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Simply utility methods used across other Molindo projects
/**
* Copyright 2010 Molindo GmbH
*
* 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 at.molindo.utils.data;
import java.util.Arrays;
import java.util.Iterator;
import java.util.Locale;
import java.util.NoSuchElementException;
import at.molindo.utils.collections.IteratorUtils;
public class StringUtils {
private StringUtils() {
}
public static boolean empty(String string) {
return string == null || string.isEmpty();
}
public static String trim(String string) {
return string == null ? null : string.trim();
}
public static String trimLeading(String string) {
if (string == null) {
return null;
}
int length = string.length();
int i = 0;
while (i < length && string.charAt(i) == ' ') {
i++;
}
return string.substring(i);
}
public static String trimTrailing(String string) {
if (string == null) {
return null;
}
int i = string.length() - 1;
while (i >= 0 && string.charAt(i) == ' ') {
i--;
}
return string.substring(0, i + 1);
}
public static String sub(String s, int length) {
return sub(s, "", length);
}
public static String sub(String s, String suffix, int maxLength) {
if (suffix == null) {
suffix = "";
}
if (maxLength < suffix.length()) {
throw new IllegalArgumentException("suffix ('" + suffix + "') must not be longer than maxLength ("
+ maxLength + ")");
}
if (s == null || s.length() <= maxLength) {
return s;
}
return s.substring(0, maxLength - suffix.length()) + suffix;
}
public static String subPre(String s, int length) {
return subPre(s, "", length);
}
public static String subPre(String s, String prefix, int maxLength) {
if (prefix == null) {
prefix = "";
}
if (maxLength < prefix.length()) {
throw new IllegalArgumentException("prefix ('" + prefix + "') must not be longer than maxLength ("
+ maxLength + ")");
}
if (s == null || s.length() <= maxLength) {
return s;
}
return prefix + s.substring(s.length() - maxLength + prefix.length(), s.length());
}
public static String afterFirst(final String string, final String delim) {
if (string == null) {
return null;
}
final int index = string.indexOf(delim);
if (index == -1) {
return "";
}
return string.substring(index + delim.length());
}
public static String afterLast(final String string, final String delim) {
if (string == null) {
return null;
}
final int index = string.lastIndexOf(delim);
if (index == -1) {
return "";
}
return string.substring(index + delim.length());
}
public static String beforeFirst(final String string, final String delim) {
if (string == null) {
return null;
}
final int index = string.indexOf(delim);
if (index == -1) {
return "";
}
return string.substring(0, index);
}
public static String beforeLast(final String string, final String delim) {
if (string == null) {
return null;
}
final int index = string.lastIndexOf(delim);
if (index == -1) {
return "";
}
return string.substring(0, index);
}
public static String startWith(String string, String prefix) {
if (empty(string)) {
return prefix;
} else if (string.startsWith(prefix)) {
return string;
} else {
return prefix + string;
}
}
public static String endWith(String string, String suffix) {
if (empty(string)) {
return suffix;
} else if (string.endsWith(suffix)) {
return string;
} else {
return string + suffix;
}
}
public static String trailing(String string, String suffix) {
if (string == null) {
return null;
}
return suffix == null || string.endsWith(suffix) ? string : string + suffix;
}
public static String leading(String string, String prefix) {
if (string == null) {
return null;
}
return prefix == null || string.startsWith(prefix) ? string : prefix + string;
}
public static String stripTrailing(String string, String suffix) {
if (string == null) {
return null;
}
if (suffix != null && string.endsWith(suffix)) {
return string.substring(0, string.length() - suffix.length());
} else {
return string;
}
}
public static String stripLeading(String string, String prefix) {
if (string == null) {
return null;
}
if (prefix != null && string.startsWith(prefix)) {
return string.substring(prefix.length());
} else {
return string;
}
}
/**
*
* @param string
* @param delim
* @param a
* @return number of string written to a
* @throws IllegalArgumentException
* if a is of length 0
* @throws ArrayIndexOutOfBoundsException
* if a is too small to fit all strings
* @see #split(String, String)
