com.sangupta.jerry.util.StringUtils Maven / Gradle / Ivy
/**
*
* jerry - Common Java Functionality
* Copyright (c) 2012-2014, Sandeep Gupta
*
* http://sangupta.com/projects/jerry
*
* 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 com.sangupta.jerry.util;
import java.nio.charset.Charset;
import java.util.List;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Utility functions around {@link String} objects.
*
* @author sangupta
*
*/
public class StringUtils {
/**
* Logger instance
*/
public static final Logger LOGGER = LoggerFactory.getLogger(StringUtils.class);
/**
* UTF-8 charset object
*/
public static final Charset CHARSET_UTF8 = Charset.forName("UTF8");
/**
* An empty string object containing nothing.
*/
public static final String EMPTY_STRING = "";
/**
* A blank string containing one blank white-space character.
*/
public static final String BLANK_STRING = " ";
/**
* Defines the platform dependent line encoding
*/
public static final String SYSTEM_NEW_LINE = System.getProperty("line.separator");
/**
* Function to give a HEX representation of the byte array in small-case.
*
* @param bytes
* the source byte array
*
* @return the HEX coded string representing the byte array
*/
public static String asHex(byte bytes[]) {
StringBuilder sb = new StringBuilder();
for (int i = 0; i < bytes.length; ++i) {
sb.append(Integer.toHexString((bytes[i] & 0xFF) | 0x100).substring(1, 3));
}
return sb.toString();
}
/**
* Function to return a HEX representation of the given byte in small-case.
*
* @param b
* the byte value
*
* @return the hex representation
*
*/
public static String asHex(byte b) {
return Integer.toHexString((b & 0xFF) | 0x100).substring(1, 3);
}
/**
* Return the {@link String} representation of the byte array. A
* null byte array is converted back to null, an
* empty array to an empty string or the bytes to the actual string based on
* platform encoding.
*
* @param bytes
* the byte array
*
* @return its string representation
*/
public static String asString(byte[] bytes) {
if(bytes == null) {
return null;
}
if(bytes.length == 0) {
return EMPTY_STRING;
}
return new String(bytes);
}
/**
* Return the {@link String} representation of the byte array. A
* null byte array is converted back to null, an
* empty array to an empty string or the bytes to the actual string in UTF-8
* encoding.
*
* @param bytes
* the byte array
*
* @return its string representation
*/
public static String asStringUTF8(byte[] bytes) {
if(bytes == null) {
return null;
}
if(bytes.length == 0) {
return EMPTY_STRING;
}
return new String(bytes, CHARSET_UTF8);
}
/**
* Return the actual array that this hex string represents.
*
* @param hex
* the hex string
*
* @return the actual byte array for the hex string
*/
public static byte[] fromHex(String hex) {
if(AssertUtils.isEmpty(hex)) {
return null;
}
int len = hex.length();
byte[] data = new byte[len / 2];
for (int i = 0; i < len; i += 2) {
data[i / 2] = (byte) ((Character.digit(hex.charAt(i), 16) << 4) + Character.digit(hex.charAt(i+1), 16));
}
return data;
}
/**
* Return true if the string is equal to "true" or "yes" otherwise return
* false.
*
* @param boolString
* string whose content is checked for true or false
*
* @return boolean flag indicating whether the input was true or false
*/
public static boolean getBoolean(String boolString) {
return getBoolean(boolString, false);
}
/**
* Parse the string and return the boolean value for the same. Text such as
* yes and true is treated as {@link Boolean#TRUE}
* . If the string parsing fails, the default value is returned.
