We Keep Coding

Java string manipulation for validity

Say for instance I have this string:
"His name is Justin Hoffman"
and need to check if it is a valid name:
In order for this to return true I need to make sure I have "His name" before "is" and I need "Justin Hoffman" after the "is" how can I check to see if I have the correct substring before "is" and the correct one after "is"

String sentence = "His name is Justin Hoffman";
String[] splitSentence = sentence.split(" is ");
String first = splitSentence[0]; // His name
String second = splitSentence[1]; // Justin Hoffman
boolean isTrue = (first.equals("His name") && second.equals("Justin Hoffman"));

String input = "His name is Justin Hoffman";
String requiredFirstName = "His name";
String requiredLastName = "Justin Hoffman";
String delimiter = " is ";
// Example 1
if (input.equals(requiredFirstName + delimiter + requiredLastName))
{
System.out.println("The input is OK");
}
// Example 2
int posi = input.indexOf(delimiter);
if (posi > 0) // found
{
String leftPart = input.substring(0, posi);
String rightpart = input.substring(posi + delimiter.length());
if (requiredFirstName.equals(leftPart) && requiredLastName.equals(rightpart))
{
System.out.println("The input is OK");
}
}
// Example 3
String[] parts = input.split(delimiter);
if (requiredFirstName.equals(parts[0]) && requiredLastName.equals(parts[1]))
{
System.out.println("The input is OK");
}
The second example is possibly the fastest one because it does not produce temporary strings. The third example is the slowest one. Be careful with special character in the delimiter because the split() function interprets the argument as a regular expression.

How do I stop regex after finding "Message: "?

I'm splitting the body of a JSON message with the regex ":|\n" and storing the values into an array. I would like to get assistance with stopping my regex expression from splitting the message once it finds "Message: ".
In the JSON body, each section is separated by a new line, so the body looks similar to this:
{"body": "Name: Alfred Alonso\nCompany: null\nEmail: 123#abc.com\nPhone Number: 123-456-9999\nProject Type: Existing\nContact by: Email\nTime Frame: within 1 month\nMessage: Hello,\nThis is my message.\nThank You,\nJohn Doe"}
The code below works perfectly when the user doesn't create a new line within the message, so the entire message gets stored as one array value.
Thank you to anyone that can help me fix this!
String[] messArr = body.split(":|\n");
for (int i = 0; i < messArr.length; i++)
messArr[i] = messArr[i].trim();
if ("xxx".equals(eventSourceARN)) {
name = messArr[1];
String[] temp;
String delimiter = " ";
temp = name.split(delimiter);
name = temp[0];
String lastName = temp[1];
company = messArr[3];
email = messArr[5];
phoneNumber = messArr[7];
projectType = messArr[9];
contactBy = messArr[11];
timeFrame = messArr[13];
message = messArr[15];
I would like
messArr[14] = "Message"
messArr[15] = "Hello, This is my message. Thank you, John Doe"
This is what I get
[..., Message, Hello,, This is my message., Thank You, John Doe].
messArr[14] = "Message"
messArr[15] = "Hello,"
messArr[16] = "This is my message."
messArr[17] = "Thank You,"
messArr[18] = "John Doe"

Instead of using split, you can use a find loop, e.g.
Pattern p = Pattern.compile("([^:\\v]+): |((?<=Message: )(?s:.*)|(?<!$).*)\\R?");
List<String> result = new ArrayList<>();
for (Matcher m = p.matcher(input); m.find(); )
result.add(m.start(1) != -1 ? m.group(1) : m.group(2));
Test
String input = "Name: Alfred Alonso\n" +
"Company: null\n" +
"Email: 123#abc.com\n" +
"Phone Number: 123-456-9999\n" +
"Project Type: Existing\n" +
"Contact by: Email\n" +
"Time Frame: within 1 month\n" +
"Message: Hello,\n" +
"This is my message.\n" +
"Thank You,\n" +
"John Doe";
Pattern p = Pattern.compile("([^:\\v]+): |((?<=Message: )(?s:.*)|(?!$).*)\\R?");
List<String> result = new ArrayList<>();
for (Matcher m = p.matcher(input); m.find(); )
result.add(m.start(1) != -1 ? m.group(1) : m.group(2));
for (int i = 0; i < result.size(); i++)
System.out.println("result[" + i + "]: " + result.get(i));
Output
result[0]: Name
result[1]: Alfred Alonso
result[2]: Company
result[3]: null
result[4]: Email
result[5]: 123#abc.com
result[6]: Phone Number
result[7]: 123-456-9999
result[8]: Project Type
result[9]: Existing
result[10]: Contact by
result[11]: Email
result[12]: Time Frame
result[13]: within 1 month
result[14]: Message
result[15]: Hello,
This is my message.
Thank You,
John Doe
Explanation
Match one of:
( Start capture #1
[^:\v]+ Match one or more characters that are not a : or a linebreak
) End capture #1
: Match, but don't capture, a : and a space (which SO is hiding here)
| or:
( Start capture #2
Match one of:
(?<=Message: )(?s:.*) Rest of input, i.e. all text including linebreaks, if the text is immediately preceded by "Message: "
| or:
(?!$) Don't match if we're already at end-of-input
.* Match 0 or more characters up to end-of-line, excluding the EOL
) End capture #2
\\R? Match, but don't capture, an optional linebreak. This doesn't apply to Message text, and is optional in case there is no Message text and no linebreak after last value

