Working with Text |
You invoke thegetWordIterator
method to instantiate aBreakIterator
that detects word boundaries:You'll want to create such aBreakIterator wordIterator = BreakIterator.getWordInstance(currentLocale);BreakIterator
when your application needs to perform operations on individual words. These operations might be common word processing functions such as selecting, cutting, pasting, and copying. Or, your application may search for words, and it must be able to distinguish entire words from simple strings.When performing word boundary analysis, a
BreakIterator
differentiates between words and characters that are not part of words. These characters, which include spaces, tabs, punctuation marks, and some symbols, have word boundaries on both sides.The example that follows, which is from the program
BreakIteratorDemo.java
, marks the word boundaries in some text. The program creates theBreakIterator
and then calls themarkBoundaries
method:TheLocale currentLocale = new Locale ("en","US"); BreakIterator wordIterator = BreakIterator.getWordInstance(currentLocale); String someText = "She stopped. " + "She said, \"Hello there,\" and then went on."; markBoundaries(someText, wordIterator);markBoundaries
method is defined inBreakIteratorDemo.java
. This method marks boundaries by printing carets ('^') beneath the target string. In the code that follows, notice thewhile
loop wheremarkBoundaries
scans the string by calling thenext
method:The output of thestatic void markBoundaries(String target, BreakIterator iterator) { StringBuffer markers = new StringBuffer(); markers.setLength(target.length() + 1); for (int k = 0; k < markers.length(); k++) { markers.setCharAt(k,' '); } iterator.setText(target); int boundary = iterator.first(); while (boundary != BreakIterator.DONE) { markers.setCharAt(boundary,'^'); boundary = iterator.next(); } System.out.println(target); System.out.println(markers); }markBoundaries
method follows. Note where the carets ('^') occur in relation to the punctuation marks and spaces:TheShe stopped. She said, "Hello there," and then went on. ^ ^^ ^^ ^ ^^ ^^^^ ^^ ^^^^ ^^ ^^ ^^ ^BreakIterator
class makes it easy to select words from within text. You don't have to write your own routines to handle the punctuation rules of various languages, because theBreakIterator
class does this for you. Here is a routine that extracts and prints words for a given string:Thestatic void extractWords(String target, BreakIterator wordIterator) { wordIterator.setText(target); int start = wordIterator.first(); int end = wordIterator.next(); while (end != BreakIterator.DONE) { String word = target.substring(start,end); if (Character.isLetterOrDigit(word.charAt(0))) { System.out.println(word); } start = end; end = wordIterator.next(); } }BreakIteratorDemo
program invokesextractWords
, passing it the same target string used in the previous example. TheextractWords
method prints out the following list of words:She stopped She said Hello there and then went on.
Working with Text |