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package com.sun.xml.bind;
/**
* Processes white space normalization.
*
* @since 1.0
*/
public abstract class WhiteSpaceProcessor {
// benchmarking (see test/src/ReplaceTest.java in the CVS Attic)
// showed that this code is slower than the current code.
//
// public static String replace(String text) {
// final int len = text.length();
// StringBuffer result = new StringBuffer(len);
//
// for (int i = 0; i < len; i++) {
// char ch = text.charAt(i);
// if (isWhiteSpace(ch))
// result.append(' ');
// else
// result.append(ch);
// }
//
// return result.toString();
// }
public static String replace(String text) {
return replace( (CharSequence)text ).toString();
}
/**
* @since 2.0
*/
public static CharSequence replace(CharSequence text) {
int i=text.length()-1;
// look for the first whitespace char.
while( i>=0 && !isWhiteSpaceExceptSpace(text.charAt(i)) )
i--;
if( i<0 )
// no such whitespace. replace(text)==text.
return text;
// we now know that we need to modify the text.
// allocate a char array to do it.
StringBuilder buf = new StringBuilder(text);
buf.setCharAt(i--,' ');
for( ; i>=0; i-- )
if( isWhiteSpaceExceptSpace(buf.charAt(i)))
buf.setCharAt(i,' ');
return new String(buf);
}
/**
* Equivalent of {@link String#trim()}.
* @since 2.0
*/
public static CharSequence trim(CharSequence text) {
int len = text.length();
int start = 0;
while( start<len && isWhiteSpace(text.charAt(start)) )
start++;
int end = len-1;
while( end>start && isWhiteSpace(text.charAt(end)) )
end--;
if(start==0 && end==len-1)
return text; // no change
else
return text.subSequence(start,end+1);
}
public static String collapse(String text) {
return collapse( (CharSequence)text ).toString();
}
/**
* This is usually the biggest processing bottleneck.
*
* @since 2.0
*/
public static CharSequence collapse(CharSequence text) {
int len = text.length();
// most of the texts are already in the collapsed form.
// so look for the first whitespace in the hope that we will
// never see it.
int s=0;
while(s<len) {
if(isWhiteSpace(text.charAt(s)))
break;
s++;
}
if(s==len)
// the input happens to be already collapsed.
return text;
// we now know that the input contains spaces.
// let's sit down and do the collapsing normally.
StringBuilder result = new StringBuilder(len /*allocate enough size to avoid re-allocation*/ );
if(s!=0) {
for( int i=0; i<s; i++ )
result.append(text.charAt(i));
result.append(' ');
}
boolean inStripMode = true;
for (int i = s+1; i < len; i++) {
char ch = text.charAt(i);
boolean b = isWhiteSpace(ch);
if (inStripMode && b)
continue; // skip this character
inStripMode = b;
if (inStripMode)
result.append(' ');
else
result.append(ch);
}
// remove trailing whitespaces
len = result.length();
if (len > 0 && result.charAt(len - 1) == ' ')
result.setLength(len - 1);
// whitespaces are already collapsed,
// so all we have to do is to remove the last one character
// if it's a whitespace.
return result;
}
/**
* Returns true if the specified string is all whitespace.
*/
public static boolean isWhiteSpace(CharSequence s) {
for( int i=s.length()-1; i>=0; i-- )
if(!isWhiteSpace(s.charAt(i)))
return false;
return true;
}
/** returns true if the specified char is a white space character. */
public static boolean isWhiteSpace(char ch) {
// most of the characters are non-control characters.
// so check that first to quickly return false for most of the cases.
if( ch>0x20 ) return false;
// other than we have to do four comparisons.
return ch == 0x9 || ch == 0xA || ch == 0xD || ch == 0x20;
}
/**
* Returns true if the specified char is a white space character
* but not 0x20.
*/
protected static boolean isWhiteSpaceExceptSpace(char ch) {
// most of the characters are non-control characters.
// so check that first to quickly return false for most of the cases.
if( ch>=0x20 ) return false;
// other than we have to do four comparisons.
return ch == 0x9 || ch == 0xA || ch == 0xD;
}
}