java.text.CharacterIterator#setIndex ( )源码实例Demo

/**
 * Advances the iterator one step backwards.
 * @return The position of the last boundary position before the
 * current iteration position
 */
@Override
public int previous() {
    CharacterIterator text = getText();

    // if we have cached break positions and we're still in the range
    // covered by them, just move one step backward in the cache
    if (cachedBreakPositions != null && positionInCache > 0) {
        --positionInCache;
        text.setIndex(cachedBreakPositions[positionInCache]);
        return cachedBreakPositions[positionInCache];
    }

    // otherwise, dump the cache and use the inherited previous() method to move
    // backward.  This may fill up the cache with new break positions, in which
    // case we have to mark our position in the cache
    else {
        cachedBreakPositions = null;
        int result = super.previous();
        if (cachedBreakPositions != null) {
            positionInCache = cachedBreakPositions.length - 2;
        }
        return result;
    }
}
 

/**
 *
 * @return -1 if <var>iterator</var> does not contain this pattern.
 */
public int matches(CharacterIterator iterator, int start, int limit) {
    if (this.ignoreCase)  return this.matchesIgnoreCase(iterator, start, limit);
    int plength = this.pattern.length;
    if (plength == 0)  return start;
    int index = start+plength;
    while (index <= limit) {
        int pindex = plength;
        int nindex = index+1;
        char ch;
        do {
            if ((ch = iterator.setIndex(--index)) != this.pattern[--pindex])
                break;
            if (pindex == 0)
                return index;
        } while (pindex > 0);
        index += this.shiftTable[ch % this.shiftTable.length]+1;
        if (index < nindex)  index = nindex;
    }
    return -1;
}
 

/**
 * Advances the iterator one step backwards.
 * @return The position of the last boundary position before the
 * current iteration position
 */
@Override
public int previous() {
    CharacterIterator text = getText();

    // if we have cached break positions and we're still in the range
    // covered by them, just move one step backward in the cache
    if (cachedBreakPositions != null && positionInCache > 0) {
        --positionInCache;
        text.setIndex(cachedBreakPositions[positionInCache]);
        return cachedBreakPositions[positionInCache];
    }

    // otherwise, dump the cache and use the inherited previous() method to move
    // backward.  This may fill up the cache with new break positions, in which
    // case we have to mark our position in the cache
    else {
        cachedBreakPositions = null;
        int result = super.previous();
        if (cachedBreakPositions != null) {
            positionInCache = cachedBreakPositions.length - 2;
        }
        return result;
    }
}
 

/**
 * Set the iterator to analyze a new piece of text.  This function resets
 * the current iteration position to the beginning of the text.
 * @param newText An iterator over the text to analyze.
 */
@Override
public void setText(CharacterIterator newText) {
    // Test iterator to see if we need to wrap it in a SafeCharIterator.
    // The correct behavior for CharacterIterators is to allow the
    // position to be set to the endpoint of the iterator.  Many
    // CharacterIterators do not uphold this, so this is a workaround
    // to permit them to use this class.
    int end = newText.getEndIndex();
    boolean goodIterator;
    try {
        newText.setIndex(end);  // some buggy iterators throw an exception here
        goodIterator = newText.getIndex() == end;
    }
    catch(IllegalArgumentException e) {
        goodIterator = false;
    }

    if (goodIterator) {
        text = newText;
    }
    else {
        text = new SafeCharIterator(newText);
    }
    text.first();

    cachedLastKnownBreak = BreakIterator.DONE;
}
 

@Override
public int findBreaks(CharacterIterator text, int startPos, int endPos,
        int breakType, DequeI foundBreaks) {
    int result = 0;

     // Find the span of characters included in the set.
     //   The span to break begins at the current position int the text, and
     //   extends towards the start or end of the text, depending on 'reverse'.

    int start = text.getIndex();
    int current;
    int rangeStart;
    int rangeEnd;
    int c = CharacterIteration.current32(text);
    while ((current = text.getIndex()) < endPos && fSet.contains(c)) {
        CharacterIteration.next32(text);
        c = CharacterIteration.current32(text);
    }
    rangeStart = start;
    rangeEnd = current;

