StringUtil.java
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package org.hsqldb.lib;
import java.lang.reflect.Array;
/** Provides a collection of convenience methods for processing and
* creating objects with {@code String} value components.
*
* @author Campbell Burnet (campbell-burnet@users dot sourceforge.net)
* @author Fred Toussi (fredt@users dot sourceforge.net)
* @version 2.7.3
* @since 1.7.0
*/
public class StringUtil {
/**
* If necessary, adds zeros to the beginning of a value so that the total
* length matches the given precision, otherwise trims the right digits.
* Then if maxSize is smaller than precision, trims the right digits to
* maxSize. Negative values are treated as positive
*
* @param value long
* @param precision int
* @param maxSize int
* @return String
*/
public static String toZeroPaddedString(
long value,
int precision,
int maxSize) {
StringBuilder sb = new StringBuilder();
if (value < 0) {
value = -value;
}
String s = Long.toString(value);
if (s.length() > precision) {
s = s.substring(precision);
}
for (int i = s.length(); i < precision; i++) {
sb.append('0');
}
sb.append(s);
if (maxSize < precision) {
sb.setLength(maxSize);
}
return sb.toString();
}
public static String toPaddedString(
String source,
int length,
char pad,
boolean trailing) {
int len = source.length();
if (len >= length) {
return source;
}
StringBuilder sb = new StringBuilder(length);
if (trailing) {
sb.append(source);
}
for (int i = len; i < length; i++) {
sb.append(pad);
}
if (!trailing) {
sb.append(source);
}
return sb.toString();
}
public static String toPaddedString(
String source,
int length,
String pad,
boolean trailing) {
int len = source.length();
if (len == length) {
return source;
}
if (len > length) {
if (trailing) {
return source.substring(0, length);
} else {
return source.substring(len - length, len);
}
}
StringBuilder sb = new StringBuilder(length);
int padedLength = source.length();
int partLength = (length - padedLength) % pad.length();
if (trailing) {
sb.append(source);
}
for (; padedLength + pad.length() <= length;
padedLength += pad.length()) {
sb.append(pad);
}
sb.append(pad, 0, partLength);
if (!trailing) {
sb.append(source);
}
return sb.toString();
}
/**
* Returns a string with non-alphanumeric chars converted to the
* substitute character. A digit first character is also converted.
* By sqlbob@users
* @param source string to convert
* @param substitute character to use
* @return converted string
*/
public static String toLowerSubset(String source, char substitute) {
int len = source.length();
StringBuilder sb = new StringBuilder(len);
char ch;
for (int i = 0; i < len; i++) {
ch = source.charAt(i);
if (!Character.isLetterOrDigit(ch)) {
sb.append(substitute);
} else if ((i == 0) && Character.isDigit(ch)) {
sb.append(substitute);
} else {
sb.append(Character.toLowerCase(ch));
}
}
return sb.toString();
}
/**
* Builds a bracketed CSV list from the array
* @param array an array of Objects
* @return string
*/
public static String arrayToString(Object array) {
int len = Array.getLength(array);
int last = len - 1;
StringBuilder sb = new StringBuilder(2 * (len + 1));
sb.append('{');
for (int i = 0; i < len; i++) {
sb.append(Array.get(array, i));
if (i != last) {
sb.append(',');
}
}
sb.append('}');
return sb.toString();
}
/**
* Builds a CSV list from the specified String[], separator string and
* quote string.
*
* <ul>
* <li>All arguments are assumed to be non-null.
* <li>Separates each list element with the value of the
* {@code separator} argument.
* <li>Prepends and appends each element with the value of the
* {@code quote} argument.
* <li> No attempt is made to escape the quote character sequence if it is
* found internal to a list element.
