minmize? Just because something is multiple steps doesn't inherently make it have poor performance. Even if you created a wizbang oneliner to convert from the File bytes directly to your String & Set, you probably just did the intermediate mapping anonymously, or you've called something that will cause the compiler to do that anyway.

Here is your code to parse line into name and numbers
stream.forEach(line -> {
String[] split = line.split("\\b"); //split with blank seperator
Set<String> numbers = IntStream.range(1, split.length)
.mapToObj(index -> split[index])
.filter(str -> str.matches("\\d+")) //filter numbers
.collect(Collectors.toSet());
handleLine(split[0], numbers);
});
Or another way
Map<Boolean, List<String>> collect = Pattern.compile("\\b")
.splitAsStream(line)
.filter(str -> !str.matches("\\b"))
.collect(Collectors.groupingBy(str -> str.matches("\\d+")));
handleLine(collect.get(Boolean.FALSE).get(0), collect.get(Boolean.TRUE));

I set out to test several ways to go about this problem and measure the performance as best I could under noted conditions. Here's what I tested and how I tested it, along with the accompanying results:
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.Random;
import java.util.Scanner;
import java.util.Set;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
import java.util.stream.Stream;
public class App {
public static void method1(String testFile) {
List<Integer> nums = null;
try (Scanner s = new Scanner(Paths.get(testFile))) {
while (s.hasNext()) {
if (s.hasNextInt())
nums.add(s.nextInt());
else {
nums = new ArrayList<Integer>();
String pre = s.next();
// handleLine( s.next() ... nums ... );
}
}
} catch (IOException e) {
e.printStackTrace();
}
}
public static void method2(String testFile) {
List<Integer> nums = null;
try (BufferedReader in = new BufferedReader(new FileReader(testFile));
Scanner s = new Scanner(in)) {
while (s.hasNext()) {
if (s.hasNextInt())
nums.add(s.nextInt());
else {
nums = new ArrayList<Integer>();
String pre = s.next();
// handleLine( s.next() ... nums ... );
}
}
} catch (IOException e) {
e.printStackTrace();
}
}
public static void method3(String testFile) {
List<Integer> nums = null;
try (BufferedReader br = new BufferedReader(new FileReader(testFile))) {
String line = null;
while ((line = br.readLine()) != null) {
String[] arr = line.split(" ");
nums = new ArrayList<Integer>();
for (int i = 1; i < arr.length; ++i)
nums.add(Integer.valueOf(arr[i]));
// handleLine( ... );
}
} catch (IOException e) {
e.printStackTrace();
}
}
public static void method3_1(String testFile) {
List<Integer> nums = null;
try (BufferedReader br = new BufferedReader(new FileReader(testFile))) {
String line = null;
while ((line = br.readLine()) != null) {
String[] arr = line.split(" ");
nums = new ArrayList<Integer>();
for (int i = 1; i < arr.length; ++i)
nums.add(Integer.parseInt(arr[i]));
// handleLine( ... );
}
} catch (IOException e) {
e.printStackTrace();
}
}
public static void method4(String testFile) {
List<Integer> nums = null;
try {
List<String> lines = Files.readAllLines(Paths.get(testFile));
for (String s : lines) {
String[] arr = s.split(" ");
nums = new ArrayList<Integer>();
for (int i = 1; i < arr.length; ++i)
nums.add(Integer.valueOf(arr[i]));
// handleLine( ... );
}
} catch (IOException e) {
e.printStackTrace();
}
}
public static void method4_1(String testFile) {
List<Integer> nums = null;
try {
List<String> lines = Files.readAllLines(Paths.get(testFile));
for (String s : lines) {
String[] arr = s.split(" ");
nums = new ArrayList<Integer>();
for (int i = 1; i < arr.length; ++i)
nums.add(Integer.parseInt(arr[i]));
// handleLine( ... );
}
} catch (IOException e) {
e.printStackTrace();
}
}
public static void method5(String testFile) {
List<Integer> nums = null;
try (BufferedReader br = Files.newBufferedReader(Paths.get(testFile))) {
List<String> lines = br.lines().collect(Collectors.toList());
for (String s : lines) {
String[] arr = s.split(" ");
nums = new ArrayList<Integer>();
for (int i = 1; i < arr.length; ++i)