If you want to, you could do exactly what you are doing and then put things together later. As you are trimming, notice where it says Message, then know that the Message is in the next slot and beyond. Then put it back together.
int messagePosition = -1;
for (int i = 0; i < messArr.length; i++){
messArr[i] = messArr[i].trim();
if (i>0 && messArr[i-1].equals("Message")){
messagePosition =i;
}
}
if (messagePosition > -1){
for (int i=messagePosition+1; i <messArr.length; i++){
messArr[messagePosition]=messArr[messagePosition]+" "+messArr[i];
}
}
One downside is that because arrays are fixed size, you need to act as if there is nothing beyond the messagePosition. So any calculations with length will be misleading. If for some reason you are worried you will look in the slots beyond, you could add messArr[i]=""; to the second for loop after the concatenation step.

Using regex and android for categorizing different fields

I am currently trying do a business name card scanner app. The idea here is to take a picture of a name card and it would extract the text and categorize the text into different EditText.
I have already completed the OCR part which extract out all the text from a name card image.
What I am missing now is to make a regex method which can take this entire text extracted from OCR and categorize the name, email address, phone number into their respective fields in EditText.
Through some googling I have already found the regex formulas below:
private static final String EMAIL_PATTERN =
"[a-zA-Z0-9\\+\\.\\_\\%\\-\\+]{1,256}" +
"\\#" +
"[a-zA-Z0-9][a-zA-Z0-9\\-]{0,64}" +
"(" +
"\\." +
"[a-zA-Z0-9][a-zA-Z0-9\\-]{0,25}" +
")+";
private static final String PHONE_PATTERN =
"^[89]\\d{7}$";
private static final String NAME_PATTERN =
"/^[a-z ,.'-]+$/i";
Currently I am just able to extract out the email address using the below method:
public String EmailValidator(String email) {
Pattern pattern = Pattern.compile(EMAIL_PATTERN);
Matcher matcher = pattern.matcher(email);
if (matcher.find()) {
return email.substring(matcher.start(), matcher.end());
} else {
// TODO handle condition when input doesn't have an email address
}
return email;
}
I am unsure of how to edit the ^above method^ to include using all the 3 regex patterns at once and display them to different EditText fields like (name, email address, phone number).
--------------------------------------------EDIT-------------------------------------------------
After using #Styx answer,
it has a problem with the parameter whereby how I used to pass the text "textToUse" to the method as shown below:
I have also tried passing the text into all three parameters. But since the method is void, it cannot be done. Or if I change the method to a String instead of void, it would require a return value.

