org.apache.axis.utils.StringUtils Maven / Gradle / Ivy
/*
* Copyright 2001-2004 The Apache Software Foundation.
*
* 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 org.apache.axis.utils;
import org.apache.axis.InternalException;
import java.util.ArrayList;
import java.util.List;
import java.io.Writer;
import java.io.IOException;
import java.io.StringWriter;
public class StringUtils {
private StringUtils() {
}
/**
* An empty immutable String array.
*/
public static final String[] EMPTY_STRING_ARRAY = new String[0];
/**
* Tests if this string starts with the specified prefix (Ignoring whitespaces)
* @param prefix
* @param string
* @return boolean
*/
public static boolean startsWithIgnoreWhitespaces(String prefix, String string) {
int index1 = 0;
int index2 = 0;
int length1 = prefix.length();
int length2 = string.length();
char ch1 = ' ';
char ch2 = ' ';
while (index1 < length1 && index2 < length2) {
while (index1 < length1 && Character.isWhitespace(ch1 = prefix.charAt(index1))) {
index1++;
}
while (index2 < length2 && Character.isWhitespace(ch2 = string.charAt(index2))) {
index2++;
}
if (index1 == length1 && index2 == length2) {
return true;
}
if (ch1 != ch2) {
return false;
}
index1++;
index2++;
}
if(index1 < length1 && index2 >= length2)
return false;
return true;
}
/**
* Splits the provided text into an array, separator specified.
* This is an alternative to using StringTokenizer.
*
* The separator is not included in the returned String array.
* Adjacent separators are treated as one separator.
*
* A null input String returns null.
*
*
* StringUtils.split(null, *) = null
* StringUtils.split("", *) = []
* StringUtils.split("a.b.c", '.') = ["a", "b", "c"]
* StringUtils.split("a..b.c", '.') = ["a", "b", "c"]
* StringUtils.split("a:b:c", '.') = ["a:b:c"]
* StringUtils.split("a\tb\nc", null) = ["a", "b", "c"]
* StringUtils.split("a b c", ' ') = ["a", "b", "c"]
*
*
* @param str the String to parse, may be null
* @param separatorChar the character used as the delimiter,
* null splits on whitespace
* @return an array of parsed Strings, null if null String input
*/
public static String[] split(String str, char separatorChar) {
if (str == null) {
return null;
}
int len = str.length();
if (len == 0) {
return EMPTY_STRING_ARRAY;
}
List list = new ArrayList();
int i = 0, start = 0;
boolean match = false;
while (i < len) {
if (str.charAt(i) == separatorChar) {
if (match) {
list.add(str.substring(start, i));
match = false;
}
start = ++i;
continue;
}
match = true;
i++;
}
if (match) {
list.add(str.substring(start, i));
}
return (String[]) list.toArray(new String[list.size()]);
}
// Empty checks
//-----------------------------------------------------------------------
/**
* Checks if a String is empty ("") or null.
*
*
* StringUtils.isEmpty(null) = true
* StringUtils.isEmpty("") = true
* StringUtils.isEmpty(" ") = false
* StringUtils.isEmpty("bob") = false
* StringUtils.isEmpty(" bob ") = false
*
*
* NOTE: This method changed in Lang version 2.0.
* It no longer trims the String.
* That functionality is available in isBlank().
*
* @param str the String to check, may be null
* @return true if the String is empty or null
*/
public static boolean isEmpty(String str) {
return (str == null || str.length() == 0);
}
// Stripping
//-----------------------------------------------------------------------
/**
* Strips whitespace from the start and end of a String.
*
* This removes whitespace. Whitespace is defined by
* {@link Character#isWhitespace(char)}.
*
* A null input String returns null.
