How do I parse negative number in parentheses?

In financial application negative numbers are often represented in parentheses. In this post we will learn how we can parse or convert the negative number in parentheses to produce the represented number value. To parse text / string to a number we can use the java.text.DecimalFormat class.

Beside number in parentheses, in this example we also parse negative number that use the minus sign with the currency symbol like $. Let’s jump to the code snippet below:

package org.kodejava.example.text;

import java.text.DecimalFormat;

public class NegativeNumberParse {
    // Pattern for parsing negative number.
    public static final String PATTERN1 = "#,##0.00;(#,##0.00)";
    public static final String PATTERN2 = "$#,##0.00;-$#,##0.00";

    public static void main(String[] args) throws Exception {
        DecimalFormat df = new DecimalFormat(PATTERN1);

        String number1 = "(1000)";
        String number2 = "(1,500.99)";

        System.out.println("number1 = " + df.parse(number1));
        System.out.println("number2 = " + df.parse(number2));

        df = (DecimalFormat) DecimalFormat.getInstance();
        df.applyPattern(PATTERN2);

        String number3 = "-$1000";
        String number4 = "-$1,500.99";

        System.out.println("number3 = " + df.parse(number3));
        System.out.println("number4 = " + df.parse(number4));
    }
}

And here are the results of our code snippet above:

number1 = -1000
number2 = -1500.99
number3 = -1000
number4 = -1500.99

If you need to display or format negative numbers in parentheses you can take a look at the following example How do I display negative number in parentheses?.

How do I display negative number in parentheses?

The code snippet below show us how to display or format negative number in parentheses. We start by defining the number format, the pattern has two parts separated by a semicolon. In the snippet we use the #,##0.00;(#,##0.00) pattern. The pattern after the semicolon will be use to format negative number.

Next we create an instance of DecimalFormat by calling getInstance() method. We apply the the format pattern for the formatter object by calling the applyPattern() method of the DecimalFormat instance. To format the number we simply call the format() method and pass the number we are going to format for display or print out.

package org.kodejava.example.text;

import java.text.DecimalFormat;

public class NegativeNumberFormat {
    // Pattern for formatting negative number.
    public static final String PATTERN1 = "#,##0.00;(#,##0.00)";
    public static final String PATTERN2 = "$#,##0.00;-$#,##0.00";

    public static void main(String[] args) {
        DecimalFormat df = (DecimalFormat) DecimalFormat.getInstance();
        df.applyPattern(PATTERN1);

        // Format using parentheses
        System.out.println("Positive: " + df.format(125));
        System.out.println("Negative: " + df.format(-125));

        // Format using currency symbol and minus sign
        df.applyPattern(PATTERN2);
        System.out.println("Positive: " + df.format(1000));
        System.out.println("Negative: " + df.format(-1000));
    }
}

The result of the code snippet above is:

Positive: 125.00
Negative: (125.00)
Positive: $1,000.00
Negative: -$1,000.00

If you need to parse negative numbers in parentheses to produce the represented number you can see the following example How do I parse negative number in parentheses?.

How do I convert string to Date in GMT timezone?

The following code snippet convert a string representation of a date into a java.util.Date object and the timezone is set to GMT. To parse the string so that the result is in GMT you must set the TimeZone of the DateFormat object into GMT.

package org.kodejava.example.text;

import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.TimeZone;

public class WithTimezoneStringToDate {
    public static void main(String[] args) {
        //
        // Create a DateFormat and set the timezone to GMT.
        //
        DateFormat df = new SimpleDateFormat("E, dd MMM yyyy HH:mm:ss z");
        df.setTimeZone(TimeZone.getTimeZone("GMT"));

        try {
            //
            // Convert string into Date
            //
            Date today = df.parse("Sun, 12 Feb 2012 00:00:00 GMT");
            System.out.println("Today = " + df.format(today));
        } catch (ParseException e) {
            e.printStackTrace();
        }
    }
}

How do I get pattern string of a SimpleDateFormat?