Try this code. The function takes in the recognize text and split it using break line symbol. Then run a loop and determine the type of content by running a pattern check. Whenever a pattern is determined then the loop will go into next iteration using continue keyword. This piece of code also able to handle situation where 1 or more email and phone number appear on a single business card. Hope it helps. Cheers!
public void validator(String recognizeText) {
Pattern emailPattern = Pattern.compile(EMAIL_PATTERN);
Pattern phonePattern = Pattern.compile(PHONE_PATTERN);
Pattern namePattern = Pattern.compile(NAME_PATTERN);
String possibleEmail, possiblePhone, possibleName;
possibleEmail = possiblePhone = possibleName = "";
Matcher matcher;
String[] words = recognizeText.split("\\r?\\n");
for (String word : words) {
//try to determine is the word an email by running a pattern check.
matcher = emailPattern.matcher(word);
if (matcher.find()) {
possibleEmail = possibleEmail + word + " ";
continue;
}
//try to determine is the word a phone number by running a pattern check.
matcher = phonePattern.matcher(word);
if (matcher.find()) {
possiblePhone = possiblePhone + word + " ";
continue;
}
//try to determine is the word a name by running a pattern check.
matcher = namePattern.matcher(word);
if (matcher.find()) {
possibleName = possibleName + word + " ";
continue;
}
}
//after the loop then only set possibleEmail, possiblePhone, and possibleName into
//their respective EditText here.
}

Best way to split a string containing question marks and equals

Having an issue where I have a java string:
String aString="name==p==?header=hello?aname=?????lname=lastname";
I need to split on question marks followed by equals.
The result should be key/value pairs:
name = "=p=="
header = "hello"
aname = "????"
lname = "lastname"
The problem is aname and lname become:
name = ""
lname = "????lname=lastname"
My code simply splits by doing aString.split("\\?",2)
which will return 2 strings.One contains a key/value pair and the second string contains
the rest of the string. If I find a question mark in the string, I recurse on the second string to further break it down.
private String split(String aString)
{
System.out.println("Split: " + aString);
String[] vals = aString.split("\\?",2);
System.out.println(" - Found: " + vals.length);
for ( int c = 0;c<vals.length;c++ )
{
System.out.println(" - "+ c + "| String: [" + vals[c] + "]" );
if(vals[c].indexOf("?") > 0 )
{
split(vals[c]);
}
}
return ""; // For now return nothing...
}
Any ideas how I could allow a name of ?
Disclaimer: Yes , My Regex skills are very low, so I don't know if this could be done via a regex expression.

You can let regex do all the heavy lifting, first splitting your string up into pairs:
String[] pairs = aString.split("\\?(?!\\?)");
That regex means "a ? not followed by a ?", which gives:
[name==p==, header=hello, aname=????, lname=lastname]
To then also split the results into name/value, split only the first "=":
String[] split = pair.split("=", 2); // max 2 parts
Putting it all together:
String aString = "name==p==?header=hello?aname=?????lname=lastname";
for (String pair : aString.split("\\?(?!\\?)")) {
String[] split = pair.split("=", 2);
System.out.println(split[0] + " is " + split[1]);
}
Output:
name is =p==
header is hello
aname is ????
lname is lastname

You can try like this
String[] vals = "Hello??Man?HowAreYou????".split("\\?+");
System.out.println(vals[0]+vals[1]+vals[2]);
OUTPUT
HelloManHowAreYou
But as aname=????? you want to get you can replace the
????? Five Question Marks with Other Symbol and replace back to ????? after split
String processed="Hello????Good? ? ....???".replace("????","*");
OUTPUT
Hello*Good? ? ....???
And than use split for ?

Here the code, you are looking .
Implemented using the Split and HashMap.
Tested and Executed.
import java.util.HashMap;
import java.util.Map;
public class Sample {
public static void main(String[] args) {
// TODO Auto-generated method stub
// String[] vals = "Hello??Man?HowAreYou????".split("\\?+");
// System.out.println(vals[0]+vals[1]+vals[2]);
String query="name==p==?header=hello?aname=?????lname=lastname";
String[] params = query.split("\\?");
Map<String, String> map = new HashMap<String, String>();
for (String param : params)
{
String name = param.split("=")[0];
String value = param.substring(name.length(),param.length());
map.put(name, value);
System.out.println(name);
if(name.equals("")){
value+="?";
}
System.out.println(value.replaceAll(" ", ""));
}
}
}

I assume you are parsing URLs. The correct way would be to encode all special characters like ?, & and = which are values or names.
Better Solution: Encoding characters:
String name = "=p==";
String aname = "aname=????";
String lname = "lastname";
String url = "name=" + URLEncoder.encode(name, "UTF-8") +
"?aname=" + URLEncoder.encode(aname, "UTF-8") +
"?lname=" + URLEncoder.encode(lname, "UTF-8");
After that you have something like this:
name==p==?aname=?????lname=lastname
This can be splitted and decoded easily.
Other Solution: Bad input parsing:
If you insist, this works also. You can use a regex:
Pattern pattern = Pattern.compile("(\\w+?)=(\\S+?\\?+)");
Matcher m = pattern.matcher(query + "?");
while (m.find()) {
String key = m.group(1);
String value = m.group(2);
value = value.substring(0, value.length() - 1);
System.out.println(key + " = " +value);
}

