* Line boundary analysis determines where a text string can be broken * when line-wrapping. The mechanism correctly handles punctuation and * hyphenated words. *
* Sentence boundary analysis allows selection with correct * interpretation of periods within numbers and abbreviations, and * trailing punctuation marks such as quotation marks and parentheses. *
* Word boundary analysis is used by search and replace functions, as * well as within text editing applications that allow the user to * select words with a double click. Word selection provides correct * interpretation of punctuation marks within and following * words. Characters that are not part of a word, such as symbols or * punctuation marks, have word-breaks on both sides. *
* Character boundary analysis allows users to interact with * characters as they expect to, for example, when moving the cursor * through a text string. Character boundary analysis provides correct * navigation of through character strings, regardless of how the * character is stored. For example, an accented character might be * stored as a base character and a diacritical mark. What users * consider to be a character can differ between languages. *
* This is the interface for all text boundaries. *
* Examples: *
* Print each element in order: *
* . void printEachForward(const BreakIterator& boundary) {
* . UnicodeString textChunk;
* . TextOffset start = boundary.first();
* . for (TextOffset end = boundary.next();
* . end != BreakIterator::DONE;
* . start = end, end = boundary.next())
* . {
* . cout << boundary.getText()->extract(start, end, textChunk);
* . }
* . }
*
* Print each element in reverse order:
*
* . void printEachbackward(const BreakIterator& boundary) {
* . UnicodeString textChunk;
* . TextOffset end = boundary.last();
* . for (TextOffset start = boundary.previous();
* . start != BreakIterator::DONE;
* . end = start, start = boundary.previous())
* . {
* . cout << boundary.getText()->extract(start, end, textChunk);
* . }
* . }
*
*/
class T_FINDWORD_API BreakIterator {
public:
virtual ~BreakIterator();
/**
* Return true if another object is semantically equal to this
* one. The other object should be an instance of the same subclass of
* BreakIterator. Objects of different subclasses are considered
* unequal.
* * Return true if this BreakIterator is at the same position in the * same text, and is the same class and type (word, line, etc.) of * BreakIterator, as the argument. Text is considered the same if * it contains the same characters, it need not be the same * object, and styles are not considered. */ virtual t_bool operator==(const BreakIterator&) const = 0; t_bool operator!=(const BreakIterator& rhs) const { return !operator==(rhs); } /** * Return a polymorphic copy of this object. This is an abstract * method which subclasses implement. */ virtual BreakIterator* clone() const = 0; /** * Return a polymorphic class ID for this object. Different subclasses * will return distinct unequal values. */ virtual ClassID getDynamicClassID() const = 0; /** * Get the text for which this object is finding the boundaries. */ virtual const UnicodeString* getText() const = 0; /** * Set the text for which this object should find the boundaries. */ virtual void setText(const UnicodeString*) = 0; /** * DONE is returned by previous() and next() after all valid * boundaries have been returned. */ static const TextOffset DONE; /** * Return the index of the first character in the text being scanned. */ virtual TextOffset first() = 0; /** * Return the index immediately BEYOND the last character in the text being scanned. */ virtual TextOffset last() = 0; /** * Return the boundary preceding the current boundary. * @return The character index of the previous text boundary or DONE if all * boundaries have been returned. */ virtual TextOffset previous() = 0; /** * Return the boundary following the current boundary. * @return The character index of the next text boundary or DONE if all * boundaries have been returned. */ virtual TextOffset next() = 0; /** * Return character index of the text boundary that was most recently * returned by next(), previous(), first(), or last() * @return The boundary most recently returned. */ virtual TextOffset current() const = 0; /** * Return the first boundary following the specified offset. * The value returned is always greater than the offset or * the value BreakIterator.DONE * @param offset the offset to begin scanning. * @return The first boundary after the specified offset. */ virtual TextOffset following(TextOffset offset) = 0; /** * Return the nth boundary from the current boundary * @param n which boundary to return. A value of 0 * does nothing. Negative values move to previous boundaries * and positive values move to later boundaries. * @return The index of the nth boundary from the current position, or * DONE if there are fewer than |n| boundaries in the specfied direction. */ virtual TextOffset next(t_int32 n) = 0; /** * Create BreakIterator for word-breaks using the given locale. * Returns an instance of a BreakIterator implementing word breaks. * WordBreak is useful for word selection (ex. double click) * @param where the locale. If a specific WordBreak is not * avaliable for the specified locale, a default WordBreak is returned. * @return A BreakIterator for word-breaks */ static BreakIterator* createWordInstance(const Locale& where = Locale::getDefault()); /** * Create BreakIterator for line-breaks using specified locale. * Returns an instance of a BreakIterator implementing line breaks. Line * breaks are logically possible line breaks, actual line breaks are * usually determined based on display width. * LineBreak is useful for word wrapping text. * @param where the locale. If a specific LineBreak is not * avaliable for the specified locale, a default LineBreak is returned. * @return A BreakIterator for line-breaks */ static BreakIterator* createLineInstance(const Locale& where = Locale::getDefault()); /** * Create BreakIterator for character-breaks using specified locale * Returns an instance of a BreakIterator implementing character breaks. * Character breaks are boundaries of combining character sequences. * @param where the locale. If a specific character break is not * avaliable for the specified locale, a default character break is returned. * @return A BreakIterator for character-breaks */ static BreakIterator* createCharacterInstance(const Locale& where = Locale::getDefault()); /** * Create BreakIterator for sentence-breaks using specified locale * Returns an instance of a BreakIterator implementing sentence breaks. * @param where the locale. If a specific SentenceBreak is not * avaliable for the specified locale, a default SentenceBreak is returned. * @return A BreakIterator for sentence-breaks */ static BreakIterator* createSentenceInstance(const Locale& where = Locale::getDefault()); /** * Get the set of Locales for which TextBoundaries are installed * @param count the output parameter of number of elements in the locale list * @return available locales */ static const Locale* getAvailableLocales(t_int32& count); /** * Get name of the object for the desired Locale, in the desired langauge. * @param objectLocale must be from getAvailableLocales. * @param displayLocale specifies the desired locale for output. * @param name the fill-in parameter of the return value * Uses best match. * @return user-displayable name */ static UnicodeString& getDisplayName(const Locale& objectLocale, const Locale& displayLocale, UnicodeString& name); /** * Get name of the object for the desired Locale, in the langauge of the * default locale. * @param objectLocale must be from getMatchingLocales * @param name the fill-in parameter of the return value * @return user-displayable name */ static UnicodeString& getDisplayName(const Locale& objectLocale, UnicodeString& name); // begin deprecated api. virtual TextOffset nextAfter(TextOffset offset) = 0; virtual TextOffset nthFromCurrent(t_int32 n) = 0; static BreakIterator* createWordBreak(const Locale& where = Locale::getDefault()) { return createWordInstance(); } static BreakIterator* createLineBreak(const Locale& where = Locale::getDefault()) { return createLineInstance(); } static BreakIterator* createCharacterBreak(const Locale& where = Locale::getDefault()) { return createCharacterInstance(); } static BreakIterator* createSentenceBreak(const Locale& where = Locale::getDefault()) { return createSentenceInstance(); } // end deprecated api. protected: BreakIterator(); private: /** * The copy constructor and assignment operator have no real implementation. * They are provided to make the compiler happy. Do not call. */ BreakIterator& operator=(const BreakIterator& other) { return *this; } BreakIterator (const BreakIterator& other) {} }; #endif // _BRKITER //eof