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Panda Core is the core module of Panda Framework, it contains commonly used utility classes similar to apache-commons.
package panda.lang;
import java.io.IOException;
import java.util.List;
import java.util.regex.Pattern;
import panda.bean.BeanHandler;
import panda.bean.Beans;
import panda.el.EL;
import panda.io.Streams;
import panda.io.stream.CharSequenceReader;
import panda.io.stream.CsvReader;
import panda.io.stream.CsvWriter;
import panda.io.stream.StringBuilderWriter;
/**
* Utility class for Text.
*
*/
public abstract class Texts {
public final static String ELLIPSIS = "...";
// Wrapping
// --------------------------------------------------------------------------
/**
*
* Wraps a single line of text, identifying words by ' '.
*
*
* New lines will be separated by the system property line separator. Very long words, such as
* URLs will not be wrapped.
*
*
* Leading spaces on a new line are stripped. Trailing spaces are not stripped.
*
*
*
* wrap(null, *) = null
* wrap("", *) = ""
*
*
* @param str the String to be word wrapped, may be null
* @param wrapLength the column to wrap the words at, less than 1 is treated as 1
* @return a line with newlines inserted, null if null input
*/
public static String wrap(String str, int wrapLength) {
return wrap(str, wrapLength, null, false);
}
/**
*
* Wraps a single line of text, identifying words by ' '.
*
*
* Leading spaces on a new line are stripped. Trailing spaces are not stripped.
*
*
*
* wrap(null, *, *, *) = null
* wrap("", *, *, *) = ""
*
*
* @param str the String to be word wrapped, may be null
* @param wrapLength the column to wrap the words at, less than 1 is treated as 1
* @param newLineStr the string to insert for a new line, null uses the system
* property line separator
* @param wrapLongWords true if long words (such as URLs) should be wrapped
* @return a line with newlines inserted, null if null input
*/
public static String wrap(String str, int wrapLength, String newLineStr, boolean wrapLongWords) {
if (str == null) {
return null;
}
if (newLineStr == null) {
newLineStr = Systems.LINE_SEPARATOR;
}
if (wrapLength < 1) {
wrapLength = 1;
}
int inputLineLength = str.length();
int offset = 0;
StringBuilder wrappedLine = new StringBuilder(inputLineLength + 32);
while (inputLineLength - offset > wrapLength) {
if (str.charAt(offset) == ' ') {
offset++;
continue;
}
int spaceToWrapAt = str.lastIndexOf(' ', wrapLength + offset);
if (spaceToWrapAt >= offset) {
// normal case
wrappedLine.append(str.substring(offset, spaceToWrapAt));
wrappedLine.append(newLineStr);
offset = spaceToWrapAt + 1;
}
else {
// really long word or URL
if (wrapLongWords) {
// wrap really long word one line at a time
wrappedLine.append(str.substring(offset, wrapLength + offset));
wrappedLine.append(newLineStr);
offset += wrapLength;
}
else {
// do not wrap really long word, just extend beyond limit
spaceToWrapAt = str.indexOf(' ', wrapLength + offset);
if (spaceToWrapAt >= 0) {
wrappedLine.append(str.substring(offset, spaceToWrapAt));
wrappedLine.append(newLineStr);
offset = spaceToWrapAt + 1;
}
else {
wrappedLine.append(str.substring(offset));
offset = inputLineLength;
}
}
}
}
// Whatever is left in line is short enough to just pass through
wrappedLine.append(str.substring(offset));
return wrappedLine.toString();
}
// Capitalizing
// -----------------------------------------------------------------------
/**
*
* Capitalizes all the whitespace separated words in a String. Only the first letter of each
* word is changed. To convert the rest of each word to lowercase at the same time, use
* {@link #capitalizeFully(String)}.
*
*
* Whitespace is defined by {@link Character#isWhitespace(char)}. A null input
* String returns null. Capitalization uses the Unicode title case, normally
* equivalent to upper case.
*
*
*
* capitalize(null) = null
* capitalize("") = ""
* capitalize("i am FINE") = "I Am FINE"
*
*
* @param str the String to capitalize, may be null
* @return capitalized String, null if null String input
* @see #uncapitalize(String)
* @see #capitalizeFully(String)
*/
public static String capitalize(String str) {
return capitalize(str, null);
}
/**
*
* Capitalizes all the delimiter separated words in a String. Only the first letter of each word
* is changed. To convert the rest of each word to lowercase at the same time, use
* {@link #capitalizeFully(String, char[])}.