* </ul>
* @return a CSV list
* @param separator the {@code String} to use as the list element separator
* @param quote the {@code String} with which to quote the list elements
* @param s array of {@code String} objects
*/
public static String getList(String[] s, String separator, String quote) {
int len = s.length;
StringBuilder sb = new StringBuilder(len * 16);
for (int i = 0; i < len; i++) {
sb.append(quote).append(s[i]).append(quote);
if (i + 1 < len) {
sb.append(separator);
}
}
return sb.toString();
}
/**
* Builds a CSV list from the specified int[], separator
* String and quote String.
*
* <ul>
* <li>All arguments are assumed to be non-null.
* <li>Separates each list element with the value of the
* {@code separator} argument.
* <li>Prepends and appends each element with the value of the
* {@code quote} argument.
* </ul>
* @return a CSV list
* @param s the array of int values
* @param separator the {@code String} to use as the separator
* @param quote the {@code String} with which to quote the list elements
*/
public static String getList(int[] s, String separator, String quote) {
int len = s.length;
StringBuilder sb = new StringBuilder(len * 8);
for (int i = 0; i < len; i++) {
sb.append(quote).append(s[i]).append(quote);
if (i + 1 < len) {
sb.append(separator);
}
}
return sb.toString();
}
public static String getList(long[] s, String separator, String quote) {
int len = s.length;
StringBuilder sb = new StringBuilder(len * 8);
for (int i = 0; i < len; i++) {
sb.append(quote).append(s[i]).append(quote);
if (i + 1 < len) {
sb.append(separator);
}
}
return sb.toString();
}
/**
* Builds a CSV list from the specified String[][], separator string and
* quote string.
*
* <ul>
* <li>All arguments are assumed to be non-null.
* <li>Uses only the first element in each subarray.
* <li>Separates each list element with the value of the
* {@code separator} argument.
* <li>Prepends and appends each element with the value of the
* {@code quote} argument.
* <li> No attempt is made to escape the quote character sequence if it is
* found internal to a list element.
* </ul>
* @return a CSV list
* @param separator the {@code String} to use as the list element separator
* @param quote the {@code String} with which to quote the list elements
* @param s the array of {@code String} array objects
*/
public static String getList(String[][] s, String separator, String quote) {
int len = s.length;
StringBuilder sb = new StringBuilder(len * 16);
for (int i = 0; i < len; i++) {
sb.append(quote).append(s[i][0]).append(quote);
if (i + 1 < len) {
sb.append(separator);
}
}
return sb.toString();
}
/**
* Checks if text is empty ({@code characters <= space})
* @return boolean true if text is null or empty, false otherwise
* @param s java.lang.String
*/
public static boolean isEmpty(String s) {
int i = s == null
? 0
: s.length();
while (i > 0) {
if (s.charAt(--i) > ' ') {
return false;
}
}
return true;
}
/**
* Returns the size of substring that does not contain any trailing spaces
* @param s the string
* @return trimmed size
*/
public static int rightTrimSize(String s) {
int i = s.length();
while (i > 0) {
i--;
if (s.charAt(i) != ' ') {
return i + 1;
}
}
return 0;
}
/**
* Skips any spaces at or after start and returns the index of first
* non-space character;
* @param s the string
* @param start index to start
* @return index of first non-space
*/
public static int skipSpaces(String s, int start) {
int limit = s.length();
int i = start;
for (; i < limit; i++) {
if (s.charAt(i) != ' ') {
break;
}
}
return i;
}
/**
* Splits the string into an array, using the separator. If separator is
* not found in the string, the whole string is returned in the array.
*
* @param s the string
* @param separator the separator
* @return array of strings
*/
public static String[] split(String s, String separator) {
HsqlArrayList<String> list = new HsqlArrayList<>();
int currindex = 0;
for (boolean more = true; more; ) {
int nextindex = s.indexOf(separator, currindex);
if (nextindex == -1) {
nextindex = s.length();
more = false;
}
list.add(s.substring(currindex, nextindex));
currindex = nextindex + separator.length();
}
return list.toArray(new String[list.size()]);
}
}