codeviewer.java

这是学习Java必须读懂两套源代码

        //of a multi-line comment is in this line.
        else if ((index = line.indexOf("/*")) > -1 && !isInsideString(line,index)) {
            inMultiLineComment = true;
            //Return result of other filters + everything after the start
            //of the multiline comment. We need to pass the through the
            //to the multiLineComment filter again in case the comment ends
            //on the same line.
            buf.append(inlineCommentFilter(line.substring(0,index)));
            buf.append(commentStart).append("/*");
            buf.append(multiLineCommentFilter(line.substring(index+2)));
            return buf.toString();
        }
        //Otherwise, no useful multi-line comment information was found so
        //pass the line down to the next filter for processesing.
        else {
            return inlineCommentFilter(line);
        }
    }

    /*
     * Filter inline comments from a line and formats them properly.
     */
    private String inlineCommentFilter(String line) {
        if (line == null || line.equals("")) {
            return "";
        }
        StringBuffer buf = new StringBuffer();
        int index;
        if ((index = line.indexOf("//")) > -1 && !isInsideString(line,index)) {
            buf.append(stringFilter(line.substring(0,index)));
            buf.append(commentStart);
            buf.append(line.substring(index));
            buf.append(commentEnd);
        }
        else {
            buf.append(stringFilter(line));
        }
        return buf.toString();
    }

    /*
     * Filters strings from a line of text and formats them properly.
     */
    private String stringFilter(String line) {
        if (line == null || line.equals("")) {
            return "";
        }
        StringBuffer buf = new StringBuffer();
        if (line.indexOf("\"") <= -1) {
            return keywordFilter(line);
        }
        int start = 0;
        int startStringIndex = -1;
        int endStringIndex = -1;
        int tempIndex;
        //Keep moving through String characters until we want to stop...
        while ((tempIndex = line.indexOf("\"")) > -1) {
            //We found the beginning of a string
            if (startStringIndex == -1) {
                startStringIndex = 0;
                buf.append( stringFilter(line.substring(start,tempIndex)) );
                buf.append(stringStart).append("\"");
                line = line.substring(tempIndex+1);
            }
            //Must be at the end
            else {
                startStringIndex = -1;
                endStringIndex = tempIndex;
                buf.append(line.substring(0,endStringIndex+1));
                buf.append(stringEnd);
                line = line.substring(endStringIndex+1);
            }
        }
        buf.append( keywordFilter(line) );
        return buf.toString();
    }

    /*
     * Filters keywords from a line of text and formats them properly.
     */
    private String keywordFilter( String line ) {
        if( line == null || line.equals("") ) {
            return "";
        }
        StringBuffer buf = new StringBuffer();
        //HashMap usedReservedWords = new HashMap(); // >= Java2 only (not thread-safe)
        Hashtable usedReservedWords = new Hashtable(); // < Java2 (thread-safe)
        int i=0, startAt=0;
        char ch;
        StringBuffer temp = new StringBuffer();
        while( i < line.length() ) {
            temp.setLength(0);
            ch = line.charAt(i);
            startAt = i;
            // 65-90, uppercase letters
            // 97-122, lowercase letters
            while( i<line.length() && ( ( ch >= 65 && ch <= 90 )
                    || ( ch >= 97 && ch <= 122 ) ) ) {
                temp.append(ch);
                i++;
                if( i < line.length() ) {
                    ch = line.charAt(i);
                }
            }
            String tempString = temp.toString();
            if( reservedWords.containsKey(tempString) && !usedReservedWords.containsKey(tempString)) {
                usedReservedWords.put(tempString,tempString);
                line = replace( line, tempString, (reservedWordStart+tempString+reservedWordEnd) );
                i += (reservedWordStart.length() + reservedWordEnd.length());
            }
            else {
                i++;
            }
        }
        buf.append(line);
        return buf.toString();
    }