*
*
* The delimiters represent a set of characters understood to separate words. The first string
* character and the first non-delimiter character after a delimiter will be capitalized.
*
*
* A null input String returns null. Capitalization uses the Unicode
* title case, normally equivalent to upper case.
*
*
*
* capitalize(null, *) = null
* capitalize("", *) = ""
* capitalize(*, new char[0]) = *
* capitalize("i am fine", null) = "I Am Fine"
* capitalize("i aM.fine", {'.'}) = "I aM.Fine"
*
*
* @param str the String to capitalize, may be null
* @param delimiters set of characters to determine capitalization, null means whitespace
* @return capitalized String, null if null String input
* @see #uncapitalize(String)
* @see #capitalizeFully(String)
*/
public static String capitalize(String str, char... delimiters) {
int delimLen = delimiters == null ? -1 : delimiters.length;
if (Strings.isEmpty(str) || delimLen == 0) {
return str;
}
char[] buffer = str.toCharArray();
boolean capitalizeNext = true;
for (int i = 0; i < buffer.length; i++) {
char ch = buffer[i];
if (isDelimiter(ch, delimiters)) {
capitalizeNext = true;
}
else if (capitalizeNext) {
buffer[i] = Character.toTitleCase(ch);
capitalizeNext = false;
}
}
return new String(buffer);
}
// -----------------------------------------------------------------------
/**
*
* Converts all the whitespace separated words in a String into capitalized words, that is each
* word is made up of a titlecase character and then a series of lowercase characters.
*
*
* Whitespace is defined by {@link Character#isWhitespace(char)}. A null input
* String returns null. Capitalization uses the Unicode title case, normally
* equivalent to upper case.
*
*
*
* capitalizeFully(null) = null
* capitalizeFully("") = ""
* capitalizeFully("i am FINE") = "I Am Fine"
*
*
* @param str the String to capitalize, may be null
* @return capitalized String, null if null String input
*/
public static String capitalizeFully(String str) {
return capitalizeFully(str, null);
}
/**
*
* Converts all the delimiter separated words in a String into capitalized words, that is each
* word is made up of a titlecase character and then a series of lowercase characters.
*
*
* The delimiters represent a set of characters understood to separate words. The first string
* character and the first non-delimiter character after a delimiter will be capitalized.
*
*
* A null input String returns null. Capitalization uses the Unicode
* title case, normally equivalent to upper case.
*
*
*
* capitalizeFully(null, *) = null
* capitalizeFully("", *) = ""
* capitalizeFully(*, null) = *
* capitalizeFully(*, new char[0]) = *
* capitalizeFully("i aM.fine", {'.'}) = "I am.Fine"
*
*
* @param str the String to capitalize, may be null
* @param delimiters set of characters to determine capitalization, null means whitespace
* @return capitalized String, null if null String input
*/
public static String capitalizeFully(String str, char... delimiters) {
int delimLen = delimiters == null ? -1 : delimiters.length;
if (Strings.isEmpty(str) || delimLen == 0) {
return str;
}
str = str.toLowerCase();
return capitalize(str, delimiters);
}
// -----------------------------------------------------------------------
/**
*
* Uncapitalizes all the whitespace separated words in a String. Only the first letter of each
* word is changed.
*
*
* Whitespace is defined by {@link Character#isWhitespace(char)}. A null input
* String returns null.
*
*
*
* uncapitalize(null) = null
* uncapitalize("") = ""
* uncapitalize("I Am FINE") = "i am fINE"
*
*
* @param str the String to uncapitalize, may be null
* @return uncapitalized String, null if null String input
* @see #capitalize(String)
*/
public static String uncapitalize(String str) {
return uncapitalize(str, null);
}
/**
*
* Uncapitalizes all the whitespace separated words in a String. Only the first letter of each
* word is changed.
*
*
* The delimiters represent a set of characters understood to separate words. The first string
* character and the first non-delimiter character after a delimiter will be uncapitalized.
*
*
* Whitespace is defined by {@link Character#isWhitespace(char)}. A null input
* String returns null.