    // if (breakType >= 0 && breakType < 32 && (((uint32_t)1 << breakType) & fTypes)) {
    // TODO: Why does icu4c have this?
    result = divideUpDictionaryRange(text, rangeStart, rangeEnd, foundBreaks);
    text.setIndex(current);

    return result;
}
 

/**
 * Sets the current iteration position to the end of the text.
 * (i.e., the CharacterIterator's ending offset).
 * @return The text's past-the-end offset.
 */
@Override
public int last() {
    CharacterIterator t = getText();

    // I'm not sure why, but t.last() returns the offset of the last character,
    // rather than the past-the-end offset
    t.setIndex(t.getEndIndex());
    return t.getIndex();
}
 

public boolean backUp(CharacterIterator fIter) {
    if (current > 0) {
        fIter.setIndex(offset + lengths[--current]);
        return true;
    }
    return false;
}
 

/**
 * Sets the current iteration position to the first boundary position after
 * the specified position.
 * @param offset The position to begin searching forward from
 * @return The position of the first boundary after "offset"
 */
public int following(int offset) {
    CharacterIterator text = getText();
    checkOffset(offset, text);

    // if we have no cached break positions, or if "offset" is outside the
    // range covered by the cache, then dump the cache and call our
    // inherited following() method.  This will call other methods in this
    // class that may refresh the cache.
    if (cachedBreakPositions == null || offset < cachedBreakPositions[0] ||
            offset >= cachedBreakPositions[cachedBreakPositions.length - 1]) {
        cachedBreakPositions = null;
        return super.following(offset);
    }

    // on the other hand, if "offset" is within the range covered by the
    // cache, then just search the cache for the first break position
    // after "offset"
    else {
        positionInCache = 0;
        while (positionInCache < cachedBreakPositions.length
               && offset >= cachedBreakPositions[positionInCache]) {
            ++positionInCache;
        }
        text.setIndex(cachedBreakPositions[positionInCache]);
        return text.getIndex();
    }
}
 

/**
 * Sets the current iteration position to the first boundary position after
 * the specified position.
 * @param offset The position to begin searching forward from
 * @return The position of the first boundary after "offset"
 */
@Override
public int following(int offset) {
    CharacterIterator text = getText();
    checkOffset(offset, text);

    // if we have no cached break positions, or if "offset" is outside the
    // range covered by the cache, then dump the cache and call our
    // inherited following() method.  This will call other methods in this
    // class that may refresh the cache.
    if (cachedBreakPositions == null || offset < cachedBreakPositions[0] ||
            offset >= cachedBreakPositions[cachedBreakPositions.length - 1]) {
        cachedBreakPositions = null;
        return super.following(offset);
    }

    // on the other hand, if "offset" is within the range covered by the
    // cache, then just search the cache for the first break position
    // after "offset"
    else {
        positionInCache = 0;
        while (positionInCache < cachedBreakPositions.length
               && offset >= cachedBreakPositions[positionInCache]) {
            ++positionInCache;
        }
        text.setIndex(cachedBreakPositions[positionInCache]);
        return text.getIndex();
    }
}
 

/**
 * Sets the current iteration position to the end of the text.
 * (i.e., the CharacterIterator's ending offset).
 * @return The text's past-the-end offset.
 */
@Override
public int last() {
    CharacterIterator t = getText();

    // I'm not sure why, but t.last() returns the offset of the last character,
    // rather than the past-the-end offset
    t.setIndex(t.getEndIndex());
    return t.getIndex();
}
 

/**
 * Sets the iterator to refer to the last boundary position before the
 * specified position.
 * @offset The position to begin searching for a break from.
 * @return The position of the last boundary before the starting position.
 */
@Override
public int preceding(int offset) {
    // if we start by updating the current iteration position to the
    // position specified by the caller, we can just use previous()
    // to carry out this operation
    CharacterIterator text = getText();
    checkOffset(offset, text);
    text.setIndex(offset);
    return previous();
}
 

/**
 * Sets the current iteration position to the first boundary position after
 * the specified position.
 * @param offset The position to begin searching forward from
 * @return The position of the first boundary after "offset"
 */
@Override
public int following(int offset) {
    CharacterIterator text = getText();
    checkOffset(offset, text);

    // if we have no cached break positions, or if "offset" is outside the
    // range covered by the cache, then dump the cache and call our
    // inherited following() method.  This will call other methods in this
    // class that may refresh the cache.
    if (cachedBreakPositions == null || offset < cachedBreakPositions[0] ||
            offset >= cachedBreakPositions[cachedBreakPositions.length - 1]) {
        cachedBreakPositions = null;
        return super.following(offset);
    }