nums.add(Integer.valueOf(arr[i]));
// handleLine( ... );
}
} catch (IOException e) {
e.printStackTrace();
}
}
public static void method5_1(String testFile) {
List<Integer> nums = null;
try (BufferedReader br = Files.newBufferedReader(Paths.get(testFile))) {
List<String> lines = br.lines().collect(Collectors.toList());
for (String s : lines) {
String[] arr = s.split(" ");
nums = new ArrayList<Integer>();
for (int i = 1; i < arr.length; ++i)
nums.add(Integer.parseInt(arr[i]));
// handleLine( ... );
}
} catch (IOException e) {
e.printStackTrace();
}
}
public static void method6(String testFile) {
List<Integer> nums = new LinkedList<Integer>();
try (Stream<String> stream = Files.lines(Paths.get(testFile))) {
stream.forEach(line -> {
String[] split = line.split("\\b"); // split with blank seperator
Set<String> numbers = IntStream.range(1, split.length)
.mapToObj(index -> split[index])
.filter(str -> str.matches("\\d+")) // filter numbers
.collect(Collectors.toSet());
numbers.forEach((k) -> nums.add(Integer.parseInt(k)));
// handleLine( ... );
});
} catch (IOException e) {
e.printStackTrace();
}
}
public static void main(String[] args) throws Exception {
args = new String[] { "C:\\Users\\Nick\\Desktop\\test.txt" };
Random r = new Random();
System.out.println("warming up a little...");
for (int i = 0; i < 100000; ++i) {
int x = r.nextInt();
}
long s1 = System.currentTimeMillis();
for (int i = 0; i < 10000; ++i)
method1(args[0]);
long e1 = System.currentTimeMillis();
long s2 = System.currentTimeMillis();
for (int i = 0; i < 10000; ++i)
method2(args[0]);
long e2 = System.currentTimeMillis();
long s3 = System.currentTimeMillis();
for (int i = 0; i < 10000; ++i)
method3(args[0]);
long e3 = System.currentTimeMillis();
long s3_1 = System.currentTimeMillis();
for (int i = 0; i < 10000; ++i)
method3_1(args[0]);
long e3_1 = System.currentTimeMillis();
long s4 = System.currentTimeMillis();
for (int i = 0; i < 10000; ++i)
method4(args[0]);
long e4 = System.currentTimeMillis();
long s4_1 = System.currentTimeMillis();
for (int i = 0; i < 10000; ++i)
method4_1(args[0]);
long e4_1 = System.currentTimeMillis();
long s5 = System.currentTimeMillis();
for (int i = 0; i < 10000; ++i)
method5(args[0]);
long e5 = System.currentTimeMillis();
long s5_1 = System.currentTimeMillis();
for (int i = 0; i < 10000; ++i)
method5_1(args[0]);
long e5_1 = System.currentTimeMillis();
long s6 = System.currentTimeMillis();
for (int i = 0; i < 10000; ++i)
method6(args[0]);
long e6 = System.currentTimeMillis();
System.out.println("method 1 = " + (e1 - s1) + " ms");
System.out.println("method 2 = " + (e2 - s2) + " ms");
System.out.println("method 3 = " + (e3 - s3) + " ms");
System.out.println("method 3_1 = " + (e3_1 - s3_1) + " ms");
System.out.println("method 4 = " + (e4 - s4) + " ms");
System.out.println("method 4_1 = " + (e4_1 - s4_1) + " ms");
System.out.println("method 5 = " + (e5 - s5) + " ms");
System.out.println("method 5_1 = " + (e5_1 - s5_1) + " ms");
System.out.println("method 6 = " + (e6 - s6) + " ms");
}
}
Used with java.version = 1.8.0_101 (Oracle)
x64 OS/processor
Result output:
warming up a little...
method 1 = 1103 ms
method 2 = 872 ms
method 3 = 440 ms
method 3_1 = 418 ms
method 4 = 413 ms
method 4_1 = 376 ms
method 5 = 439 ms
method 5_1 = 384 ms
method 6 = 646 ms
To my understanding, the best approach out of the sample I tested was using Files.readAllLines, s.split(" "), and Integer.parseInt. Those three combinations produced the apparently fastest again, out of the sample I created and tested with At least maybe you'd change to the Integer.parseInt to help somewhat.
Note I used sources to help gain some sought after approaches and applied them to this problem/example. E.g. this blog post, this tutorial, and this awesome dude #Peter-Lawrey. Also, further improvements can always be made!
Also, the test.txt file:
my_name 15 00 29 101 1234
cool_id 11 00 01 10 010101
longer_id_name 1234
dynamic_er 1 2 3 4 5 6 7 8 9 10 11 12 123 1456 15689 555555555
(note: performance may greatly vary depending on file size!)