*
*
*
* uncapitalize(null, *) = null
* uncapitalize("", *) = ""
* uncapitalize(*, null) = *
* uncapitalize(*, new char[0]) = *
* uncapitalize("I AM.FINE", {'.'}) = "i AM.fINE"
*
*
* @param str the String to uncapitalize, may be null
* @param delimiters set of characters to determine uncapitalization, null means whitespace
* @return uncapitalized String, null if null String input
* @see #capitalize(String)
*/
public static String uncapitalize(String str, char... delimiters) {
int delimLen = delimiters == null ? -1 : delimiters.length;
if (Strings.isEmpty(str) || delimLen == 0) {
return str;
}
char[] buffer = str.toCharArray();
boolean uncapitalizeNext = true;
for (int i = 0; i < buffer.length; i++) {
char ch = buffer[i];
if (isDelimiter(ch, delimiters)) {
uncapitalizeNext = true;
}
else if (uncapitalizeNext) {
buffer[i] = Character.toLowerCase(ch);
uncapitalizeNext = false;
}
}
return new String(buffer);
}
// -----------------------------------------------------------------------
/**
*
* Swaps the case of a String using a word based algorithm.
*
*
* - Upper case character converts to Lower case
* - Title case character converts to Lower case
* - Lower case character after Whitespace or at start converts to Title case
* - Other Lower case character converts to Upper case
*
*
* Whitespace is defined by {@link Character#isWhitespace(char)}. A null input
* String returns null.
*
*
*
* Strings.swapCase(null) = null
* Strings.swapCase("") = ""
* Strings.swapCase("The dog has a BONE") = "tHE DOG HAS A bone"
*
*
* @param str the String to swap case, may be null
* @return the changed String, null if null String input
*/
public static String swapCase(String str) {
if (Strings.isEmpty(str)) {
return str;
}
char[] buffer = str.toCharArray();
boolean whitespace = true;
for (int i = 0; i < buffer.length; i++) {
char ch = buffer[i];
if (Character.isUpperCase(ch)) {
buffer[i] = Character.toLowerCase(ch);
whitespace = false;
}
else if (Character.isTitleCase(ch)) {
buffer[i] = Character.toLowerCase(ch);
whitespace = false;
}
else if (Character.isLowerCase(ch)) {
if (whitespace) {
buffer[i] = Character.toTitleCase(ch);
whitespace = false;
}
else {
buffer[i] = Character.toUpperCase(ch);
}
}
else {
whitespace = Character.isWhitespace(ch);
}
}
return new String(buffer);
}
// -----------------------------------------------------------------------
/**
*
* Extracts the initial letters from each word in the String.
*
*
* The first letter of the string and all first letters after whitespace are returned as a new
* string. Their case is not changed.
*
*
* Whitespace is defined by {@link Character#isWhitespace(char)}. A null input
* String returns null.
*
*
*
* initials(null) = null
* initials("") = ""
* initials("Ben John Lee") = "BJL"
* initials("Ben J.Lee") = "BJ"
*
*
* @param str the String to get initials from, may be null
* @return String of initial letters, null if null String input
* @see #initials(String,char[])
*/
public static String initials(String str) {
return initials(str, null);
}
/**
*
* Extracts the initial letters from each word in the String.
*
*
* The first letter of the string and all first letters after the defined delimiters are
* returned as a new string. Their case is not changed.
*
*
* If the delimiters array is null, then Whitespace is used. Whitespace is defined by
* {@link Character#isWhitespace(char)}. A null input String returns
* null. An empty delimiter array returns an empty String.
*
*
*
* initials(null, *) = null
* initials("", *) = ""
* initials("Ben John Lee", null) = "BJL"
* initials("Ben J.Lee", null) = "BJ"
* initials("Ben J.Lee", [' ','.']) = "BJL"
* initials(*, new char[0]) = ""
*
*
* @param str the String to get initials from, may be null
* @param delimiters set of characters to determine words, null means whitespace
* @return String of initial letters, null if null String input
* @see #initials(String)
*/
public static String initials(String str, char... delimiters) {
if (Strings.isEmpty(str)) {
return str;
}
if (delimiters != null && delimiters.length == 0) {
return "";
}
int strLen = str.length();
char[] buf = new char[strLen / 2 + 1];
int count = 0;
boolean lastWasGap = true;
for (int i = 0; i < strLen; i++) {
char ch = str.charAt(i);
if (isDelimiter(ch, delimiters)) {
lastWasGap = true;
}
else if (lastWasGap) {
buf[count++] = ch;
lastWasGap = false;
}
else {
continue; // ignore ch
}
}
return new String(buf, 0, count);
}
// -----------------------------------------------------------------------
/**
* Is the character a delimiter.
