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Searching for a String in an ArrayList of Objects

I have been trying to figure this out for hours and I have had no luck doing so,
I'm trying to iterate over my Arraylist<Booking> which utilizes my Booking class file and trying to understand how I'm able to search it for the matching, case-insensitive term.
this is my current method:
private void searchBookings() {
if (bookings.size() <= 0) {
JOptionPane.showMessageDialog(null, "There are no bookings.", "Search Bookings", 3);
} else {
String searchTerm = JOptionPane.showInputDialog(null, "Please input search term: ", "Search Bookings", 3);
for (int i = 0; i < bookings.size(); i++) {
while (!bookings.get(i).getStudent().getName().equalsIgnoreCase(searchTerm)) {
i++;
if (bookings.get(i).getStudent().getName().equalsIgnoreCase(searchTerm)) {
String output = String.format("%-30s%-18s%-18b$%-11.2f\n", bookings.get(i).getStudent(), bookings.get(i).getLessons(), bookings.get(i).isPurchaseGuitar(), bookings.get(i).calculateCharge());
this.taDisplay.setText(heading + "\n" + output + "\n");
}
}
}
}
JOptionPane.showMessageDialog(null, "There is no booking with that name.", "Search Bookings", 3);
}
I know it's messy but, just trying to make do.
I am trying to retrieve the name of the booking as I am searching by name as well as provide an error message if that names does not exist, to do that I must
use bookings.getStudent().getName() I have had some luck as I can return the value but now I am not able to provide my error message if I do not find it. Any help is appreciated.
package com.mycompany.mavenproject1;
public class Booking {
private Student student;
private int lessons;
private boolean purchaseGuitar;
// CONSTANTS
final int firstDiscountStep = 6;
final int secondDiscountStep = 10;
final int tenPercentDiscount = 10;
final int twentyPercentDiscount = 5;
final double LESSON_COST = 29.95;
final double GUITAR_COST = 199.00;
double LESSON_CHARGE = 0;
final int MINIUMUM_LESSONS = 1;
public Booking() {
}
public Booking(Student student, int lessons, boolean purchaseGuitar) {
this.student = new Student(student.getName(), student.getPhoneNumber(), student.getStudentID());
this.lessons = lessons;
this.purchaseGuitar = purchaseGuitar;
}
public Student getStudent() {
return student;
}
public void setStudent(Student student) {
this.student = student;
}
public int getLessons() {
return lessons;
}
public void setLessons(int lessons) {
this.lessons = lessons;
}
public boolean isPurchaseGuitar() {
return purchaseGuitar;
}
public void setPurchaseGuitar(boolean purchaseGuitar) {
this.purchaseGuitar = purchaseGuitar;
}
public double calculateCharge() {
double tempCharge;
if (lessons < firstDiscountStep) {
LESSON_CHARGE = (lessons * LESSON_COST );
} else if (lessons < secondDiscountStep) {
tempCharge = (lessons * LESSON_COST) / tenPercentDiscount;
LESSON_CHARGE = (lessons * LESSON_COST) - tempCharge;
} else {
tempCharge = (lessons * LESSON_COST) / twentyPercentDiscount;
LESSON_CHARGE = (lessons * LESSON_COST) - tempCharge;
}
if (isPurchaseGuitar()) {
LESSON_CHARGE += GUITAR_COST;
}
return LESSON_CHARGE;
}
#Override
public String toString() {
return student + ","+ lessons + "," + purchaseGuitar +"," + LESSON_COST;
}
}

If I understood you correctly, you are searching for a given student name in your collection of bookings. And if it is present, set a formatted text.
First of all, use a for-each loop, because you don't use the index.
Secondly, return from the for-each loop, when you found your student.
private void searchBookings() {
if (bookings.size() <= 0) {
JOptionPane.showMessageDialog(null, "There are no bookings.", "Search Bookings", 3);
} else {
String searchTerm = JOptionPane.showInputDialog(null, "Please input search term: ", "Search Bookings", 3);
for (final Booking booking : bookings) // for-each
{
if (booking.getStudent().getName().equalsIgnoreCase(searchTerm))
{
String output = booking.getFormattedOutput();
this.taDisplay.setText(heading + "\n" + output + "\n");
return; // break out of the loop and method and don't display dialog message
}
}
}
JOptionPane.showMessageDialog(null, "There is no booking with that name.", "Search Bookings", 3);
}
Then there are multiple other things, which you could improve.
Don't get all the data from a booking just to format it externally. Let the Booking class handle the formatting and return you the string you desire. (move the formatting in a function inside the Booking class)
Instead of recreating a Student you receive in your Booking constructor, make the Student class immutable, and then you can just reuse the object provided.
Try also making the Booking class immutable. You provided some setters, but do you really want to change the student in a booking? Or would you rather create a new booking for the other student?
The calculteCharge method could be stateless. Just get the LESSON_CHARGE value and hold it in a local variable. Your method would also get threading-proof.
Make your constants final and better yet make them members of the class (by adding the static modifier) instead of every member.
Lastly, representing a money amount with a floating (double is better but not good either) number, you will run into funny situations. Try this calculation: 0.1+0.1+0.1+0.1+0.1+0.1+0.1+0.1+0.1+0.1 for example.
One way would be to create a Money class which holds the value in cents as an integer. And when you want to display the amount you can divide it by 100 and format it accordingly. That way, you can also restrict it become negative.
PS: Sometimes we desperately try to find a solution that we don't give ourselves some rest. After a little break, you might recognize the problem. Oh and try debugging with breakpoints. Or this, if you use IntelliJ IDEA (which I would highly recommend, the community edition is free).