*
* @param boolString
* the string to be parsed
*
* @param defaultValue
* the value to be returned, if the string does not match
*
* @return the boolean value as read by parsing the string
*/
public static boolean getBoolean(String boolString, boolean defaultValue) {
if (AssertUtils.isNotEmpty(boolString)) {
boolString = boolString.toLowerCase();
if ("yes".equals(boolString) || "true".equals(boolString)) {
return true;
}
return false;
}
return defaultValue;
}
/**
* Parse and return the int value of the given string. If the string cannot
* be parsed, returns the default value provided
*
* @param string
* the string to be parsed
*
* @param defaultValue
* the value to be returned if parsing string fails
*
* @return the 32-bit value of the string
*/
public static int getIntValue(String string, int defaultValue) {
try {
if(AssertUtils.isNotEmpty(string)) {
return Integer.parseInt(string);
}
} catch(NumberFormatException e) {
LOGGER.debug("error getting integer from string: " + string, e);
}
return defaultValue;
}
/**
* Parse and return the long value of the given string. If the string cannot
* be parsed, returns the default value provided
*
* @param string
* the string to be parsed
*
* @param defaultValue
* the value to be returned if parsing string fails
*
* @return the 64-bit value of the string
*/
public static long getLongValue(String string, long defaultValue) {
try {
if(AssertUtils.isNotEmpty(string)) {
return Long.parseLong(string);
}
} catch(NumberFormatException e) {
LOGGER.debug("error getting long from string: " + string, e);
}
return defaultValue;
}
/**
* Parse and return the float value of the given string. If the string cannot
* be parsed, returns the default value provided
*
* @param string
* the string to be parsed
*
* @param defaultValue
* the value to be returned if parsing string fails
*
* @return the float value of the string
*/
public static float getFloatValue(String string, float defaultValue) {
try {
if(AssertUtils.isNotEmpty(string)) {
return Float.parseFloat(string);
}
} catch(NumberFormatException e) {
LOGGER.debug("error getting long from string: " + string, e);
}
return defaultValue;
}
/**
* Parse and return the double value of the given string. If the string cannot
* be parsed, returns the default value provided
*
* @param string
* the string to be parsed
*
* @param defaultValue
* the value to be returned if parsing string fails
*
* @return the double value of the string
*/
public static double getDoubleValue(String string, double defaultValue) {
try {
if(AssertUtils.isNotEmpty(string)) {
return Double.parseDouble(string);
}
} catch(NumberFormatException e) {
LOGGER.debug("error getting long from string: " + string, e);
}
return defaultValue;
}
/**
* Generate a given appender delimited string of all items in the list. If
* the list has no elements, an empty string is returned back.
*
* @param list
* the list containing objects to be joined
*
* @param appender
* the appender to be used
*
* @return the string representation of list using appender as the delimiter
*/
public static String listToString(List list, String appender) {
if(AssertUtils.isEmpty(list)) {
return EMPTY_STRING;
}
final boolean hasAppender = AssertUtils.isNotEmpty(appender);
StringBuilder builder = new StringBuilder();
for(int index = 0; index < list.size(); index++) {
if(hasAppender && index > 0) {
builder.append(appender);
}
builder.append(list.get(index));
}
return builder.toString();
}
/**
* Check if a value is contained in the list.
*
* @param list
* the list of values
*
* @param value
* the value that needs to be checked for presence in list
*
* @return true if the value exists in list, false
* otherwise.
*
*/
public static boolean contains(String[] list, String value) {
if(list == null) {
return false;
}
if(list.length == 0) {
return false;
}
for(String item : list) {
if(item.equals(value)) {
return true;
}
}
return false;
}
/**
* Return a subset of string from the location where the given 'from' word
* exists.
*
* @param string
* the string from which substring needs to be extracted
*
* @param from
* the string to be looked
*
* @param searchIndex
* the index from which the string needs to be searched
*
* @return the substring after the word is found inside the main string
*/
public static String substringAfter(String string, String from, int searchIndex) {
if(AssertUtils.isEmpty(string)) {
return EMPTY_STRING;
}
if(AssertUtils.isEmpty(from)) {
return string;
}
int index = string.indexOf(from, searchIndex);
if(index == -1) {
return EMPTY_STRING;
}
return string.substring(index + from.length());
}
/**
* Find the substring between the given prefix and suffix.