*
* @param ch the character to check
* @param delimiters the delimiters
* @return true if it is a delimiter
*/
private static boolean isDelimiter(char ch, char[] delimiters) {
if (delimiters == null) {
return Character.isWhitespace(ch);
}
for (char delimiter : delimiters) {
if (ch == delimiter) {
return true;
}
}
return false;
}
// -----------------------------------------------------------------------
public static interface Evaluator {
Object evaluate(String expression);
}
public static class BeanEvaluator implements Evaluator {
private Object context;
@SuppressWarnings("rawtypes")
private BeanHandler beanh;
public BeanEvaluator(Object context) {
this.context = context;
this.beanh = Beans.i().getBeanHandler(context.getClass());
}
@SuppressWarnings("unchecked")
public Object evaluate(String expression) {
return beanh.getBeanValue(context, expression);
}
}
public static class ELEvaluator implements Evaluator {
private Object context;
public ELEvaluator(Object context) {
this.context = context;
}
public Object evaluate(String expression) {
return new EL(expression).eval(context);
}
}
/**
* translate "${a}-${b}" with Map { "a": 1, "b": 2 } -> "1-2".
*
* @param expression expression
* @param wrapper object wrapper
* @return translated string
*/
public static String translate(String expression, Object wrapper) {
return translate(expression, wrapper, '$');
}
/**
* translate "${a}-${b}" with Map { "a": 1, "b": 2 } -> "1-2".
*
* @param expression expression
* @param wrapper object wrapper
* @param prefix prefix char
* @return translated string
*/
public static String translate(String expression, Object wrapper, char prefix) {
if (Strings.isEmpty(expression) || wrapper == null) {
return expression;
}
Evaluator eva = new BeanEvaluator(wrapper);
return translate(expression, eva, prefix, '{', '}');
}
/**
* translate "${a}-${b}" with Map { "a": 1, "b": 2 } -> "1-2".
*
* @param expression expression
* @param wrapper object wrapper
* @return translated string
*/
public static String elTranslate(String expression, Object wrapper) {
return elTranslate(expression, wrapper, Chars.DOLLAR);
}
/**
* translate "${a}-${b}" with Map { "a": 1, "b": 2 } -> "1-2".
*
* @param expression expression
* @param wrapper object wrapper
* @param prefix prefix char
* @return translated string
*/
public static String elTranslate(String expression, Object wrapper, char prefix) {
if (Strings.isEmpty(expression) || wrapper == null) {
return expression;
}
Evaluator eva = new ELEvaluator(wrapper);
return translate(expression, eva, prefix, Chars.BRACES_LEFT, Chars.BRACES_RIGHT);
}
/**
* translate "${a}-${b}" with Map { "a": 1, "b": 2 } -> "1-2".
