Name: nl37777 Date: 09/29/98


Version^[$B!'^[(J1.2fcs_K

In the following sample, an IllegalArgumentException is thrown.
So, it is not possible to look for the previous boundary from last position of the text.

    import java.text.BreakIterator;
    
    public class PrecedingTest {
        public static void main(String args[]) {
            BreakIterator boundary = BreakIterator.getCharacterInstance();
            boundary.setText("abc");
            int last = boundary.last();
            System.out.println("last " + last);
            int beforeLast = boundary.preceding(last);
            // Exception java.lang.IllegalArgumentException:
            // preceding() offset out of bounds
            System.out.println("beforeLast " + beforeLast);
        }
    }


The related source files.

src/share/classes/java/text/SimpleTextBoundary.java
src/share/classes/java/text/BreakIterator.java



In SimpleTextBoundary, the range of check of the parameter is same in following(int) and preceding(int).
But, it is not correct.

  <Current parameter check>
    following(int offset):
        offset < text.getBeginIndex() || offset >= text.getEndIndex()
    preceding(int offset):
        offset < text.getBeginIndex() || offset >= text.getEndIndex()

  <The sample of revision>
    following(int offset):
        offset < text.getBeginIndex() || offset >= text.getEndIndex()
    preceding(int offset):
        offset <= text.getBeginIndex() || offset > text.getEndIndex()



In addition, the implementation of BreakIterator.preceding(int offset) is not correct.

  <Current BreakIterator's source>
    public int preceding(int offset) {
        int pos = following(offset); // <- here
        while (pos >= offset && pos != DONE)
            pos = previous();
        return pos;
    }

  <The sample of revision>
        int pos = following(offset - 1);
(Review ID: 39425)
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