    // on the other hand, if "offset" is within the range covered by the
    // cache, then just search the cache for the first break position
    // after "offset"
    else {
        positionInCache = 0;
        while (positionInCache < cachedBreakPositions.length
               && offset >= cachedBreakPositions[positionInCache]) {
            ++positionInCache;
        }
        text.setIndex(cachedBreakPositions[positionInCache]);
        return text.getIndex();
    }
}
 

static final String substring(CharacterIterator iterator, int begin, int end) {
    char[] src = new char[end-begin];
    for (int i = 0;  i < src.length;  i ++)
        src[i] = iterator.setIndex(i+begin);
    return new String(src);
}
 

@Override
public Object clone() {
    CharacterIterator ret = new CharSequenceCharacterIterator(charSequence);
    ret.setIndex(index);
    return ret;
}
 

/**
 * Moves the iterator backwards, to the last boundary preceding this one.
 * @return The position of the last boundary position preceding this one.
 * @stable ICU 2.0
 */
@Override
public int previous() {
    int result;
    int startPos;

    CharacterIterator text = getText();

    fLastStatusIndexValid = false;

    // if we have cached break positions and we're still in the range
    // covered by them, just move one step backward in the cache
    if (fCachedBreakPositions != null) {
        if (fPositionInCache > 0) {
            --fPositionInCache;
            // If we're at the beginning of the cache, need to reevaluate the
            // rule status
            if (fPositionInCache <= 0) {
                fLastStatusIndexValid = false;
            }
            int pos = fCachedBreakPositions[fPositionInCache];
            text.setIndex(pos);
            return pos;
        } else {
            reset();
        }
    }

    // if we're already sitting at the beginning of the text, return DONE
    startPos = current();
    if (fText == null || startPos == fText.getBeginIndex()) {
        fLastRuleStatusIndex  = 0;
        fLastStatusIndexValid = true;
        return BreakIterator.DONE;
    }

    // Rules with an exact reverse table are handled here.
    if (fRData.fSRTable != null || fRData.fSFTable != null) {
        result =  handlePrevious(fRData.fRTable);
        if (fDictionaryCharCount > 0) {
            result = checkDictionary(result, startPos, true);
        }
        return result;
    }

    // old rule syntax
    // set things up.  handlePrevious() will back us up to some valid
    // break position before the current position (we back our internal
    // iterator up one step to prevent handlePrevious() from returning
    // the current position), but not necessarily the last one before
    // where we started

    int       start = current();

    previous32(fText);
    int       lastResult    = handlePrevious(fRData.fRTable);
    if (lastResult == BreakIterator.DONE) {
        lastResult = fText.getBeginIndex();
        fText.setIndex(lastResult);
    }
    result = lastResult;
    int      lastTag       = 0;
    boolean  breakTagValid = false;

    // iterate forward from the known break position until we pass our
    // starting point.  The last break position before the starting
    // point is our return value

    for (;;) {
        result         = next();
        if (result == BreakIterator.DONE || result >= start) {
            break;
        }
        lastResult     = result;
        lastTag        = fLastRuleStatusIndex;
        breakTagValid  = true;
    }

    // fLastBreakTag wants to have the value for section of text preceding
    // the result position that we are to return (in lastResult.)  If
    // the backwards rules overshot and the above loop had to do two or more
    // handleNext()s to move up to the desired return position, we will have a valid
    // tag value. But, if handlePrevious() took us to exactly the correct result position,
    // we wont have a tag value for that position, which is only set by handleNext().