*
* @param prefix prefix char $ or %
* @param open open char ( or {
* @param close close char ) or }
* @param expression expression string
* @param eval object evaluator
* @return translated string
*/
public static String translate(String expression, Evaluator eval, char prefix, char open, char close) {
if (Strings.isEmpty(expression) || eval == null) {
return expression;
}
int x = 0;
int len = expression.length();
StringBuilder sb = null;
for (int i = 0; i < len; i++) {
char c = expression.charAt(i);
if (c == prefix && i < len - 1 && expression.charAt(i + 1) == open) {
String pn = null;
int j = i + 2;
for (; j < len; j++) {
if (expression.charAt(j) == close) {
pn = expression.substring(i + 2, j);
break;
}
}
if (pn == null) {
throw new IllegalArgumentException("Illegal statement (" + i + "): unexpected end of tag reached.");
}
else if (pn.length() < 1) {
throw new IllegalArgumentException("Illegal statement (" + i + "): the paramenter can not be empty.");
}
Object v = eval.evaluate(pn);
if (v != null) {
if (sb == null) {
sb = new StringBuilder();
}
sb.append(expression.substring(x, i));
sb.append(v);
x = j + 1;
}
i = j;
}
}
if (sb != null && x < len) {
sb.append(expression.substring(x, len));
}
return sb == null ? expression : sb.toString();
}
// -----------------------------------------------------------------------
/**
* convert a string to a camel style word
*
*
* camelWord("hello-world", '-') => "helloWorld"
*
*
* @param cs the input string
* @param c separator
* @return camel style word
*/
public static String camelWord(CharSequence cs, char c) {
if (cs == null) {
return null;
}
if (cs.length() < 1) {
return Strings.EMPTY;
}
StringBuilder sb = new StringBuilder();
int len = cs.length();
for (int i = 0; i < len; i++) {
char ch = cs.charAt(i);
if (ch == c) {
do {
i++;
if (i >= len) {
return sb.toString();
}
ch = cs.charAt(i);
}
while (ch == c);
sb.append(Character.toUpperCase(ch));
}
else {
sb.append(ch);
}
}
return sb.toString();
}
/**
* convert a camel style word to a string joined by sepecified separator
*
*
* uncamelWord("helloWorld", '-') => "hello-world"
*
*
* @param cs the input string
* @param c separator
* @return converted string
*/
public static String uncamelWord(CharSequence cs, char c) {
if (cs == null) {
return null;
}
if (cs.length() < 1) {
return Strings.EMPTY;
}
StringBuilder sb = new StringBuilder();
int len = cs.length();
for (int i = 0; i < len; i++) {
char ch = cs.charAt(i);
if (Character.isUpperCase(ch)) {
if (i > 0) {
sb.append(c);
}
sb.append(Character.toLowerCase(ch));
}
else {
sb.append(ch);
}
}
return sb.toString();
}
// -----------------------------------------------------------------------
/**
* toCsv
*
* @param lines lines
* @return csv string
*/
public static String toCsv(List lines) {
if (lines == null) {
return null;
}
StringBuilderWriter sw = new StringBuilderWriter();
CsvWriter cw = new CsvWriter(sw);
try {
cw.writeAll(lines);
return sw.toString();
}
catch (IOException e) {
throw Exceptions.wrapThrow(e);
}
finally {
Streams.safeClose(cw);
}
}
/**
* parse csv string
*
* @param str string
* @return string list
*/
public static List parseCsv(String str) {
return parseCsv(str, Chars.COMMA);
}
/**
* parse csv string
*
* @param str string
* @param separator the delimiter to use for separating entries.
* @return string list
*/
public static List parseCsv(String str, char separator) {
return parseCsv(str, Chars.COMMA, Chars.DOUBLE_QUOTE);
}
/**
* parse csv string
*
* @param str string
* @param separator the delimiter to use for separating entries.
* @param quotechar the character to use for quoted elements
* @return string list
*/
public static List parseCsv(CharSequence str, char separator, char quotechar) {
if (str == null) {
return null;
}
CsvReader cr = new CsvReader(new CharSequenceReader(str), separator, quotechar);
try {
return cr.readList();
}
catch (IOException e) {
throw new RuntimeException(e);
}
finally {
Streams.safeClose(cr);
}
}
// -----------------------------------------------------------------------
/**
* Truncate a string and add an ellipsis ('...') to the end if it exceeds the specified length
*
* @param str value The string to truncate
* @param len length The maximum length to allow before truncating
* @return The converted text
*/
public static String ellipsis(String str, int len) {
return ellipsis(str, len, ELLIPSIS);
}
/**
* Truncate a string and add an ellipsis ('...') to the end if it exceeds the specified length
*
* @param str value The string to truncate
* @param len length The maximum length to allow before truncating
* @param ellipsis the ellipsis string
* @return The converted textELLIPSIS
*/
public static String ellipsis(String str, int len, String ellipsis) {
if (str == null) {
return null;
}
if (str.length() > len) {
if (len <= ellipsis.length()) {
return ellipsis.substring(0, len);
}
return str.substring(0, len - ellipsis.length()) + ellipsis;
}
return str;
}
/**
* Truncate a string and add an ellipsis ('...') to the end if it exceeds the specified length
* the length of charCodeAt(i) > 0xFF will be treated as 2.
