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BreakIterator that has been created with the
getLineInstance method:
BreakIterator lineIterator = BreakIterator.getLineInstance(currentLocale);
This BreakIterator
determines the positions in a string where text can break to continue
on the next line. The positions detected by the
BreakIterator are potential line breaks. The actual line
breaks displayed on the screen may not be the same.
The two examples that follow use the
markBoundaries
method of
BreakIteratorDemo.java
to show the line boundaries detected by a BreakIterator.
The markBoundaries method indicates line boundaries by
printing carets (^) beneath the target string.
According to a BreakIterator, a line boundary occurs after
the termination of a sequence of whitespace characters (space, tab, new
line). In the following example, note that you can break the line at
any of the boundaries detected:
She stopped. She said, "Hello there," and then went on. ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
Potential line breaks also occur immediately after a hyphen:
There are twenty-four hours in a day. ^ ^ ^ ^ ^ ^ ^ ^ ^
The next example breaks a long string of text into fixed-length lines
with a method called formatLines. This method uses a
BreakIterator to locate the potential line breaks. The
formatLines method is short, simple, and, thanks to the
BreakIterator, locale-independent. Here is the source
code:
static void formatLines(String target, int maxLength,
Locale currentLocale) {
BreakIterator boundary =
BreakIterator.getLineInstance(currentLocale);
boundary.setText(target);
int start = boundary.first();
int end = boundary.next();
int lineLength = 0;
while (end != BreakIterator.DONE) {
String word = target.substring(start,end);
lineLength = lineLength + word.length();
if (lineLength >= maxLength) {
System.out.println();
lineLength = word.length();
}
System.out.print(word);
start = end;
end = boundary.next();
}
}
The BreakIteratorDemo program invokes the formatLines
method as follows:
String moreText = "She said, \"Hello there,\" and then " + "went on down the street. When she stopped " + "to look at the fur coats in a shop window, " + "her dog growled._ \"Sorry Jake,\" she said. " + " \"I didn't know you would take it personally.\""; formatLines(moreText, 30, currentLocale);
The output from this call to formatLines is:
She said, "Hello there," and then went on down the street. When she stopped to look at the fur coats in a shop window, her dog growled. "Sorry Jake," she said. "I didn't know you would take it personally."
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