org.whattf.checker.AttributeUtil Maven / Gradle / Ivy
The newest version!
package org.whattf.checker;
import java.util.LinkedList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* Static utilities for working with (X)HTML5 attribute values.
*
* @version $Id$
* @author hsivonen
*/
public class AttributeUtil {
/**
* An empty string array instance.
*/
private final static String[] EMPTY_STRING_ARRAY = {};
/**
* The pattern for extracting an integer by skipping white space and ignoring
* trailing garbage.
*/
private static Pattern INTEGER_PATTERN = Pattern.compile("^[ \t\n\r]*(-?[0-9]+)");
/**
* Private constructor to prevent instantiation.
*/
private AttributeUtil() {
super();
}
/**
* Returns the integer represented by attrVal or
* Integer.MIN_VALUE on error.
*
* @param attrVal a string representing an integer attribute
* value (can be null)
* @return the integer represented by attrVal or
* Integer.MIN_VALUE on error
*/
public static int parseInteger(String attrVal) {
if (attrVal == null) {
return Integer.MIN_VALUE;
}
Matcher m = INTEGER_PATTERN.matcher(attrVal);
if (!m.matches()) {
return Integer.MIN_VALUE;
}
try {
return Integer.parseInt(m.group(1));
} catch (NumberFormatException e) {
return Integer.MIN_VALUE;
}
}
/**
* Returns the non-negative integer represented by
* attrVal or -1 on error.
*
* @param attrVal a string representing a non-negative
* integer attribute value (can be null)
* @return the integer represented by attrVal or
* -1 on error
*/
public static int parseNonNegativeInteger(String attrVal) {
int rv = parseInteger(attrVal);
if (rv < 0) {
return -1;
} else {
return rv;
}
}
/**
* Returns the positive integer represented by
* attrVal or -1 on error.
*
* @param attrVal a string representing a positive
* integer attribute value (can be null)
* @return the integer represented by attrVal or
* -1 on error
*/
public static int parsePositiveInteger(String attrVal) {
int rv = parseInteger(attrVal);
if (rv < 1) {
return -1;
} else {
return rv;
}
}
/**
* Splits the argument on white space.
*
* @param value the attribute value
* @return a string array with zero or more strings none of which
* is the empty string and none of which contains white space characters.
*/
public static String[] split(String value) {
if (value == null || "".equals(value)) {
return EMPTY_STRING_ARRAY;
}
int len = value.length();
List list = new LinkedList();
boolean collectingSpace = true;
int start = 0;
for (int i = 0; i < len; i++) {
char c = value.charAt(i);
if (c == ' ' || c == '\t' || c == '\n' || c == '\r') {
if (!collectingSpace) {
list.add(value.substring(start, i));
collectingSpace = true;
}
} else {
if (collectingSpace) {
start = i;
collectingSpace = false;
}
}
}
if (start < len) {
list.add(value.substring(start, len));
}
return list.toArray(EMPTY_STRING_ARRAY);
}
/**
* Checks if string matches lowerCaseLiteral when
* ASCII-lowercased.
* @param lowerCaseLiteral a lower-case literal
* @param string potentially mixed-case string or null
* @return true if string matches
* lowerCaseLiteral when ASCII-lowercased
*/
public static boolean lowerCaseLiteralEqualsIgnoreAsciiCaseString(String lowerCaseLiteral,
String string) {
if (string == null) {
return false;
}
if (lowerCaseLiteral.length() != string.length()) {
return false;
}
for (int i = 0; i < lowerCaseLiteral.length(); i++) {
char c0 = lowerCaseLiteral.charAt(i);
char c1 = string.charAt(i);
if (c1 >= 'A' && c1 <= 'Z') {
c1 += 0x20;
}
if (c0 != c1) {
return false;
}
}
return true;
}
}