*
*
* StringUtils.strip(null) = null
* StringUtils.strip("") = ""
* StringUtils.strip(" ") = ""
* StringUtils.strip("abc") = "abc"
* StringUtils.strip(" abc") = "abc"
* StringUtils.strip("abc ") = "abc"
* StringUtils.strip(" abc ") = "abc"
* StringUtils.strip(" ab c ") = "ab c"
*
*
* @param str the String to remove whitespace from, may be null
* @return the stripped String, null if null String input
*/
public static String strip(String str) {
return strip(str, null);
}
/**
* Strips any of a set of characters from the start and end of a String.
* This is similar to {@link String#trim()} but allows the characters
* to be stripped to be controlled.
*
* A null input String returns null.
* An empty string ("") input returns the empty string.
*
* If the stripChars String is null, whitespace is
* stripped as defined by {@link Character#isWhitespace(char)}.
* Alternatively use {@link #strip(String)}.
*
*
* StringUtils.strip(null, *) = null
* StringUtils.strip("", *) = ""
* StringUtils.strip("abc", null) = "abc"
* StringUtils.strip(" abc", null) = "abc"
* StringUtils.strip("abc ", null) = "abc"
* StringUtils.strip(" abc ", null) = "abc"
* StringUtils.strip(" abcyx", "xyz") = " abc"
*
*
* @param str the String to remove characters from, may be null
* @param stripChars the characters to remove, null treated as whitespace
* @return the stripped String, null if null String input
*/
public static String strip(String str, String stripChars) {
if (str == null) {
return str;
}
int len = str.length();
if (len == 0) {
return str;
}
int start = getStripStart(str, stripChars);
if (start == len) {
return "";
}
int end = getStripEnd(str, stripChars);
return (start == 0 && end == len) ? str : str.substring(start, end);
}
/**
* Strips any of a set of characters from the start of a String.
*
* A null input String returns null.
* An empty string ("") input returns the empty string.
*
* If the stripChars String is null, whitespace is
* stripped as defined by {@link Character#isWhitespace(char)}.
*
*
* StringUtils.stripStart(null, *) = null
* StringUtils.stripStart("", *) = ""
* StringUtils.stripStart("abc", "") = "abc"
* StringUtils.stripStart("abc", null) = "abc"
* StringUtils.stripStart(" abc", null) = "abc"
* StringUtils.stripStart("abc ", null) = "abc "
* StringUtils.stripStart(" abc ", null) = "abc "
* StringUtils.stripStart("yxabc ", "xyz") = "abc "
*
*
* @param str the String to remove characters from, may be null
* @param stripChars the characters to remove, null treated as whitespace
* @return the stripped String, null if null String input
*/
public static String stripStart(String str, String stripChars) {
int start = getStripStart(str, stripChars);
return (start <= 0) ? str : str.substring(start);
}
private static int getStripStart(String str, String stripChars) {
int strLen;
if (str == null || (strLen = str.length()) == 0) {
return -1;
}
int start = 0;
if (stripChars == null) {
while ((start != strLen) && Character.isWhitespace(str.charAt(start))) {
start++;
}
} else if (stripChars.length() == 0) {
return start;
} else {
while ((start != strLen) && (stripChars.indexOf(str.charAt(start)) != -1)) {
start++;
}
}
return start;
}
/**
* Strips any of a set of characters from the end of a String.
*
* A null input String returns null.
* An empty string ("") input returns the empty string.
*
* If the stripChars String is null, whitespace is
* stripped as defined by {@link Character#isWhitespace(char)}.