    /**
     * Replaces all instances of oldString with newString in line.
     */
    public static final String replace( String line, String oldString, String newString )
    {
        int i=0;
        if ( ( i=line.indexOf( oldString, i ) ) >= 0 ) {
            char [] line2 = line.toCharArray();
            char [] newString2 = newString.toCharArray();
            int oLength = oldString.length();
            StringBuffer buf = new StringBuffer(line2.length);
            buf.append(line2, 0, i).append(newString2);
            i += oLength;
            int j = i;
            while( ( i=line.indexOf( oldString, i ) ) > 0 ) {
                buf.append(line2, j, i-j).append(newString2);
                i += oLength;
                j = i;
            }
            buf.append(line2, j, line2.length - j);
            return buf.toString();
        }
        return line;
    }

    /*
     * Checks to see if some position in a line is between String start and
     * ending characters. Not yet used in code or fully working :)
     */
    private boolean isInsideString(String line, int position) {
        if (line.indexOf("\"") < 0) {
            return false;
        }
        int index;
        String left = line.substring(0,position);
        String right = line.substring(position);
        int leftCount = 0;
        int rightCount = 0;
        while ((index = left.indexOf("\"")) > -1) {
            leftCount ++;
            left = left.substring(index+1);
        }
        while ((index = right.indexOf("\"")) > -1) {
            rightCount ++;
            right = right.substring(index+1);
        }
        if (rightCount % 2 != 0 && leftCount % 2 != 0) {
            return true;
        }
        else {
            return false;
        }
    }

    /*
     * Load Hashtable (or HashMap) with Java reserved words. Improved list
     * in version 1.1 taken directly from Java language spec.
     */
    private static void loadKeywords() {
        reservedWords.put( "abstract", "abstract" );
        reservedWords.put( "boolean", "boolean" );
        reservedWords.put( "break", "break" );
        reservedWords.put( "byte", "byte" );
        reservedWords.put( "case", "case" );
        reservedWords.put( "catch", "catch" );
        reservedWords.put( "char", "char" );
        reservedWords.put( "class", "class" );
        reservedWords.put( "const", "const" );
        reservedWords.put( "continue", "continue" );
        reservedWords.put( "default", "default" );
        reservedWords.put( "do", "do" );
        reservedWords.put( "double", "double" );
        reservedWords.put( "else", "else" );
        reservedWords.put( "extends", "extends" );
        reservedWords.put( "final", "final" );
        reservedWords.put( "finally", "finally" );
        reservedWords.put( "float", "float" );
        reservedWords.put( "for", "for" );
        reservedWords.put( "goto", "goto" );
        reservedWords.put( "if", "if" );
        reservedWords.put( "implements", "implements" );
        reservedWords.put( "import", "import" );
        reservedWords.put( "instanceof", "instanceof" );
        reservedWords.put( "int", "int" );
        reservedWords.put( "interface", "interface" );
        reservedWords.put( "long", "long" );
        reservedWords.put( "native", "native" );
        reservedWords.put( "new", "new" );
        reservedWords.put( "package", "package" );
        reservedWords.put( "private", "private" );
        reservedWords.put( "protected", "protected" );
        reservedWords.put( "public", "public" );
        reservedWords.put( "return", "return" );
        reservedWords.put( "short", "short" );
        reservedWords.put( "static", "static" );
        reservedWords.put( "strictfp", "strictfp" );
        reservedWords.put( "super", "super" );
        reservedWords.put( "switch", "switch" );
        reservedWords.put( "synchronized", "synchronized" );
        reservedWords.put( "this", "this" );
        reservedWords.put( "throw", "throw" );
        reservedWords.put( "throws", "throws" );
        reservedWords.put( "transient", "transient" );
        reservedWords.put( "try", "try" );
        reservedWords.put( "void", "void" );
        reservedWords.put( "volatile", "volatile" );
        reservedWords.put( "while", "while" );
    }
}