You're re-incrementing your counter variable, which is really not going to help. Try the following:
private void searchBookings() {
if (bookings.size() <= 0) {
JOptionPane.showMessageDialog(null, "There are no bookings.", "Search Bookings", 3);
} else {
String searchTerm = JOptionPane.showInputDialog(null, "Please input search term: ", "Search Bookings", 3);
boolean studentFound = false;
for (int i = 0; i < bookings.size(); i++) {
if (bookings.get(i).getStudent().getName().equalsIgnoreCase(searchTerm)) {
String output = String.format("%-30s%-18s%-18b$%-11.2f\n", bookings.get(i).getStudent(),
bookings.get(i).getLessons(), bookings.get(i).isPurchaseGuitar(),
bookings.get(i).calculateCharge());
this.taDisplay.setText(heading + "\n" + output + "\n");
studentFound = true;
break;
}
}
}
if (!studentFound) {
JOptionPane.showMessageDialog(null, "There is no booking with that name.", "Search Bookings", 3);
}
}

why am I getting unreachable statement error in java code. need help to solve this error

Below is the commented line, where I'm getting an unreachable error:
public class HotelRoom{
private int rNo;
private int dRented;
private String rType;
private String occName;
**type of accomodation is checked below**
if(rType=="king"){ this.rType=rType; }
else if(rType=="queen"){ this.rType=rType;}
else if(rType=="suite"){ this.rType=rType;}
else{this.rType = "queen"; } }
**accessor**
public int getRoomNumber(){ return rNo; }
public int getDaysRented(){ return dRented; }
**mutator**
public String getRoomType(){ return rType; }
public String getOccupantName(){return occName; }
**setting the value of occupant based on the conditions**
public boolean setOccupant(String guestName, int days){
if(this.occName!=null){ return false; }
this.occName=guestName; this.dRented = days; return true; }
advance method
public void advanceDay(){
this.dRented = this.dRented - 1;
if(this.dRented <= 0){ this.occName = null; this.dRented = 0;}}
toString method:
public String toString(){String out = "";
if(occName!=null){out = "Rented"; return out;}
else{ out ="Free"; return out;}
Error line -"unreachable error":
return "HotelRoom" + rNo +":" + rType + "-" + out;
}
public static void main (String[] args){
HotelRoom r1 = new HotelRoom(007,"king");
System.out.println(r1);
}
}

The method toString (that I report here reformatted for readable reasons):
public String toString() {
String out = "";
if (occName != null) {
out = "Rented";
return out; // Exit here
} else {
out ="Free";
return out; // or exit here
}
// Never reachable
return "HotelRoom" + rNo +":" + rType + "-" + out;
}
the last row is never reachable because you return from the previous if block and also in the else block, so there is no chance to reach the last line.
I suppose that you like the following behaviour:
public String toString() {
String out = "";
if (occName != null) {
// Just set out variable
out = "Rented";
} else {
// Just set out variable
out ="Free";
}
// Return a complete string using the previous out variable
return "HotelRoom" + rNo +":" + rType + "-" + out;
}
A tip: format always your code so that it is more human readable. A code that is easy to read is also a code that is easy to study to find errors.

How to minimize If else statement on below? or should i use map or switch?

public String identifyCellular(Long phone1, Long phone2, Long phone3) {
String cellular = null;
if (String.valueOf(phone2).trim().replaceAll("\\D", " ").equals("(07'\\d'{8})|(467'\\d'{8})")) {
cellular = String.valueOf(phone2).trim().replaceAll("\\D", " ");
} else if (String.valueOf(phone1).trim().replaceAll("\\D", " ").equals("(07'\\d'{8})|(467'\\d'{8})")) {
cellular = String.valueOf(phone1).trim().replaceAll("\\D", " ");
} else {
cellular = String.valueOf(phone3).trim().replaceAll("\\D", " ");
}
return cellular;
}