*/
public static int split(String string, String delim, String[] a) {
if (a.length == 0) {
throw new IllegalArgumentException();
}
int idx = 0;
for (String s : split(string, delim)) {
a[idx++] = s;
}
return idx;
}
/**
* splits a string into a pair at the first occurence of delim
*
* @param string
* @param delim
* @return
*/
public static Pair pair(String string, String delim) {
if (string == null) {
return Pair.pair("", "");
}
int idx = string.indexOf(delim);
if (idx < 0) {
return Pair.pair(string, "");
} else {
return Pair.pair(string.substring(0, idx), string.substring(idx + 1));
}
}
/**
* null-safe equals
*
* @param s1
* @param s2
* @return
*/
public static boolean equals(String s1, String s2) {
return ObjectUtils.equals(s1, s2);
}
public static String upper(String s) {
return upper(s, Locale.getDefault());
}
private static String upper(String s, Locale locale) {
return s == null ? null : s.toUpperCase(locale);
}
public static String upperFirst(String s) {
return upperFirst(s, Locale.getDefault());
}
public static String upperFirst(String s, Locale locale) {
if (s == null || s.length() < 1) {
return s;
} else {
return s.substring(0, 1).toUpperCase(locale) + s.substring(1);
}
}
public static String lower(String s) {
return lower(s, Locale.getDefault());
}
private static String lower(String s, Locale locale) {
return s == null ? null : s.toLowerCase(locale);
}
public static String lowerFirst(String s) {
return lowerFirst(s, Locale.getDefault());
}
public static String lowerFirst(String s, Locale locale) {
if (s == null || s.length() < 1) {
return s;
} else {
return s.substring(0, 1).toLowerCase(locale) + s.substring(1);
}
}
public static Iterable split(final String string, final String split) {
return split(string, split, Integer.MAX_VALUE);
}
public static Iterable split(final String string, final String split, final int max) {
if (string == null) {
throw new NullPointerException("string");
}
if (split == null) {
throw new NullPointerException("split");
}
if (split.isEmpty()) {
throw new IllegalArgumentException("split must not be empty");
}
if (max <= 0) {
throw new IllegalArgumentException("max must be >= 1, was " + max);
}
return new Iterable() {
@Override
public Iterator iterator() {
return new Iterator() {
private int _count = 0;
private int _pos = 0;
@Override
public boolean hasNext() {
return _pos >= 0;
}
@Override
public String next() {
if (!hasNext()) {
throw new NoSuchElementException();
}
int next = ++_count == max ? -1 : string.indexOf(split, _pos);
String str;
if (next > 0) {
str = string.substring(_pos, next);
_pos = next + split.length();
} else {
str = string.substring(_pos);
_pos = -1;
}
return str;
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
};
}
};
}
public static String join(String separator, Object... fragments) {
return join(separator, Arrays.asList(fragments));
}
public static String join(String separator, Iterable fragments) {
return join(separator, IteratorUtils.iterator(fragments));
}
public static String join(String separator, Iterator fragments) {
if (!fragments.hasNext()) {
return "";
}
if (separator == null) {
separator = "";
}
StringBuffer buf = new StringBuffer(128);
do {
String fragment = string(fragments.next());
if (!empty(fragment)) {
buf.append(fragment).append(separator);
}
} while (fragments.hasNext());
if (buf.length() > 0) {
buf.setLength(buf.length() - separator.length());
}
return buf.toString();
}
public static String string(Object o) {
return o == null ? null : o.toString();
}
public static String padLeft(String str, char pad, int length) {
return padLeft(str, Character.toString(pad), length);
}
public static String padLeft(String str, String pad, int length) {
if (empty(str) || str.length() >= length) {
return str;
}
int padding = length - str.length();
StringBuilder buf = new StringBuilder(length);
while (buf.length() < padding) {
buf.append(pad);
}
buf.setLength(padding);
buf.append(str);
return buf.toString();
}
public static String padRight(String str, char pad, int length) {
return padRight(str, Character.toString(pad), length);
}
public static String padRight(String str, String pad, int length) {
if (empty(str) || str.length() >= length) {
return str;
}
StringBuilder buf = new StringBuilder(length);
buf.append(str);
while (buf.length() < length) {
buf.append(pad);
}
buf.setLength(length);
return buf.toString();
}
}