To format a java.util.Date object we use the SimpleDateFormat class. To get back the string pattern that were used to format the date we can use the toPattern() method of this class.

package org.kodejava.example.text;

import java.text.SimpleDateFormat;
import java.util.Date;

public class SimpleDateFormatToPattern {
    public static void main(String[] args) {
        SimpleDateFormat format = new SimpleDateFormat("EEEE, dd/MM/yyyy");

        //
        // Gets a pattern string describing this date format used by the
        // SimpleDateFormat object.
        //
        String pattern = format.toPattern();

        System.out.println("Pattern = " + pattern);
        System.out.println("Date    = " + format.format(new Date()));
    }
}

The result of the program will be as follow:

Pattern = EEEE, dd/MM/yyyy
Date    = Thursday, 16/06/2011

How do I breaks a paragraph into sentences?

This example show you how to use the BreakIterator.getSentenceInstance() to breaks a paragraphs into sentences that composes the paragraph. To get the BreakIterator instance we call the getSentenceInstance() factory method and passes a locale information.

In the count(BreakIterator bi, String source) method we iterates the the break to extract sentences that composes the paragraph which value is stored in the paragraph variable.

package org.kodejava.example.text;

import java.text.BreakIterator;
import java.util.Locale;

public class BreakSentenceExample {
    public static void main(String[] args) {
        String paragraph =
                "Line boundary analysis determines where a text " +
                "string can be broken when line-wrapping. The " +
                "mechanism correctly handles punctuation and " +
                "hyphenated words. Actual line breaking needs to " +
                "also consider the available line width and is " +
                "handled by higher-level software. ";

        BreakIterator iterator =
                BreakIterator.getSentenceInstance(Locale.US);

        int sentences = count(iterator, paragraph);
        System.out.println("Number of sentences: " + sentences);
    }

    private static int count(BreakIterator bi, String source) {
        int counter = 0;
        bi.setText(source);

        int lastIndex = bi.first();
        while (lastIndex != BreakIterator.DONE) {
            int firstIndex = lastIndex;
            lastIndex = bi.next();

            if (lastIndex != BreakIterator.DONE) {
                String sentence = source.substring(firstIndex, lastIndex);
                System.out.println("sentence = " + sentence);
                counter++;
            }
        }
        return counter;
    }
}

Our program will print the following result on the console screen:

sentence = Line boundary analysis determines where a text string can be broken when line-wrapping. 
sentence = The mechanism correctly handles punctuation and hyphenated words. 
sentence = Actual line breaking needs to also consider the available line width and is handled by higher-level software. 
Number of sentences: 3

How do I breaks a text or sentence into words?

At first it might look simple. We can just split the text using the String.split(), the word is splitted using space. But what if a word ends with questions marks (?) or exclamation marks (!) instead? There might be some other rules that we also need to care.

Using the java.text.BreakIterator makes it much simpler. The class’s getWordInstance() factory method creates a BreakIterator instance for words break. Instantiating a BreakIterator and passing a locale information makes the iterator to breaks the text or sentence according the rule of the locale. This is really helpful when we are working with a complex language such as Japanese or Chinese.

Let us see an example of using the BreakIterator below.

package org.kodejava.example.text;

import java.text.BreakIterator;
import java.util.Locale;

public class BreakIteratorExample {
    public static void main(String[] args) {
        String data = "The quick brown fox jumps over the lazy dog.";
        String search = "dog";

        //
        // Gets an instance of BreakIterator for word break for the
        // given locale. We can instantiate a BreakIterator without
        // specifying the locale. The locale is important when we
        // are working with languages like Japanese or Chinese where
        // the breaks standard may be different compared to English.
        //
        BreakIterator bi = BreakIterator.getWordInstance(Locale.US);

        //
        // Set the text string to be scanned.
        //
        bi.setText(data);

        //
        // Iterates the boundary / breaks
        //
        System.out.println("Iterates each word: ");
        int count = 0;
        int lastIndex = bi.first();
        while (lastIndex != BreakIterator.DONE) {
            int firstIndex = lastIndex;
            lastIndex = bi.next();

            if (lastIndex != BreakIterator.DONE
                    && Character.isLetterOrDigit(
                    data.charAt(firstIndex))) {
                String word = data.substring(firstIndex, lastIndex);
                System.out.println("'" + word + "' found at (" +
                        firstIndex + ", " + lastIndex + ")");

                //
                // Counts how many times the word dog occurs.
                //
                if (word.equalsIgnoreCase(search)) {
                    count++;
                }
            }
        }

        System.out.println("");
        System.out.println("Number of word '" + search +
                "' found = " + count);
    }
}

Here are the program output:

Iterates each word: 
'The' found at (0, 3)
'quick' found at (4, 9)
'brown' found at (10, 15)
'fox' found at (16, 19)
'jumps' found at (20, 25)
'over' found at (26, 30)
'the' found at (31, 34)
'lazy' found at (35, 39)
'dog' found at (40, 43)

Number of word 'dog' found = 1

How do I sort strings data using CollationKey class?