It's fine. However, you could trim all 3 variables before the if block, refactor the regex, and return immediately inside the if statement.
Also, to match with regex, use Pattern.compile() and Pattern.matcher() to get the matching group. Then use find() to check if there is any match.
public String identifyCellular(Long phone1, Long phone2, Long phone3) {
String matchedRegex = "(07'\\d'{8})|(467'\\d'{8})";
Pattern r = Pattern.compile(matchedRegex);
String phone1Trimmed = String.valueOf(phone1).trim().replaceAll("\\D", " ");
String phone2Trimmed = String.valueOf(phone2).trim().replaceAll("\\D", " ");
String phone3Trimmed = String.valueOf(phone3).trim().replaceAll("\\D", " ");
if (r.matcher(phone2Trimmed).find()) {
return phone2Trimmed;
} else if (r.matcher(phone1Trimmed).find()) {
return phone1Trimmed;
} else {
return phone3Trimmed;
}
}

When reading your code, I am not sure if the above algorithm is an art for art or a real need to solve the problem. Following your course, I suggest getting rid of if statements
public String identifyCellular(Long... phones) {
String matchedRegex = "(07'\\d'{8})|(467'\\d'{8})";
Pattern pattern = Pattern.compile(matchedRegex);
Optional<Long> first = Arrays.stream(phones)
.filter(filterMatchingNumber(pattern))
.findFirst();
return String.valueOf(first.orElse(giveLastPhone(phones)));
}
private Long giveLastPhone(Long[] phones) {
return phones[phones.length - 1];
}
private Predicate<Long> filterMatchingNumber(Pattern r) {
return phone -> r.matcher(getPhone1Trimmed(phone)).find();
}
private String getPhone1Trimmed(Long phone1) {
return String.valueOf(phone1).trim().replaceAll("\\D", " ");
}
It looks like the trim and replace of a non-digit (\D) to spaces in this case is not needed. I recommend considering to skip it
final String matchedRegex = "(07'\\d'{8})|(467'\\d'{8})";
final Pattern pattern = Pattern.compile(matchedRegex);
public String identifyCellular(Long... phones) {
Optional<Long> first = Arrays.stream(phones)
.filter(filterMatchingNumber(pattern))
.findFirst();
return String.valueOf(first.orElse(giveLastPhone(phones)));
}
private Long giveLastPhone(Long[] phones) {
return phones[phones.length - 1];
}
private Predicate<Long> filterMatchingNumber(Pattern pattern) {
return phone -> pattern.matcher(phone.toString()).find();
}

Helper Method won't work when called from other method, but will from main

I have a helper method that I am calling from another method in the same class. When I test it from main, it works fine. But as soon as I use it in the other class, it doesn't work at all. I cannot figure out what is wrong.
This is the helper method:
private boolean checkStack(Stack<String> stack,String check) {
System.out.println(stack);
System.out.println(check);
Stack<String> jump = new Stack<String>();
int count = 0;
String temp = "";
while (!stack.empty()) {
temp = stack.pop();
if (check == temp) {
count++;
}
jump.push(temp);
}
while (!jump.empty()) {
temp = jump.pop();
stack.push(temp);
}
System.out.println(count);
if (count != 0) {
return true;
} else {
return false;
}
}
I will test it from main like so:
pathSoFar.push("00");
pathSoFar.push("01");
pathSoFar.push("20");
pathSoFar.push("23");
System.out.println(pathSoFar);
String checkfor = "20";
System.out.println(test01.checkStack(pathSoFar,checkfor));
But it wont work when I call it from another method:
for (String n : possibleSpots) {
System.out.println();
String check = n;
if (!checkStack(pathSoFar, n)) {
pathSoFar.push(n);
String x = ""+n.charAt(0);
String y = ""+n.charAt(1);
int nextRow = Integer.parseInt(x);
int nextCol = Integer.parseInt(y);
System.out.println(nextRow + "" + nextCol + " = next move.");
if (findPath(wordToFind, pathSoFar, nextRow, nextCol)) {
return true;
}
} else{}
}
This is the method header if that helps:
private boolean findPath(String wordToFind, Stack<String> pathSoFar, int row, int col) {

possibleSpots can contain either String literals or String objects.
The problem lies in the following line
if (check == temp)
Change it to
if (check.equals(temp))
String matching is done with == which will work only for String literals.
That is the reason why it worked for you in one case and it does not work in another case.
To know the difference check the below link:
What is the difference between == vs equals() in Java?

