attributedstring.java

java源代码 请看看啊 提点宝贵的意见

            int beginIndex, int endIndex) {
        
        // make sure we have run attribute data vectors
        if (runCount == 0) {
            createRunAttributeDataVectors();
        }
        
        // break up runs if necessary
        int beginRunIndex = ensureRunBreak(beginIndex);
        int endRunIndex = ensureRunBreak(endIndex);
        
        addAttributeRunData(attribute, value, beginRunIndex, endRunIndex);
    }
    
    private final void createRunAttributeDataVectors() {
        // use temporary variables so things remain consistent in case of an exception
        int newRunStarts[] = new int[ARRAY_SIZE_INCREMENT];
        Vector newRunAttributes[] = new Vector[ARRAY_SIZE_INCREMENT];
        Vector newRunAttributeValues[] = new Vector[ARRAY_SIZE_INCREMENT];
        runStarts = newRunStarts;
        runAttributes = newRunAttributes;
        runAttributeValues = newRunAttributeValues;
        runArraySize = ARRAY_SIZE_INCREMENT;
        runCount = 1; // assume initial run starting at index 0
    }

    // ensure there's a run break at offset, return the index of the run
    private final int ensureRunBreak(int offset) {
        return ensureRunBreak(offset, true);
    }

    /**
     * Ensures there is a run break at offset, returning the index of
     * the run. If this results in splitting a run, two things can happen:
     * <ul>
     * <li>If copyAttrs is true, the attributes from the existing run
     *     will be placed in both of the newly created runs.
     * <li>If copyAttrs is false, the attributes from the existing run
     * will NOT be copied to the run to the right (>= offset) of the break,
     * but will exist on the run to the left (< offset).
     * </ul>
     */
    private final int ensureRunBreak(int offset, boolean copyAttrs) {
        if (offset == length()) {
            return runCount;
        }

        // search for the run index where this offset should be
        int runIndex = 0;
        while (runIndex < runCount && runStarts[runIndex] < offset) {
            runIndex++;
        }

        // if the offset is at a run start already, we're done
        if (runIndex < runCount && runStarts[runIndex] == offset) {
            return runIndex;
        }
        
        // we'll have to break up a run
        // first, make sure we have enough space in our arrays
        if (runCount == runArraySize) {
            int newArraySize = runArraySize + ARRAY_SIZE_INCREMENT;
            int newRunStarts[] = new int[newArraySize];
            Vector newRunAttributes[] = new Vector[newArraySize];
            Vector newRunAttributeValues[] = new Vector[newArraySize];
            for (int i = 0; i < runArraySize; i++) {
                newRunStarts[i] = runStarts[i];
                newRunAttributes[i] = runAttributes[i];
                newRunAttributeValues[i] = runAttributeValues[i];
            }
            runStarts = newRunStarts;
            runAttributes = newRunAttributes;
            runAttributeValues = newRunAttributeValues;
            runArraySize = newArraySize;
        }
        
        // make copies of the attribute information of the old run that the new one used to be part of
        // use temporary variables so things remain consistent in case of an exception
        Vector newRunAttributes = null;
        Vector newRunAttributeValues = null;

        if (copyAttrs) {
            Vector oldRunAttributes = runAttributes[runIndex - 1];
            Vector oldRunAttributeValues = runAttributeValues[runIndex - 1];
            if (oldRunAttributes != null) {
                newRunAttributes = (Vector) oldRunAttributes.clone();
            }
            if (oldRunAttributeValues != null) {
                newRunAttributeValues = (Vector) oldRunAttributeValues.clone();
            }
        }
        