When the strings must be compared multiple times, for example when sorting a list of strings. It’s more efficient to use CollationKey class. Using CollationKey to compare strings is generally faster than using Collator.compare().

You can not create CollationKey directly. Rather, generate them by calling Collator.getCollationKey() method. You can only compare CollationKey generated from the same Collator object.

package org.kodejava.example.text;

import java.text.CollationKey;
import java.text.Collator;
import java.util.Arrays;
import java.util.Collections;

public class CollationKeyExample {
    public static void main(String[] args) {
        String[] countries = {
                "German",
                "United Kingdom",
                "United States",
                "French",
                "Japan",
                "Myanmar",
                "India"
        };

        System.out.println("original:");
        System.out.println(Arrays.toString(countries));

        //
        // Gets Collator object of default locale
        //
        Collator collator = Collator.getInstance();

        //
        // Creates and initializes CollationKey array
        //
        CollationKey[] keys = new CollationKey[countries.length];

        for (int i = 0; i < countries.length; i++) {
            //
            // Generate CollationKey by calling
            // Collator.getCollationKey() method then assign into
            // keys which is an array of CollationKey.
            //
            // The CollationKey for the given String based on the 
            // Collator's collation rules.
            //
            keys[i] = collator.getCollationKey(countries[i]);
        }

        //
        // Sort the keys array
        //
        Collections.sort(Arrays.asList(keys));

        //
        // Print out the sorted array
        //
        System.out.println("sorted result: ");
        StringBuilder sb = new StringBuilder("[");
        for (CollationKey key : keys) {
            sb.append(key.getSourceString()).append(",");
        }
        sb.deleteCharAt(sb.length() - 1).append("]");
        System.out.println(sb.toString());
    }
}

Below is the result of the program:

original:
[German, United Kingdom, United States, French, Japan, Myanmar, India]
sorted result: 
[French,German,India,Japan,Myanmar,United Kingdom,United States]

How do I sort an array of string data using RuleBasedCollator class?

We can use the java.text.Collator class to sort strings in language-specific order. Using the java.text.Collator class makes the string not just sorted by the ASCII code of their characters but it will follow the language natural order of the characters.

If the predefined collation rules do not meet your needs, you can design your own rules and assign them to a RuleBasedCollator object. Customized collation rules are contained in a String object that is passed to the RuleBasedCollator constructor.

package org.kodejava.example.text;

import java.text.Collator;
import java.text.ParseException;
import java.text.RuleBasedCollator;
import java.util.Arrays;
import java.util.Collections;

public class RuleBasedCollatorDemo {
    public static void main(String[] args) {
        String rule1 = ("< a < b < c");
        String rule2 = ("< c < b  < a");
        String rule3 = ("< c < a  < b");

        String words[] = {
                "apple",
                "banana",
                "carrot",
                "apricot",
                "blueberry",
                "cabbage"
        };

        try {
            RuleBasedCollator rb1 = new RuleBasedCollator(rule1);
            RuleBasedCollator rb2 = new RuleBasedCollator(rule2);
            RuleBasedCollator rb3 = new RuleBasedCollator(rule3);

            System.out.println("original: ");
            System.out.println(Arrays.toString(words));

            //
            // Sort based on rule1
            //
            Collections.sort(Arrays.asList(words), rb1);
            System.out.println("nrule: " + rb1.getRules());
            System.out.println(Arrays.toString(words));

            //
            // Sort based on rule2
            //
            Collections.sort(Arrays.asList(words), rb2);
            System.out.println("nrule: " + rb2.getRules());
            System.out.println(Arrays.toString(words));

            //
            // Sort based on rule3
            //
            Collections.sort(Arrays.asList(words), rb3);
            System.out.println("nrule: " + rb3.getRules());
            System.out.println(Arrays.toString(words));
        } catch (ParseException e) {
            e.printStackTrace();
        }
    }
}