    // Set the current iteration position to be the last break position
    // before where we started, and then return that value.
    fText.setIndex(lastResult);
    fLastRuleStatusIndex  = lastTag;       // for use by getRuleStatus()
    fLastStatusIndexValid = breakTagValid;
    return lastResult;
}
 

/**
 * This method is the actual implementation of the next() method.  All iteration
 * vectors through here.  This method initializes the state machine to state 1
 * and advances through the text character by character until we reach the end
 * of the text or the state machine transitions to state 0.  We update our return
 * value every time the state machine passes through a possible end state.
 */
protected int handleNext() {
    // if we're already at the end of the text, return DONE.
    CharacterIterator text = getText();
    if (text.getIndex() == text.getEndIndex()) {
        return BreakIterator.DONE;
    }

    // no matter what, we always advance at least one character forward
    int result = getNextIndex();
    int lookaheadResult = 0;

    // begin in state 1
    int state = START_STATE;
    int category;
    int c = getCurrent();

    // loop until we reach the end of the text or transition to state 0
    while (c != CharacterIterator.DONE && state != STOP_STATE) {

        // look up the current character's character category (which tells us
        // which column in the state table to look at)
        category = lookupCategory(c);

        // if the character isn't an ignore character, look up a state
        // transition in the state table
        if (category != IGNORE) {
            state = lookupState(state, category);
        }

        // if the state we've just transitioned to is a lookahead state,
        // (but not also an end state), save its position.  If it's
        // both a lookahead state and an end state, update the break position
        // to the last saved lookup-state position
        if (lookaheadStates[state]) {
            if (endStates[state]) {
                result = lookaheadResult;
            }
            else {
                lookaheadResult = getNextIndex();
            }
        }

        // otherwise, if the state we've just transitioned to is an accepting
        // state, update the break position to be the current iteration position
        else {
            if (endStates[state]) {
                result = getNextIndex();
            }
        }

        c = getNext();
    }

    // if we've run off the end of the text, and the very last character took us into
    // a lookahead state, advance the break position to the lookahead position
    // (the theory here is that if there are no characters at all after the lookahead
    // position, that always matches the lookahead criteria)
    if (c == CharacterIterator.DONE && lookaheadResult == text.getEndIndex()) {
        result = lookaheadResult;
    }

    text.setIndex(result);
    return result;
}
 

static final String substring(CharacterIterator iterator, int begin, int end) {
    char[] src = new char[end-begin];
    for (int i = 0;  i < src.length;  i ++)
        src[i] = iterator.setIndex(i+begin);
    return new String(src);
}
 

/**
 * This method is the actual implementation of the next() method.  All iteration
 * vectors through here.  This method initializes the state machine to state 1
 * and advances through the text character by character until we reach the end
 * of the text or the state machine transitions to state 0.  We update our return
 * value every time the state machine passes through a possible end state.
 */
protected int handleNext() {
    // if we're already at the end of the text, return DONE.
    CharacterIterator text = getText();
    if (text.getIndex() == text.getEndIndex()) {
        return BreakIterator.DONE;
    }

    // no matter what, we always advance at least one character forward
    int result = getNextIndex();
    int lookaheadResult = 0;

    // begin in state 1
    int state = START_STATE;
    int category;
    int c = getCurrent();

    // loop until we reach the end of the text or transition to state 0
    while (c != CharacterIterator.DONE && state != STOP_STATE) {

        // look up the current character's character category (which tells us
        // which column in the state table to look at)
        category = lookupCategory(c);

        // if the character isn't an ignore character, look up a state
        // transition in the state table
        if (category != IGNORE) {
            state = lookupState(state, category);
        }

        // if the state we've just transitioned to is a lookahead state,
        // (but not also an end state), save its position.  If it's
        // both a lookahead state and an end state, update the break position
        // to the last saved lookup-state position
        if (lookaheadStates[state]) {
            if (endStates[state]) {
                result = lookaheadResult;
            }
            else {
                lookaheadResult = getNextIndex();
            }
        }

        // otherwise, if the state we've just transitioned to is an accepting
        // state, update the break position to be the current iteration position
        else {
            if (endStates[state]) {
                result = getNextIndex();
            }
        }

        c = getNext();
    }

    // if we've run off the end of the text, and the very last character took us into
    // a lookahead state, advance the break position to the lookahead position
    // (the theory here is that if there are no characters at all after the lookahead
    // position, that always matches the lookahead criteria)
    if (c == CharacterIterator.DONE && lookaheadResult == text.getEndIndex()) {
        result = lookaheadResult;
    }