Java StringTokenizer

I have the following input
(11,C) (5,) (7,AB)
I need to split them into 2 part for each coordinates.
So my intarray should have 11, 5, 7
and my letter array should have C,,AB
But when I try using stringtokenizer,
I only get my intarray should have 11, 5, 7
and my letter array should have C,AB
Is there any way I could get the empty part of (5,)?
Thank you.
Vector<String> points = new Vector<String> ();
String a = "(11,C) (5,) (7,AB)";
StringTokenizer st = new StringTokenizer(a, "(,)");
while(st.hasMoreTokens()) {
points.add(st.nextToken());
}
}
System.out.println(points);

List <Integer> digits = new ArrayList <Integer> ();
List <String> letters = new ArrayList <String> ();
Matcher m = Pattern.compile ("\\((\\d+),(\\w*)\\)").matcher (string);
while (m.find ())
{
digits.add (Integer.valueOf (m.group (1)));
letters.add (m.group (2));
}

Must be like this
String[] values = a.split("\\) \\(");
String[][] result = new String[values.length][2];
for (int i = 0; i < values.length; i++) {
values[i] = values[i].replaceAll("\\(|\\)", "") + " ";
result[i] = values[i].split("\\,");
System.out.println(result[i][0] + " * " + result[i][1]);
}
result will contain coordinate pairs.

public static void main(String[] args) {
String s = "(11,C), (5,) ,(7,AB)";
ArrayList<String> name = new ArrayList<String>();
ArrayList<Integer> number = new ArrayList<Integer>();
int intIndex = 0, stringIndex = 0;
String[] arr = s.split(",");
for (int i = 0; i < arr.length; i++) {
String ss = arr[i].replace("(", "");
ss = ss.replace(")", "");
boolean b = isNumeric(ss);
// System.out.println( Arrays.toString(arr));
if (b) {
int num = Integer.valueOf(ss.trim()).intValue();
number.add(num);
} else
name.add(ss);
}
System.out.println(name);
System.out.println(number);
}
public static boolean isNumeric(String str) {
try {
double d = Double.parseDouble(str);
} catch (NumberFormatException nfe) {
return false;
}
return true;
}
Try this: I have slightly changed the input from "(11,C) (5,) (7,AB)" to "(11,C), (5,) ,(7,AB)" .
Output:
[C, , AB]
[11, 5, 7]

Brutal coding, in raw level:
List<String> points = new ArrayList<String> ();
String source= "(11,C) (5,) (7,AB)";
StringTokenizer deleteLeft = new StringTokenizer(source, "(");
while(deleteLeft.hasMoreTokens()) {
StringTokenizer deleteRight = new StringTokenizer(deleteLeft.nextToken(), ")");
points.add(deleteRight.nextToken());
}
System.out.println(points);
}