net.sf.jett.parser.StyleScanner Maven / Gradle / Ivy
package net.sf.jett.parser;
/**
* A StyleScanner scans CSS text and returns tokens.
*
* @author Randy Gettman
* @since 0.5.0
*/
public class StyleScanner
{
/**
* Enumeration for the different types of Tokens in "CSS".
*/
public enum Token
{
TOKEN_ERROR_EOI_IN_COMMENT(-3),
TOKEN_ERROR_BUF_NULL(-2),
TOKEN_UNKNOWN(-1),
TOKEN_WHITESPACE(0),
TOKEN_STRING(1),
TOKEN_COLON(11),
TOKEN_PERIOD(12),
TOKEN_BEGIN_BRACE(13),
TOKEN_END_BRACE(14),
TOKEN_SEMICOLON(15),
TOKEN_COMMENT(98),
TOKEN_EOI(99);
private int myCode;
// Create a token with a code.
private Token(int code)
{
myCode = code;
}
/**
* Returns the unique code associated with this Token.
* @return The unique code.
*/
public int getCode()
{
return myCode;
}
}
private static final String PUNCT_CHARS_NOT_AS_STRING = ":.{};/*";
private String myCssText;
private int myOffset;
private String myCurrLexeme;
/**
* Construct a StyleScanner object, with empty input.
*/
public StyleScanner()
{
this("");
}
/**
* Construct a StyleScanner object, with the given input.
* @param cssText The CSS text to scan.
*/
public StyleScanner(String cssText)
{
setCssText(cssText);
}
/**
* Returns the Token. After this call completes, the current
* lexeme is available via a call to getCurrLexeme.
* Starts looking at the current offset, and once the token is found, then
* the offset is advanced to the start of the next token.
* @return A Token.
* @see #getCurrLexeme
*/
public Token getNextToken()
{
int iStartOfToken = myOffset;
int iTokenLength = 0;
Token tokenType = Token.TOKEN_UNKNOWN;
// EOI test.
if (iStartOfToken >= myCssText.length())
{
// End of input string.
return Token.TOKEN_EOI;
}
if (myCssText.charAt(iStartOfToken) == '/' &&
(iStartOfToken + 1) < myCssText.length() && myCssText.charAt(iStartOfToken + 1) == '*')
{
// Comment.
// Skip everything until "*/" found, or error if not found.
iTokenLength += 2;
boolean endOfCommentFound = false;
while ((iStartOfToken + iTokenLength) < myCssText.length())
{
if (myCssText.charAt(iStartOfToken + iTokenLength) == '*' &&
(iStartOfToken + iTokenLength + 1 < myCssText.length()) && myCssText.charAt(iStartOfToken + iTokenLength + 1) == '/')
{
iTokenLength += 2;
endOfCommentFound = true;
break;
}
iTokenLength++;
}
if (!endOfCommentFound)
{
myCurrLexeme = null;
return Token.TOKEN_ERROR_EOI_IN_COMMENT;
}
myOffset += iTokenLength;
iStartOfToken = myOffset;
iTokenLength = 0;
}
// First char starts a string consisting of letters, numbers, and
// all but a few punctuation characters.
if ((iStartOfToken + iTokenLength) < myCssText.length() &&
!Character.isWhitespace(myCssText.charAt(iStartOfToken + iTokenLength)) &&
PUNCT_CHARS_NOT_AS_STRING.indexOf(myCssText.charAt(iStartOfToken + iTokenLength)) == -1)
{
// String mode.
while ((iStartOfToken + iTokenLength) < myCssText.length() &&
!Character.isWhitespace(myCssText.charAt(iStartOfToken + iTokenLength)) &&
PUNCT_CHARS_NOT_AS_STRING.indexOf(myCssText.charAt(iStartOfToken + iTokenLength)) == -1)
{
iTokenLength++;
}
tokenType = Token.TOKEN_STRING;
}
else if (myCssText.charAt(iStartOfToken) == ':')
{
// Colon.
iTokenLength = 1;
tokenType = Token.TOKEN_COLON;
}
else if (myCssText.charAt(iStartOfToken) == '.')
{
// Period.
iTokenLength = 1;
tokenType = Token.TOKEN_PERIOD;
}
else if (myCssText.charAt(iStartOfToken) == '}')
{
// End brace.
iTokenLength = 1;
tokenType = Token.TOKEN_END_BRACE;
}
else if (myCssText.charAt(iStartOfToken) == '{')
{
// Begin brace.
iTokenLength = 1;
tokenType = Token.TOKEN_BEGIN_BRACE;
}
else if (myCssText.charAt(iStartOfToken) == ';')
{
// Semicolon.
iTokenLength = 1;
tokenType = Token.TOKEN_SEMICOLON;
}
else if (Character.isWhitespace(myCssText.charAt(iStartOfToken)))
{
// Whitespace.
while ((iStartOfToken + iTokenLength) < myCssText.length() &&
Character.isWhitespace(myCssText.charAt(iStartOfToken + iTokenLength)))
iTokenLength++;
tokenType = Token.TOKEN_WHITESPACE;
}
// Note down lexeme for access later.
myCurrLexeme = myCssText.substring(iStartOfToken, iStartOfToken + iTokenLength);
// Update the offset.
myOffset += iTokenLength;
return tokenType;
}
/**
* Returns the current lexeme after a call to getNextToken.
* @return The current lexeme, or null if
* getNextToken hasn't been called yet after a reset.
* @see #getNextToken
* @see #reset
*/
public String getCurrLexeme()
{
return myCurrLexeme;
}
/**
* Returns the current position of the next token.
* @return The current position of the next token.
*/
public int getNextPosition()
{
return myOffset;
}
/**
* Resets the scanner to the beginning of the CSS text.
*/
public void reset()
{
myOffset = 0;
myCurrLexeme = null;
}
/**
* Give the StyleScanner another CSS text to scan.
* Resets to the beginning of the string.
* @param cssText The css Text to scan.
*/
public void setCssText(String cssText)
{
myCssText = cssText;
reset();
}
}