*
* @param string
* the string which needs to be sub-string'ed
*
* @param prefix
* the string before
*
* @param suffix
* the string after
*
* @return the sub-string between the prefix and suffix
*
*/
public static String substringBetween(String string, String prefix, String suffix) {
return StringUtils.substringBetween(string, prefix, suffix, 0);
}
/**
* Find the substring between the given prefix and suffix.
*
* @param string
* the string which needs to be sub-string'ed
*
* @param prefix
* the string before
*
* @param suffix
* the string after
*
* @param startSearch
* the index to start searching the prefix from
*
* @return the sub-string between the prefix and suffix
*
*/
public static String substringBetween(String string, String prefix, String suffix, int startSearch) {
if(AssertUtils.isEmpty(string)) {
return EMPTY_STRING;
}
int begin = 0, end = string.length();
if(AssertUtils.isNotBlank(prefix)) {
begin = string.indexOf(prefix, startSearch);
if(begin != -1) {
begin += prefix.length();
} else {
begin = 0;
}
}
if(AssertUtils.isNotEmpty(suffix)) {
end = string.indexOf(suffix, begin);
if(end == -1) {
end = string.length();
}
}
return string.substring(begin, end);
}
/**
* Find the last index of searchString inside string, where searchString
* occurs before the suffix in the string.
*
* @param string
* the string in which the search will be performed
*
* @param searchString
* the string that needs to be searched
*
* @param suffix
* the string that decides the end location of the search
*
* @return the index of searchString inside string, terminated at point
* where suffix occurs
*
*/
public static int lastIndexBefore(String string, String searchString, String suffix) {
if(AssertUtils.isEmpty(string)) {
return -1;
}
if(AssertUtils.isEmpty(searchString)) {
return -1;
}
int index = string.indexOf(suffix);
if(index != -1) {
string = string.substring(0, index);
}
return string.lastIndexOf(searchString);
}
/**
* Find the nth index of a string-part inside another string.
*
* @param string
* the string in which the search will be performed
*
* @param searchString
* the string that needs to be searched
*
* @param n
* the occurrence number that we are looking for
*
* @return the index of nth occurrence of searchString inside string
*/
public static int nthIndexOf(String string, String searchString, int n) {
if(n <= 0) {
throw new IllegalArgumentException("n cannot be less than, or equal to zero");
}
if(n == 1) {
return string.indexOf(searchString);
}
int count = 0;
int index = -1;
do {
index = string.indexOf(searchString, index + 1);
if(index == -1) {
return -1;
}
count++;
if(count == n) {
return index;
}
} while(true);
}
/**
* Check if the given string starts with the given prefix, ignoring case.
*
* @param text
* the string to search in
*
* @param prefix
* the prefix to search for
*
* @return true if the string starts with prefix,
* false otherwise
*/
public static boolean startsWithIgnoreCase(String text, String prefix) {
if(AssertUtils.isEmpty(text)) {
return false;
}
if(AssertUtils.isEmpty(prefix)) {
return false;
}
if(text == prefix) {
return true; // same string
}
if(prefix.length() > text.length()) {
return false;
}
if(text.substring(0, prefix.length()).equalsIgnoreCase(prefix)) {
return true;
}
return false;
}
/**
* Check if the given string ends with the given suffix, ignoring case.
*
* @param text
* the string to search in
*
* @param suffix
* the suffix to search for
*
* @return true if the string ends with suffix,
* false otherwise
*/
public static boolean endsWithIgnoreCase(String text, String suffix) {
if(AssertUtils.isEmpty(text)) {
return false;
}
if(AssertUtils.isEmpty(suffix)) {
return false;
}
if(text == suffix) {
return true; // same string
}
int start = text.length() - suffix.length();
if(start < 0) {
return false;
}
if(text.substring(start).equalsIgnoreCase(suffix)) {
return true;
}
return false;
}
}
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