package org.jsoup.helper;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Arrays;
import java.util.Collection;
import java.util.Iterator;
/**
* A minimal String utility class. Designed for internal jsoup use only.
*/
public final class StringUtil {
// memoised padding up to 21
static final String[] padding = {"", " ", " ", " ", " ", " ", " ", " ", " ",
" ", " ", " ", " ", " ", " ", " ",
" ", " ", " ", " ", " "};
/**
* Join a collection of strings by a separator
* @param strings collection of string objects
* @param sep string to place between strings
* @return joined string
*/
public static String join(Collection strings, String sep) {
return join(strings.iterator(), sep);
}
/**
* Join a collection of strings by a separator
* @param strings iterator of string objects
* @param sep string to place between strings
* @return joined string
*/
public static String join(Iterator strings, String sep) {
if (!strings.hasNext())
return "";
String start = strings.next().toString();
if (!strings.hasNext()) // only one, avoid builder
return start;
StringBuilder sb = new StringBuilder(64).append(start);
while (strings.hasNext()) {
sb.append(sep);
sb.append(strings.next());
}
return sb.toString();
}
/**
* Join an array of strings by a separator
* @param strings collection of string objects
* @param sep string to place between strings
* @return joined string
*/
public static String join(String[] strings, String sep) {
return join(Arrays.asList(strings), sep);
}
/**
* Returns space padding
* @param width amount of padding desired
* @return string of spaces * width
*/
public static String padding(int width) {
if (width < 0)
throw new IllegalArgumentException("width must be > 0");
if (width < padding.length)
return padding[width];
char[] out = new char[width];
for (int i = 0; i < width; i++)
out[i] = ' ';
return String.valueOf(out);
}
/**
* Tests if a string is blank: null, empty, or only whitespace (" ", \r\n, \t, etc)
* @param string string to test
* @return if string is blank
*/
public static boolean isBlank(String string) {
if (string == null || string.length() == 0)
return true;
int l = string.length();
for (int i = 0; i < l; i++) {
if (!StringUtil.isWhitespace(string.codePointAt(i)))
return false;
}
return true;
}
/**
* Tests if a string is numeric, i.e. contains only digit characters
* @param string string to test
* @return true if only digit chars, false if empty or null or contains non-digit chars
*/
public static boolean isNumeric(String string) {
if (string == null || string.length() == 0)
return false;
int l = string.length();
for (int i = 0; i < l; i++) {
if (!Character.isDigit(string.codePointAt(i)))
return false;
}
return true;
}
/**
* Tests if a code point is "whitespace" as defined in the HTML spec. Used for output HTML.
* @param c code point to test
* @return true if code point is whitespace, false otherwise
* @see #isActuallyWhitespace(int)
*/
public static boolean isWhitespace(int c){
return c == ' ' || c == '\t' || c == '\n' || c == '\f' || c == '\r';
}
/**
* Tests if a code point is "whitespace" as defined by what it looks like. Used for Element.text etc.
* @param c code point to test
* @return true if code point is whitespace, false otherwise
*/
public static boolean isActuallyWhitespace(int c){
return c == ' ' || c == '\t' || c == '\n' || c == '\f' || c == '\r' || c == 160;
// 160 is (non-breaking space). Not in the spec but expected.
}
public static boolean isInvisibleChar(int c) {
return Character.getType(c) == 16 && (c == 8203 || c == 8204 || c == 8205 || c == 173);
// zero width sp, zw non join, zw join, soft hyphen
}
/**
* Normalise the whitespace within this string; multiple spaces collapse to a single, and all whitespace characters
* (e.g. newline, tab) convert to a simple space
* @param string content to normalise
* @return normalised string
*/
public static String normaliseWhitespace(String string) {
StringBuilder sb = StringUtil.stringBuilder();
appendNormalisedWhitespace(sb, string, false);
return sb.toString();
}
/**
* After normalizing the whitespace within a string, appends it to a string builder.
* @param accum builder to append to
* @param string string to normalize whitespace within
* @param stripLeading set to true if you wish to remove any leading whitespace
*/
public static void appendNormalisedWhitespace(StringBuilder accum, String string, boolean stripLeading) {
boolean lastWasWhite = false;
boolean reachedNonWhite = false;
int len = string.length();
int c;
for (int i = 0; i < len; i+= Character.charCount(c)) {
c = string.codePointAt(i);
if (isActuallyWhitespace(c)) {
if ((stripLeading && !reachedNonWhite) || lastWasWhite)
continue;
accum.append(' ');
lastWasWhite = true;
}
else if (!isInvisibleChar(c)) {
accum.appendCodePoint(c);
lastWasWhite = false;
reachedNonWhite = true;
}
}
}
public static boolean in(final String needle, final String... haystack) {
final int len = haystack.length;
for (int i = 0; i < len; i++) {
if (haystack[i].equals(needle))
return true;
}
return false;
}
public static boolean inSorted(String needle, String[] haystack) {
return Arrays.binarySearch(haystack, needle) >= 0;
}
/**
* Create a new absolute URL, from a provided existing absolute URL and a relative URL component.
* @param base the existing absolute base URL
* @param relUrl the relative URL to resolve. (If it's already absolute, it will be returned)
* @return the resolved absolute URL
* @throws MalformedURLException if an error occurred generating the URL
*/
public static URL resolve(URL base, String relUrl) throws MalformedURLException {
// workaround: java resolves '//path/file + ?foo' to '//path/?foo', not '//path/file?foo' as desired
if (relUrl.startsWith("?"))
relUrl = base.getPath() + relUrl;
// workaround: //example.com + ./foo = //example.com/./foo, not //example.com/foo
if (relUrl.indexOf('.') == 0 && base.getFile().indexOf('/') != 0) {
base = new URL(base.getProtocol(), base.getHost(), base.getPort(), "/" + base.getFile());
}
return new URL(base, relUrl);
}
/**
* Create a new absolute URL, from a provided existing absolute URL and a relative URL component.
* @param baseUrl the existing absolute base URL
* @param relUrl the relative URL to resolve. (If it's already absolute, it will be returned)
* @return an absolute URL if one was able to be generated, or the empty string if not
*/
public static String resolve(final String baseUrl, final String relUrl) {
URL base;
try {
try {
base = new URL(baseUrl);
} catch (MalformedURLException e) {
// the base is unsuitable, but the attribute/rel may be abs on its own, so try that
URL abs = new URL(relUrl);
return abs.toExternalForm();
}
return resolve(base, relUrl).toExternalForm();
} catch (MalformedURLException e) {
return "";
}
}
/**
* Maintains a cached StringBuilder, to minimize new StringBuilder GCs. Prevents it from growing too big per thread.
* Care must be taken to not grab more than one in the same stack (not locked or mutexed or anything).
* @return an empty StringBuilder
*/
public static StringBuilder stringBuilder() {
StringBuilder sb = stringLocal.get();
if (sb.length() > MaxCachedBuilderSize) {
sb = new StringBuilder(MaxCachedBuilderSize);
stringLocal.set(sb);
} else {
sb.delete(0, sb.length());
}
return sb;
}
private static final int MaxCachedBuilderSize = 8 * 1024;
private static final ThreadLocal<StringBuilder> stringLocal = new ThreadLocal<StringBuilder>(){
@Override
protected StringBuilder initialValue() {
return new StringBuilder(MaxCachedBuilderSize);
}
};
}