        // now actually break up the run
        runCount++;
        for (int i = runCount - 1; i > runIndex; i--) {
            runStarts[i] = runStarts[i - 1];
            runAttributes[i] = runAttributes[i - 1];
            runAttributeValues[i] = runAttributeValues[i - 1];
        }
        runStarts[runIndex] = offset;
        runAttributes[runIndex] = newRunAttributes;
        runAttributeValues[runIndex] = newRunAttributeValues;

        return runIndex;
    }

    // add the attribute attribute/value to all runs where beginRunIndex <= runIndex < endRunIndex
    private void addAttributeRunData(Attribute attribute, Object value,
            int beginRunIndex, int endRunIndex) {

        for (int i = beginRunIndex; i < endRunIndex; i++) {
            int keyValueIndex = -1; // index of key and value in our vectors; assume we don't have an entry yet
            if (runAttributes[i] == null) {
                Vector newRunAttributes = new Vector();
                Vector newRunAttributeValues = new Vector();
                runAttributes[i] = newRunAttributes;
                runAttributeValues[i] = newRunAttributeValues;
            } else {
                // check whether we have an entry already
                keyValueIndex = runAttributes[i].indexOf(attribute);
            }

            if (keyValueIndex == -1) {
                // create new entry
                int oldSize = runAttributes[i].size();
                runAttributes[i].addElement(attribute);
                try {
                    runAttributeValues[i].addElement(value);
                }
                catch (Exception e) {
                    runAttributes[i].setSize(oldSize);
                    runAttributeValues[i].setSize(oldSize);
                }
            } else {
                // update existing entry
                runAttributeValues[i].set(keyValueIndex, value);
            }
        }
    }

    /**
     * Creates an AttributedCharacterIterator instance that provides access to the entire contents of
     * this string.
     *
     * @return An iterator providing access to the text and its attributes.
     */
    public AttributedCharacterIterator getIterator() {
        return getIterator(null, 0, length());
    }

    /**
     * Creates an AttributedCharacterIterator instance that provides access to
     * selected contents of this string.
     * Information about attributes not listed in attributes that the
     * implementor may have need not be made accessible through the iterator.
     * If the list is null, all available attribute information should be made
     * accessible.
     *
     * @param attributes a list of attributes that the client is interested in
     * @return an iterator providing access to the text and its attributes
     */
    public AttributedCharacterIterator getIterator(Attribute[] attributes) {
        return getIterator(attributes, 0, length());
    }

    /**
     * Creates an AttributedCharacterIterator instance that provides access to
     * selected contents of this string.
     * Information about attributes not listed in attributes that the
     * implementor may have need not be made accessible through the iterator.
     * If the list is null, all available attribute information should be made
     * accessible.
     *
     * @param attributes a list of attributes that the client is interested in
     * @param beginIndex the index of the first character
     * @param endIndex the index of the character following the last character
     * @return an iterator providing access to the text and its attributes
     * @exception IllegalArgumentException if beginIndex is less then 0,
     * endIndex is greater than the length of the string, or beginIndex is
     * greater than endIndex.
     */
    public AttributedCharacterIterator getIterator(Attribute[] attributes, int beginIndex, int endIndex) {
        return new AttributedStringIterator(attributes, beginIndex, endIndex);
    }

    // all (with the exception of length) reading operations are private,
    // since AttributedString instances are accessed through iterators.

    // length is package private so that CharacterIteratorFieldDelegate can
    // access it without creating an AttributedCharacterIterator.
    int length() {
        return text.length();
    }
    
    private char charAt(int index) {
        return text.charAt(index);
    }
    
    private synchronized Object getAttribute(Attribute attribute, int runIndex) {
        Vector currentRunAttributes = runAttributes[runIndex];
        Vector currentRunAttributeValues = runAttributeValues[runIndex];
        if (currentRunAttributes == null) {
            return null;
        }
        int attributeIndex = currentRunAttributes.indexOf(attribute);
        if (attributeIndex != -1) {
            return currentRunAttributeValues.elementAt(attributeIndex);
        }
        else {
            return null;
        }
    }

