StringUtil.java

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package com.buglabs.util;

import java.util.ArrayList;
import java.util.List;

/**
 * An assortment of string utilities to close the gap to J2SE 1.4
 * 
 * @author kgilmer
 * 
 */
public class StringUtil {

	/**
	 * custom string splitting function as CDC/Foundation does not include
	 * String.split();
	 * 
	 * @param s
	 *            Input String
	 * @param seperator
	 * @return
	 */
	public static String[] split(String s, String seperator) {
		if (s == null || seperator == null || s.length() == 0 || seperator.length() == 0) {
			return (new String[0]);
		}

		List tokens = new ArrayList();
		String token;
		int index_a = 0;
		int index_b = 0;

		while (true) {
			index_b = s.indexOf(seperator, index_a);
			if (index_b == -1) {
				token = s.substring(index_a);

				if (token.length() > 0) {
					tokens.add(token);
				}

				break;
			}
			token = s.substring(index_a, index_b);
			
			if (token.length() >= 0) {
				tokens.add(token);
			}
			index_a = index_b + seperator.length();
		}
		String[] str_array = new String[tokens.size()];
		for (int i = 0; i < str_array.length; i++) {
			str_array[i] = (String) (tokens.get(i));
		}
		return str_array;
	}

	/**
	 * Replaces a {@link String} within a {@link String}
	 * 
	 * @param target
	 *            {@link String} where replacement needs to be done
	 * @param from
	 *            {@link String} to replace from
	 * @param to
	 *            {@link String} to replace to
	 * @return
	 */
	public static String replace(String target, String from, String to) {
		int start = target.indexOf(from);
		if (start == -1)
			return target;
		int lf = from.length();
		char[] targetChars = target.toCharArray();
		StringBuffer buffer = new StringBuffer();
		int copyFrom = 0;
		while (start != -1) {
			buffer.append(targetChars, copyFrom, start - copyFrom);
			buffer.append(to);
			copyFrom = start + lf;
			start = target.indexOf(from, copyFrom);
		}
		buffer.append(targetChars, copyFrom, targetChars.length - copyFrom);
		return buffer.toString();
	}

	/**
	 * Joins elements in {@link List} with a delimiter {@link String}
	 * 
	 * @param list
	 * @param delimiter
	 * @return
	 */
	public static String join(List list, String delimiter) {
		String out = "";
		for (int i = 0; i < list.size(); i++) {
			out += list.get(i);
			if (i < list.size() - 1) {
				out += delimiter;
			}
		}
		return out;
	}

	/**
	 * Remove extra white spaces
	 * 
	 * @param source
	 * @return
	 */
	public static String squeeze(String source) {
		char[] arr = source.toCharArray();
		String out = "";
		char prev = ' ';
		for (int i = 0; i < arr.length; i++) {
			if (!(prev == ' ' && arr[i] == ' ')) {
				out += arr[i];
			}
			prev = arr[i];
		}
		return out;
	}
}