Below is the result of sorting strings using a different RuleBasedCollator

original: 
[apple, banana, carrot, apricot, blueberry, cabbage]

rule: < a < b < c
[apple, apricot, banana, blueberry, cabbage, carrot]

rule: < c < b  < a
[cabbage, carrot, banana, blueberry, apple, apricot]

rule: < c < a  < b
[cabbage, carrot, apple, apricot, banana, blueberry]

How do I change the date format symbols for a specified locale?

package org.kodejava.example.text;

import java.text.DateFormatSymbols;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;

public class ChangeDateFormatSymbols {
    public static void main(String[] args) {
        Locale id = new Locale("in", "ID");
        String pattern = "EEEE, dd MMM yyyy";
        Date today = new Date();

        //
        // Gets formatted date specify by the given pattern for
        // Indonesian Locale no changes for default date format
        // is applied here.
        //
        SimpleDateFormat sdf = new SimpleDateFormat(pattern, id);
        String before = sdf.format(today);
        System.out.println("Before format change: " + before);

        //
        // Create a DateFormatSymbols object for Indonesian locale.
        //
        DateFormatSymbols dfs = new DateFormatSymbols(id);

        //
        // Gets String array of default format of weekdays.
        //
        String[] days = dfs.getWeekdays();
        String newDays[] = new String[days.length];
        for (int i = 0; i < days.length; i++) {
            //
            // For each day, apply toUpperCase() method to
            // capitalized it.
            //
            newDays[i] = days[i].toUpperCase();
        }

        //
        // Set String array of weekdays.
        //
        dfs.setWeekdays(newDays);

        //
        // Gets String array of default format of short months.
        //
        String[] shortMonths = dfs.getShortMonths();
        String months[] = new String[shortMonths.length];
        for (int j = 0; j < shortMonths.length; j++) {
            //
            // For each short month, apply toUpperCase() method
            // to capitalized it.
            //
            months[j] = shortMonths[j].toUpperCase();
        }

        //
        // Set String array of short months.
        //
        dfs.setShortMonths(months);

        //
        // Create a SimpleDateFormat object by given pattern and 
        // symbol and then format the date object as String.
        //
        sdf = new SimpleDateFormat(pattern, dfs);
        String after = sdf.format(today);
        System.out.println("After change format : " + after);
    }
}

Here are the output of our program:

Before format change: Jumat, 10 Sep 2010
After change format : JUMAT, 10 SEP 2010

How do I get a formatted date for a specific pattern and locale?

If you want to change formatting styles provided by DateFormat, you can uses SimpleDateFormat class. The SimpleDateFormat class is locale-sensitive.

If you instantiate SimpleDateFormat without a Locale parameter, it will format the date and time according to the default Locale. Both the pattern and the Locale determine the format. For the same pattern, SimpleDateFormat may format a date and time differently if the Locale varies.

package org.kodejava.example.text;

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;

public class SimpleDateFormatChangeLocalePattern {
    public static void main(String[] args) {
        String pattern = "dd-MMM-yyyy";
        Date today = new Date();

        //
        // Gets a formatted date according to the given pattern.
        // Here only the pattern is passed as argument of the
        // SimpleDateFormat constructor, so it will format the
        // date according to the default Locale.
        //
        SimpleDateFormat sdf = new SimpleDateFormat(pattern);
        String local = sdf.format(today);
        System.out.println("Date in default locale: " + local);

        Locale[] locales = {
                Locale.CANADA,
                Locale.FRANCE,
                Locale.GERMANY,
                Locale.US,
                Locale.JAPAN
        };

        for (Locale locale : locales) {
            //
            // Format a date according to the given pattern for each
            // locale.
            //
            sdf = new SimpleDateFormat(pattern, locale);
            String after = sdf.format(today);
            System.out.println(locale.getDisplayCountry() + 
                    " | format: " + after);
        }
    }
}

Here are the variety of output produces when formatting a date in the same date pattern but varies in Locale

Date in default locale: 10-Sep-2010
Canada			 | format: 10-Sep-2010
France			 | format: 10-sept.-2010
Germany			 | format: 10-Sep-2010
United States			 | format: 10-Sep-2010
Japan			 | format: 10-9-2010