*
*
* StringUtils.stripEnd(null, *) = null
* StringUtils.stripEnd("", *) = ""
* StringUtils.stripEnd("abc", "") = "abc"
* StringUtils.stripEnd("abc", null) = "abc"
* StringUtils.stripEnd(" abc", null) = " abc"
* StringUtils.stripEnd("abc ", null) = "abc"
* StringUtils.stripEnd(" abc ", null) = " abc"
* StringUtils.stripEnd(" abcyx", "xyz") = " abc"
*
*
* @param str the String to remove characters from, may be null
* @param stripChars the characters to remove, null treated as whitespace
* @return the stripped String, null if null String input
*/
public static String stripEnd(String str, String stripChars) {
int end = getStripEnd(str, stripChars);
return (end < 0) ? str : str.substring(0, end);
}
private static int getStripEnd(String str, String stripChars) {
int end;
if (str == null || (end = str.length()) == 0) {
return -1;
}
if (stripChars == null) {
while ((end != 0) && Character.isWhitespace(str.charAt(end - 1))) {
end--;
}
} else if (stripChars.length() == 0) {
return end;
} else {
while ((end != 0) && (stripChars.indexOf(str.charAt(end - 1)) != -1)) {
end--;
}
}
return end;
}
/**
* write the escaped version of a given string
*
* @param str string to be encoded
* @return a new escaped String, null if null string input
*/
public static String escapeNumericChar(String str) {
if (str == null) {
return null;
}
try {
StringWriter writer = new StringWriter(str.length());
escapeNumericChar(writer, str);
return writer.toString();
} catch (IOException ioe) {
// this should never ever happen while writing to a StringWriter
ioe.printStackTrace();
return null;
}
}
/**
* write the escaped version of a given string
*
* @param out writer to write this string to
* @param str string to be encoded
*/
public static void escapeNumericChar(Writer out, String str)
throws IOException {
if (str == null) {
return;
}
int length = str.length();
char character;
for (int i = 0; i < length; i++) {
character = str.charAt( i );
if (character > 0x7F) {
out.write("&#x");
out.write(Integer.toHexString(character).toUpperCase());
out.write(";");
} else {
out.write(character);
}
}
}
/**
* Unescapes numeric character referencs found in the String.
*
* For example, it will return a unicode string which means the specified numeric
* character references looks like "ようこそ".
*
* @param str the String to unescape, may be null
* @return a new unescaped String, null if null string input
*/
public static String unescapeNumericChar(String str) {
if (str == null) {
return null;
}
try {
StringWriter writer = new StringWriter(str.length());
unescapeNumericChar(writer, str);
return writer.toString();
} catch (IOException ioe) {
// this should never ever happen while writing to a StringWriter
ioe.printStackTrace();
return null;
}
}
/**
* Unescapes numeric character references found in the String to a
* Writer.
*
* For example, it will return a unicode string which means the specified numeric
* character references looks like "ようこそ".
*
* A null string input has no effect.
*
* @param out the Writer used to output unescaped characters
* @param str the String to unescape, may be null
* @throws IllegalArgumentException if the Writer is null
* @throws java.io.IOException if error occurs on underlying Writer
*/
public static void unescapeNumericChar(Writer out, String str) throws IOException {
if (out == null) {
throw new IllegalArgumentException("The Writer must not be null");
}
if (str == null) {
return;
}
int sz = str.length();
StringBuffer unicode = new StringBuffer(4);
StringBuffer escapes = new StringBuffer(3);
boolean inUnicode = false;
for (int i = 0; i < sz; i++) {
char ch = str.charAt(i);
if (inUnicode) {
// if in unicode, then we're reading unicode
// values in somehow
unicode.append(ch);
if (unicode.length() == 4) {
// unicode now contains the four hex digits
// which represents our unicode character
try {
int value = Integer.parseInt(unicode.toString(), 16);
out.write((char) value);
unicode.setLength(0);
// need to skip the delimiter - ';'
i = i + 1;
inUnicode = false;
} catch (NumberFormatException nfe) {
throw new InternalException(nfe);
}
}
continue;
} else if (ch=='&') {
// Start of the escape sequence ...
// At least, the numeric character references require 8 bytes to
// describe a Unicode character like as""
if (i+7 <= sz) {
escapes.append(ch);
escapes.append(str.charAt(i+1));
escapes.append(str.charAt(i+2));
if (escapes.toString().equals("&#x") && str.charAt(i+7)==';') {
inUnicode = true;
} else {
out.write(escapes.toString());
}
escapes.setLength(0);
// need to skip the escaping chars - '&#x'
i = i + 2;
} else {
out.write(ch);
}
continue;
}
out.write(ch);
}
}
}