Error reading data from textfile

I have an application that suppose to read data from the text file with student details (student.txt), such that I have a studentNo, StudentName, Marks etc. . .
Here is a sample of the data that's in the textfile :
20405587 "ZULU,B M" 65 67
20407388 "JUGGERNATH,N" 66 63
20408427 "KHATHI,P X" 60 60
20409821 "SINGH,T" 62 59
20410422 "NKOMO,N N" 58 60
I'm using a scanner to read from the file, here is my code so far. . .it gives me an error
try
{
BufferedReader br = new BufferedReader(new FileReader("student.txt"));
String line = br.readLine();
while (line!=null)
{
Scanner scan = new Scanner(line);
scan.useDelimiter(" ");
String dummystudent=scan.next();
int studentNo= Integer.parseInt(dummystudent);
String dummyname1 = scan.next();
String dummyname2 = scan.next();
String studentName = dummyname1+dummyname2;
String dummytest1 = scan.next();
int test1= Integer.parseInt(dummytest1);
String dummytest2 = scan.next();
int test2= Integer.parseInt(dummytest2);
tad1.setText(tad1.getText()+"Student Number: " + studentNo + '\n' + "Student Name :" + studentName );
line = br.readLine();
}
br.close();
}
catch(Exception b)
{
JOptionPane.showMessageDialog(null,b.getMessage());
}

You set the delimiter to a single space. This is the problem. next will return an empty string a few times because those lines of yours has more than one consecutive spaces.
Instead you want to say one or more spaces:
sc.useDelimiter(" +");
It's still not 100% since "ZULU,B M" has a space in the middle and "JUGGERNATH,N" doesn't, but I'll leave that to you to figure out. Maybe:
sc.useDelimiter("\"");
somewhere in the middle there.
The + has to do with regular expressions, see this for more in general and this for more Java-specific.

Your parsing seems to be overkill.
Consider using Scanner to read the line and use StringUtils.split() to parse the line.
Here is some code:
public static void main(String[] args)
{
int index = 1; // Just for printing.
for (String current : input)
{
String[] split1; // result: number, name, numbers
String[] split2;
String studentName1;
String studentName2;
String studentNumber;
String testScore1;
String testScore2;
split1 = StringUtils.split(current, '"');
studentNumber = StringUtils.trim(split1[0]);
split2 = StringUtils.split(split1[1], ',');
studentName1 = StringUtils.trim(split2[0]);
studentName2 = StringUtils.trim(split2[1]);
split2 = StringUtils.split(split1[2]); // default seperator is whitespace.
testScore1 = StringUtils.trim(split2[0]);
testScore2 = StringUtils.trim(split2[1]);
System.out.println(
index + ":" +
" Number: " + ">" + studentNumber + "" + studentName1 + "" + studentName2 + "" + testScore1 + "" + testScore2 + "
Note: StringUtils is from Apache Commons Lang

Easiest way to end would to be go line by line.
Pattern filePatten = Pattern.compile("\\s*(\\d+)\\s+(\"[^\"]+\")\\s+(\\d+)\\s+(\\d+)\\s*");
while (scanner.hasNextLine()) {
String line = scanner.nextLine();
Matcher matcher = filePattern.matcher(line);
if (matcher.matches()) {
String id = matcher.group(1);
String name = matcher.group(2);
//etc
} else {
//Warn : Fragile Regex
}
}
Each group in the regex captures a part of the line. The second group captures the name with quotes. You might want to remove it.

You should be using the delimiter "? +"?, the delimiter is a regex, and your string has multiple spaces to separate fields, you also need to take into account quotes around string fields. I'm yet to workout how to solve string fields with spaces.
http://docs.oracle.com/javase/1.5.0/docs/api/java/util/Scanner.html#useDelimiter(java.lang.String)
Using Regex you should be able to do it using the below regex string, and select the subgroups 1-4, through a Matcher
([0-9]{8}) +"([A-Z, ]+)" +([0-9]{2}) +([0-9]{2})