Infinite while loop in java, not reading in sentinel

I've had this problem throughout multiple programs, but I can't remember how I fixed it last time. In the second while loop in my body, the second sentinel value is never read in for some reason. I've been trying to fix it for a while now, thought I might see if anyone had any clue.
import java.text.DecimalFormat; // imports the decimal format
public class Car {
// Makes three instance variables.
private String make;
private int year;
private double price;
// Makes the an object that formats doubles.
public static DecimalFormat twoDecPl = new DecimalFormat("$0.00");
// Constructor that assigns the instance variables
// to the values that the user made.
public Car(String carMake,int carYear, double carPrice)
{
make = carMake;
year = carYear;
price = carPrice;
}
// Retrieves variable make.
public String getMake()
{
return make;
}
// Retrieves variable year.
public int getYear()
{
return year;
}
// Retrieves variable price.
public double getPrice()
{
return price;
}
// Checks if two objects are equal.
public boolean equals(Car c1, Car c2)
{
boolean b = false;
if(c1.getMake().equals(c2.getMake()) && c1.getPrice() == c2.getPrice() &&
c1.getYear() == c2.getYear())
{
b = true;
return b;
}
else
{
return b;
}
}
// Turns the object into a readable string.
public String toString()
{
return "Description of car:" +
"\n Make : " + make +
"\n Year : " + year +
"\n Price: " + twoDecPl.format(price);
}
}
import java.util.Scanner; // imports a scanner
public class CarSearch {
public static void main(String[] args)
{
// initializes all variables
Scanner scan = new Scanner(System.in);
final int SIZE_ARR = 30;
Car[] carArr = new Car[SIZE_ARR];
final String SENT = "EndDatabase";
String carMake = "";
int carYear = 0;
double carPrice = 0;
int count = 0;
int pos = 0;
final String SECSENT = "EndSearchKeys";
final boolean DEBUG_SW = true;
// Loop that goes through the first list of values.
// It then stores the values in an array, then uses the
// values to make an object.
while(scan.hasNext())
{
if(scan.hasNext())
{
carMake = scan.next();
}
else
{
System.out.println("ERROR - not a String");
System.exit(0);
}
if(carMake.equals(SENT))
{
break;
}
if(scan.hasNextInt())
{
carYear = scan.nextInt();
}
else
{
System.out.println("ERROR - not an int" + count);
System.exit(0);
}
if(scan.hasNextDouble())
{
carPrice = scan.nextDouble();
}
else
{
System.out.println("ERROR - not a double");
System.exit(0);
}
Car car1 = new Car(carMake, carYear, carPrice);
carArr[count] = car1;
count++;
}
// Calls the method debugSwitch to show the debug information.
debugSwitch(carArr, DEBUG_SW, count);
// Calls the method printData to print the database.
printData(carArr, count);
// Loops through the second group of values and stores them in key.
// Then, it searches for a match in the database.
**while(scan.hasNext())**
{
if(scan.hasNext())
{
carMake = scan.next();
}
else
{
System.out.println("ERROR - not a String");
System.exit(0);
}
if(carMake.equals(SECSENT))
{
break;
}
if(scan.hasNextInt())
{
carYear = scan.nextInt();
}
else
{
System.out.println("ERROR - not an int" + count);
System.exit(0);
}
if(scan.hasNextDouble())
{
carPrice = scan.nextDouble();
}
else
{
System.out.println("ERROR - not a double");
System.exit(0);
}
Car key = new Car(carMake, carYear, carPrice);
// Stores the output of seqSearch in pos.
// If the debug switch is on, then it prints these statements.
if(DEBUG_SW == true)
{
System.out.println("Search, make = " + key.getMake());
System.out.println("Search, year = " + key.getYear());
System.out.println("Search, price = " + key.getPrice());
}
System.out.println("key =");
System.out.println(key);
pos = seqSearch(carArr, count, key);
if(pos != -1)
{
System.out.println("This vehicle was found at index = " + pos);
}
else
{
System.out.println("This vehicle was not found in the database.");
}
}
}
// This method prints the database of cars.
private static void printData(Car[] carArr, int count)
{
for(int i = 0; i < count; i++)
{
System.out.println("Description of car:");
System.out.println(carArr[i]);
}
}
// Searches for a match in the database.
private static int seqSearch(Car[] carArr, int count, Car key)
{
for(int i = 0; i < count; i++)
{
boolean b = key.equals(key, carArr[i]);
if(b == true)
{
return i;
}
}
return -1;
}
// Prints debug statements if DEBUG_SW is set to true.
public static void debugSwitch(Car[] carArr, boolean DEBUG_SW, int count)
{
if(DEBUG_SW == true)
{
for(int i = 0; i < count; i++)
{
System.out.println("DB make = " + carArr[i].getMake());
System.out.println("DB year = " + carArr[i].getYear());
System.out.println("DB price = " + carArr[i].getPrice());
}
}
}
}

I think this is your problem, but I might be wrong:
Inside your while loop, you have these calls:
next()
nextInt()
nextDouble()
The problem is that the last call (nextDouble), will not eat the newline. So to fix this issue, you should add an extra nextLine() call at the end of the two loops.
What happens is that the next time you call next(), it will return the newline, instead of the CarMake-thing.