    // gets an attribute value, but returns an annotation only if it's range does not extend outside the range beginIndex..endIndex
    private Object getAttributeCheckRange(Attribute attribute, int runIndex, int beginIndex, int endIndex) {
        Object value = getAttribute(attribute, runIndex);
        if (value instanceof Annotation) {
            // need to check whether the annotation's range extends outside the iterator's range
            if (beginIndex > 0) {
                int currIndex = runIndex;
                int runStart = runStarts[currIndex];
                while (runStart >= beginIndex &&
                        valuesMatch(value, getAttribute(attribute, currIndex - 1))) {
                    currIndex--;
                    runStart = runStarts[currIndex];
                }
                if (runStart < beginIndex) {
                    // annotation's range starts before iterator's range
                    return null;
                }
            }
            int textLength = length();
            if (endIndex < textLength) {
                int currIndex = runIndex;
                int runLimit = (currIndex < runCount - 1) ? runStarts[currIndex + 1] : textLength;
                while (runLimit <= endIndex &&
                        valuesMatch(value, getAttribute(attribute, currIndex + 1))) {
                    currIndex++;
                    runLimit = (currIndex < runCount - 1) ? runStarts[currIndex + 1] : textLength;
                }
                if (runLimit > endIndex) {
                    // annotation's range ends after iterator's range
                    return null;
                }
            }
            // annotation's range is subrange of iterator's range,
            // so we can return the value
        }
        return value;
    }

    // returns whether all specified attributes have equal values in the runs with the given indices
    private boolean attributeValuesMatch(Set attributes, int runIndex1, int runIndex2) {
        Iterator iterator = attributes.iterator();
        while (iterator.hasNext()) {
            Attribute key = (Attribute) iterator.next();
           if (!valuesMatch(getAttribute(key, runIndex1), getAttribute(key, runIndex2))) {
                return false;
            }
        }
        return true;
    }

    // returns whether the two objects are either both null or equal
    private final static boolean valuesMatch(Object value1, Object value2) {
        if (value1 == null) {
            return value2 == null;
        } else {
            return value1.equals(value2);
        }
    }

    /**
     * Appends the contents of the CharacterIterator iterator into the
     * StringBuffer buf.
     */
    private final void appendContents(StringBuffer buf,
                                      CharacterIterator iterator) {
        int index = iterator.getBeginIndex();
        int end = iterator.getEndIndex();

        while (index < end) {
            iterator.setIndex(index++);
            buf.append(iterator.current());
        }
    }

    /**
     * Sets the attributes for the range from offset to the the next run break 
     * (typically the end of the text) to the ones specified in attrs.
     * This is only meant to be called from the constructor!
     */
    private void setAttributes(Map attrs, int offset) {
        if (runCount == 0) {
            createRunAttributeDataVectors();
        }

        int index = ensureRunBreak(offset, false);
        int size;

        if (attrs != null && (size = attrs.size()) > 0) {
            Vector runAttrs = new Vector(size);
            Vector runValues = new Vector(size);
            Iterator iterator = attrs.entrySet().iterator();

            while (iterator.hasNext()) {
                Map.Entry entry = (Map.Entry)iterator.next();

                runAttrs.add(entry.getKey());
                runValues.add(entry.getValue());
            }
            runAttributes[index] = runAttrs;
            runAttributeValues[index] = runValues;	    
        }
    }

    /**
     * Returns true if the attributes specified in last and attrs differ.
     */
    private static boolean mapsDiffer(Map last, Map attrs) {
        if (last == null) {
            return (attrs != null && attrs.size() > 0);
        }
        return (!last.equals(attrs));
    }


    // the iterator class associated with this string class

    final private class AttributedStringIterator implements AttributedCharacterIterator {
        
        // note on synchronization:
        // we don't synchronize on the iterator, assuming that an iterator is only used in one thread.
        // we do synchronize access to the AttributedString however, since it's more likely to be shared between threads.

        // start and end index for our iteration
        private int beginIndex;
        private int endIndex;
        
        // attributes that our client is interested in
        private Attribute[] relevantAttributes;

        // the current index for our iteration
        // invariant: beginIndex <= currentIndex <= endIndex
        private int currentIndex;

        // information about the run that includes currentIndex
        private int currentRunIndex;
        private int currentRunStart;
        private int currentRunLimit;
        
        // constructor
        AttributedStringIterator(Attribute[] attributes, int beginIndex, int endIndex) {
        
            if (beginIndex < 0 || beginIndex > endIndex || endIndex > length()) {
                throw new IllegalArgumentException("Invalid substring range");
            }
            
            this.beginIndex = beginIndex;
            this.endIndex = endIndex;
            this.currentIndex = beginIndex;