Trim leading character that matches a given predicate

Write a function that takes a string and predicate as input and trim all the characters that matches to given predicate.

 

Signature

public static String trimLeading(final String str, final Predicate<Character> predicate)

 

Find the below working application.

 

TrimLeadCharacterDemo.java

package com.sample.app.strings;

import java.util.function.Predicate;

public class TrimLeadCharacterDemo {

	public static boolean isEmpty(CharSequence str) {
		return str == null || str.length() == 0;
	}

	public static String trimLeading(final String str, final Predicate<Character> predicate) {
		if (isEmpty(str)) {
			return str;
		}

		int counter = 0;
		while (counter < str.length()) {
			if (predicate.test(str.charAt(counter))) {
				counter++;
				continue;
			}
			return str.substring(counter);
		}

		return str.substring(counter);
	}

	public static void main(String[] args) {

		String str1 = trimLeading("abcd", character -> character == 'c');
		String str2 = trimLeading("ccbd", character -> character == 'c');
		String str3 = trimLeading("ccccc", character -> character == 'c');

		System.out.println("str1 : " + str1);
		System.out.println("str2 : " + str2);
		System.out.println("str3 : " + str3);

		str1.trim();

	}

}

 

Output

str1 : abcd
str2 : bd
str3 :

 

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