*
* @param str value The string to truncate
* @param len length The maximum length to allow before truncating
* @return The converted text
*/
public static String ellipsiz(String str, int len) {
return ellipsiz(str, len, ELLIPSIS);
}
/**
* Truncate a string and add an ellipsis ('...') to the end if it exceeds the specified length
* the length of charCodeAt(i) > 0xFF will be treated as 2.
*
* @param str value The string to truncate
* @param len length The maximum length to allow before truncating
* @param ellipsis the ellipsis string
* @return The converted text
*/
public static String ellipsiz(String str, int len, String ellipsis) {
if (str == null) {
return null;
}
int max = len - ellipsis.length();
int sz = 0, j = 0;
for (int i = 0; i < str.length(); i++) {
sz++;
if (str.charAt(i) > 0xFF) {
sz++;
}
if (sz > max && j == 0) {
j = i;
}
if (sz > len) {
if (len <= ellipsis.length()) {
return ellipsis.substring(0, len);
}
return str.substring(0, j) + ellipsis;
}
}
return str;
}
// -----------------------------------------------------------------------
private static class XmlPattern {
static Pattern p0 = Pattern.compile(".+]*>$");
static Pattern p1 = Pattern.compile("^$");
static Pattern p2 = Pattern.compile("^<\\w[^>]*[^/]>.*$");
static Pattern p3 = Pattern.compile("(>)(<)(/*)");
}
/**
* prettify xml
*
* @param xml xml string
* @return prettified xml
*/
public static String prettifyXml(String xml) {
StringBuilder fmt = new StringBuilder();
xml = XmlPattern.p3.matcher(xml).replaceAll("$1\n$2$3");
String[] xs = Strings.split(xml, Strings.CRLF);
int pad = 0;
for (int i = 0; i < xs.length; i++) {
String node = xs[i];
int indent = 0;
if (XmlPattern.p0.matcher(node).matches()) {
indent = 0;
}
else if (XmlPattern.p1.matcher(node).matches()) {
if (pad != 0) {
pad -= 1;
}
}
else if (XmlPattern.p2.matcher(node).matches()) {
indent = 1;
}
else {
indent = 0;
}
fmt.append(Strings.leftPad(Strings.EMPTY, pad * 2, ' ')).append(node).append(Strings.CRLF);
pad += indent;
}
return fmt.toString();
}
// -----------------------------------------------------------------------
/**
* http://en.wikibooks.org/wiki/Algorithm_Implementation/Strings/Levenshtein_distance#Java
*
* @param s0 the string
* @param s1 the string
* @return the Levenshtein distance
*/
public static int computeLevenshteinDistance(String s0, String s1) {
int len0 = s0.length() + 1;
int len1 = s1.length() + 1;
// the array of distances
int[] cost = new int[len0];
int[] newcost = new int[len0];
// initial cost of skipping prefix in String s0
for (int i = 0; i < len0; i++)
cost[i] = i;
// dynamicaly computing the array of distances
// transformation cost for each letter in s1
for (int j = 1; j < len1; j++) {
// initial cost of skipping prefix in String s1
newcost[0] = j - 1;
// transformation cost for each letter in s0
for (int i = 1; i < len0; i++) {
// matching current letters in both strings
int match = (s0.charAt(i - 1) == s1.charAt(j - 1)) ? 0 : 1;
// computing cost for each transformation
int cost_replace = cost[i - 1] + match;
int cost_insert = cost[i] + 1;
int cost_delete = newcost[i - 1] + 1;
// keep minimum cost
newcost[i] = Math.min(Math.min(cost_insert, cost_delete), cost_replace);
}
// swap cost/newcost arrays
int[] swap = cost;
cost = newcost;
newcost = swap;
}
// the distance is the cost for transforming all letters in both strings
return cost[len0 - 1];
}
public static String maskPassword(String pwd) {
if (Strings.isEmpty(pwd)) {
return pwd;
}
StringBuilder sb = new StringBuilder(pwd.length());
for (int i = 0; i < pwd.length(); i++) {
if (i > 1 && i < pwd.length() - 1) {
sb.append('*');
}
else {
sb.append(pwd.charAt(i));
}
}
return sb.toString();
}
}