// // Getdown - application installer, patcher and launcher // Copyright (C) 2004-2018 Getdown authors // https://github.com/threerings/getdown/blob/master/LICENSE package com.threerings.getdown.util; import java.util.StringTokenizer; public class StringUtil { /** * @return true if the specified string could be a valid URL (contains no illegal characters) */ public static boolean couldBeValidUrl (String url) { return url.matches("[A-Za-z0-9\\-\\._~:/\\?#\\[\\]@!$&'\\(\\)\\*\\+,;=%]+"); } /** * @return true if the string is null or consists only of whitespace, false otherwise. */ public static boolean isBlank (String value) { for (int ii = 0, ll = (value == null) ? 0 : value.length(); ii < ll; ii++) { if (!Character.isWhitespace(value.charAt(ii))) { return false; } } return true; } /** * Parses an array of integers from it's string representation. The array should be represented * as a bare list of numbers separated by commas, for example: * *
25, 17, 21, 99* * Any inability to parse the int array will result in the function returning null. */ public static int[] parseIntArray (String source) { StringTokenizer tok = new StringTokenizer(source, ","); int[] vals = new int[tok.countTokens()]; for (int i = 0; tok.hasMoreTokens(); i++) { try { // trim the whitespace from the token vals[i] = Integer.parseInt(tok.nextToken().trim()); } catch (NumberFormatException nfe) { return null; } } return vals; } /** * Parses an array of strings from a single string. The array should be represented as a bare * list of strings separated by commas, for example: * *
mary, had, a, little, lamb, and, an, escaped, comma,,* * If a comma is desired in one of the strings, it should be escaped by putting two commas in a * row. Any inability to parse the string array will result in the function returning null. */ public static String[] parseStringArray (String source) { return parseStringArray(source, false); } /** * Like {@link #parseStringArray(String)} but can be instructed to invoke {@link String#intern} * on the strings being parsed into the array. */ public static String[] parseStringArray (String source, boolean intern) { int tcount = 0, tpos = -1, tstart = 0; // empty strings result in zero length arrays if (source.length() == 0) { return new String[0]; } // sort out escaped commas source = source.replace(",,", "%COMMA%"); // count up the number of tokens while ((tpos = source.indexOf(",", tpos+1)) != -1) { tcount++; } String[] tokens = new String[tcount+1]; tpos = -1; tcount = 0; // do the split while ((tpos = source.indexOf(",", tpos+1)) != -1) { tokens[tcount] = source.substring(tstart, tpos); tokens[tcount] = tokens[tcount].trim().replace("%COMMA%", ","); if (intern) { tokens[tcount] = tokens[tcount].intern(); } tstart = tpos+1; tcount++; } // grab the last token tokens[tcount] = source.substring(tstart); tokens[tcount] = tokens[tcount].trim().replace("%COMMA%", ","); return tokens; } /** * @return the supplied string if it is non-null, "" if it is null. */ public static String deNull (String value) { return (value == null) ? "" : value; } /** * Generates a string from the supplied bytes that is the HEX encoded representation of those * bytes. Returns the empty string for a
null
or empty byte array.
*
* @param bytes the bytes for which we want a string representation.
* @param count the number of bytes to stop at (which will be coerced into being {@code <=} the
* length of the array).
*/
public static String hexlate (byte[] bytes, int count)
{
if (bytes == null) {
return "";
}
count = Math.min(count, bytes.length);
char[] chars = new char[count*2];
for (int i = 0; i < count; i++) {
int val = bytes[i];
if (val < 0) {
val += 256;
}
chars[2*i] = XLATE.charAt(val/16);
chars[2*i+1] = XLATE.charAt(val%16);
}
return new String(chars);
}
/**
* Generates a string from the supplied bytes that is the HEX encoded representation of those
* bytes.
*/
public static String hexlate (byte[] bytes)
{
return (bytes == null) ? "" : hexlate(bytes, bytes.length);
}
/**
* Joins an array of strings (or objects which will be converted to strings) into a single
* string separated by commas.
*/
public static String join (Object[] values)
{
return join(values, false);
}
/**
* Joins an array of strings into a single string, separated by commas, and optionally escaping
* commas that occur in the individual string values such that a subsequent call to {@link
* #parseStringArray} would recreate the string array properly. Any elements in the values
* array that are null will be treated as an empty string.
*/
public static String join (Object[] values, boolean escape)
{
return join(values, ", ", escape);
}
/**
* Joins the supplied array of strings into a single string separated by the supplied
* separator.
*/
public static String join (Object[] values, String separator)
{
return join(values, separator, false);
}
/**
* Helper function for the various join
methods.
*/
protected static String join (Object[] values, String separator, boolean escape)
{
StringBuilder buf = new StringBuilder();
int vlength = values.length;
for (int i = 0; i < vlength; i++) {
if (i > 0) {
buf.append(separator);
}
String value = (values[i] == null) ? "" : values[i].toString();
buf.append((escape) ? value.replace(",", ",,") : value);
}
return buf.toString();
}
/** Used by {@link #hexlate} and {@link #unhexlate}. */
protected static final String XLATE = "0123456789abcdef";
}