    text.setIndex(result);
    return result;
}
 

/**
 * Returns the logical bounds of the characters indexed in the
 * specified {@link CharacterIterator} in the
 * specified <code>FontRenderContext</code>.  The logical bounds
 * contains the origin, ascent, advance, and height, which includes
 * the leading.  The logical bounds does not always enclose all the
 * text.  For example, in some languages and in some fonts, accent
 * marks can be positioned above the ascent or below the descent.
 * To obtain a visual bounding box, which encloses all the text,
 * use the {@link TextLayout#getBounds() getBounds} method of
 * <code>TextLayout</code>.
 * <p>Note: The returned bounds is in baseline-relative coordinates
 * (see {@link java.awt.Font class notes}).
 * @param ci the specified <code>CharacterIterator</code>
 * @param beginIndex the initial offset in <code>ci</code>
 * @param limit the end offset in <code>ci</code>
 * @param frc the specified <code>FontRenderContext</code>
 * @return a <code>Rectangle2D</code> that is the bounding box of the
 * characters indexed in the specified <code>CharacterIterator</code>
 * in the specified <code>FontRenderContext</code>.
 * @see FontRenderContext
 * @see Font#createGlyphVector
 * @since 1.2
 * @throws IndexOutOfBoundsException if <code>beginIndex</code> is
 *         less than the start index of <code>ci</code>, or
 *         <code>limit</code> is greater than the end index of
 *         <code>ci</code>, or <code>beginIndex</code> is greater
 *         than <code>limit</code>
 */
public Rectangle2D getStringBounds(CharacterIterator ci,
                                int beginIndex, int limit,
                                   FontRenderContext frc) {
    int start = ci.getBeginIndex();
    int end = ci.getEndIndex();

    if (beginIndex < start) {
        throw new IndexOutOfBoundsException("beginIndex: " + beginIndex);
    }
    if (limit > end) {
        throw new IndexOutOfBoundsException("limit: " + limit);
    }
    if (beginIndex > limit) {
        throw new IndexOutOfBoundsException("range length: " +
                                            (limit - beginIndex));
    }

    char[]  arr = new char[limit - beginIndex];

    ci.setIndex(beginIndex);
    for(int idx = 0; idx < arr.length; idx++) {
        arr[idx] = ci.current();
        ci.next();
    }

    return getStringBounds(arr,0,arr.length,frc);
}
 

/**
 * Returns the logical bounds of the characters indexed in the
 * specified {@link CharacterIterator} in the
 * specified <code>FontRenderContext</code>.  The logical bounds
 * contains the origin, ascent, advance, and height, which includes
 * the leading.  The logical bounds does not always enclose all the
 * text.  For example, in some languages and in some fonts, accent
 * marks can be positioned above the ascent or below the descent.
 * To obtain a visual bounding box, which encloses all the text,
 * use the {@link TextLayout#getBounds() getBounds} method of
 * <code>TextLayout</code>.
 * <p>Note: The returned bounds is in baseline-relative coordinates
 * (see {@link java.awt.Font class notes}).
 * @param ci the specified <code>CharacterIterator</code>
 * @param beginIndex the initial offset in <code>ci</code>
 * @param limit the end offset in <code>ci</code>
 * @param frc the specified <code>FontRenderContext</code>
 * @return a <code>Rectangle2D</code> that is the bounding box of the
 * characters indexed in the specified <code>CharacterIterator</code>
 * in the specified <code>FontRenderContext</code>.
 * @see FontRenderContext
 * @see Font#createGlyphVector
 * @since 1.2
 * @throws IndexOutOfBoundsException if <code>beginIndex</code> is
 *         less than the start index of <code>ci</code>, or
 *         <code>limit</code> is greater than the end index of
 *         <code>ci</code>, or <code>beginIndex</code> is greater
 *         than <code>limit</code>
 */
public Rectangle2D getStringBounds(CharacterIterator ci,
                                int beginIndex, int limit,
                                   FontRenderContext frc) {
    int start = ci.getBeginIndex();
    int end = ci.getEndIndex();

    if (beginIndex < start) {
        throw new IndexOutOfBoundsException("beginIndex: " + beginIndex);
    }
    if (limit > end) {
        throw new IndexOutOfBoundsException("limit: " + limit);
    }
    if (beginIndex > limit) {
        throw new IndexOutOfBoundsException("range length: " +
                                            (limit - beginIndex));
    }

    char[]  arr = new char[limit - beginIndex];

    ci.setIndex(beginIndex);
    for(int idx = 0; idx < arr.length; idx++) {
        arr[idx] = ci.current();
        ci.next();
    }

    return getStringBounds(arr,0,arr.length,frc);
}