/*
* Copyright 2006-2012 The Scriptella Project Team.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package scriptella.util;
import java.util.Arrays;
import java.util.regex.Pattern;
/**
* Miscellaneous String/CharSequence utility methods.
*
* @author Fyodor Kupolov
* @version 1.0
*/
public final class StringUtils {
private static final String LINE_SEPARATOR = System.getProperty("line.separator");
private static final Pattern ANY_CHAR_REGEX = Pattern.compile(".");
private static final String PASSWORD_MASK = "*";
private StringUtils() {//singleton
}
/**
* Returns true if characters sequence is empty (length=0) or null.
*
* @param cs characters sequence to test.
* @return true if characters sequence is empty (length=0) or null.
*/
public static boolean isEmpty(final CharSequence cs) {
return cs == null || cs.length() == 0;
}
/**
* Returns a trimmed value for specified charsequence
*
* @param cs charsequence to trim.
* @return trimmed value for specified charsequence or empty string if cs=null
*/
public static String nullsafeTrim(final CharSequence cs) {
return cs == null ? "" : cs.toString().trim();
}
/**
* Returns Null safe string representation of specified object.
*
* @param o object to convert to String.
* @return <code>o.toString()</code> or <code>""</code> if <code>o==null</code>.
*/
public static String nullsafeToString(final Object o) {
return o == null ? "" : o.toString();
}
/**
* Checks if specified characters sequence is empty or contains only ascii whitespace characters.
*
* @param cs characters sequence to check.
* @return true if characters sequence is empty or contains only ascii whitespace characters.
*/
public static boolean isAsciiWhitespacesOnly(final CharSequence cs) {
if (cs == null) {
return true;
}
int len = cs.length();
if (len == 0) {
return true;
}
for (int i = 0; i < len; i++) {
if (cs.charAt(i) > ' ') {
return false;
}
}
return true;
}
/**
* Checks if specified characters sequence represents a non negative decimal number.
*
* @param cs characters sequence to check.
* @return true if specified characters sequence represents a non negative decimal number.
*/
public static boolean isDecimalInt(final CharSequence cs) {
if (cs == null) { //null is not a number.
return false;
}
int len = cs.length();
if (len == 0) { //empty string also
return false;
}
for (int i = 0; i < len; i++) {
int c = cs.charAt(i);
if (c < 0x30 || c > 0x39) {
return false;
}
}
return true;
}
private static Pattern WHITESPACES = Pattern.compile("[\\x00-\\x20&&[^\\r\\n]]+");
private static Pattern EOLS = Pattern.compile("[\\r\\n]+");
/**
* Formats specified string for console suitable representation.
* <p>All EOL char sequences are replaced with a single system line.separator,
* and all other whitespace sequences are replaced with a single space.
* <p>String larger than 10KB are trimmed.
*
* @param string string to format. Nulls are allowed.
* @return formatted string.
*/
public static String consoleFormat(String string) {
return consoleFormat(string, 10000);
}
/**
* Formats specified string for console suitable representation.
* <p>All EOL char sequences are replaced with a single system line.separator,
* and all other whitespace sequences are replaced with a single space.
*
* @param string string to format. Nulls are allowed.
* @param maxLength maximum number of characters to show or negative if the string cannot be trimmed.
* @return formatted string.
*/
public static String consoleFormat(String string, int maxLength) {
if (string == null) {
return "";
}
String res = string.trim();
String sep = LINE_SEPARATOR == null ? "\n" : LINE_SEPARATOR;
res = EOLS.matcher(res).replaceAll(sep);
res = WHITESPACES.matcher(res).replaceAll(" ");
if (maxLength > 0 && res.length() > maxLength) {
res = res.substring(0, maxLength) + " ...";
}
return res;
}
/**
* Removes a prefix from a string.
*
* @param string original string. May be null.
* @param prefix prefix to to check and remove. May be null.
* @return string without a prefix, or unchanged string.
*/
public static String removePrefix(String string, String prefix) {
if (prefix != null && string != null && string.startsWith(prefix)) {
return string.substring(prefix.length());
}
return string;
}
/**
* Masks password displaying to user.
*
* @param string password.
* @return masked password or empty string for empty/null password.
*/
public static String getMaskedPassword(String string) {
return string == null ? "" : ANY_CHAR_REGEX.matcher(string).replaceAll(PASSWORD_MASK);
}
/**
* Pads a String with a specified character.
*
* @param str string to pad. Null is treated as empty string.
* @param left true if left pad, false if right
* @param width with of the padded string
* @param padChar character to use for padding
* @return padded string.
*/
public static String pad(String str, boolean left, int width, char padChar) {
String s = str == null ? "" : str;
if (width <= s.length()) {
return s;
}
char[] padChars = new char[width - s.length()];
Arrays.fill(padChars, padChar);
String padStr = new String(padChars);
return left ? padStr + s : s + padStr;
}
}