hlapidez/anhquan

Automatically exported from code.google.com/p/anhquan

anhquan's Issues

BufferedReader reading blank line should produce "" instead of null

What steps will reproduce the problem?
1. Reader reader = new StringReader("  \n\n \n size\n 30   40 ");
2. Scanner scanner = new Scanner(reader);
3. scanner.next();
4. System.out.println(scanner.next());

What is the expected output? What do you see instead?
Should output empty string "";
Actually prints null.
This is a problem because aside from being a little counter-intuitive, the 
behavior differs from the standard java.io library behavior and breaks 
compatibility with scanners and such.

The source code of BufferedReader.readLine() is:

    /**
     * Reads the next line of characters.
     * 
     * @return The next line.
     */
    public String readLine() throws IOException {
    StringBuilder sb = null;
    boolean eol = false;
    int nextChar = read();

    while (!eol && (nextChar != -1)) {
        if (nextChar == 10) {
        eol = true;
        } else if (nextChar == 13) {
        eol = true;

        // Check if there is a immediate LF following the CR
        nextChar = read();
        if (nextChar != 10) {
            this.savedNextChar = nextChar;
        }
        }

        if (!eol) {
        if (sb == null) {
            sb = new StringBuilder();
        }

        sb.append((char) nextChar);
        nextChar = read();
        }

    }
    return (sb == null) ? null : sb.toString();
    }


I believe you can fix the problem by replacing the last return statement with:
    if (sb == null) {
        if(nextChar != -1){
        return "";
        }
        return null;
    }
    return sb.toString();

Also, thanks for the useful lib. Some form of java.io should really be included 
in gwt because it's used very frequently and makes porting things to gwt a real 
pain if you don't have this library.

Original issue reported on code.google.com by [email protected] on 4 May 2012 at 10:56