TimedTextObject -> getCaptionByTime

[ldimitroff]

We're using your code to parse captions and display it. Here's a code improvement that did in order to get captions by time

    private static final Integer INVALID_INDEX = -1;
    private Caption currentCaption = null;
    private Caption nextCaption = null;
    private Caption firstCaption = null;
    private Caption lastCaption = null;
    private Iterator<Integer> indexIterator = null;

    public void initCaptionsSearch() {
        currentCaption = null;
        nextCaption = getCaptionAtIndex(getFirstIndex());
        firstCaption = nextCaption;
        lastCaption = getCaptionAtIndex(getLastIndex());
        indexIterator = null;
        if (captions != null)
            indexIterator = captions.navigableKeySet().iterator();
    }

    private Integer getFirstIndex() {
        if (captions != null && !captions.isEmpty())
            return captions.firstKey();

        return INVALID_INDEX;
    }

    private Integer getLastIndex() {
        if (captions != null && !captions.isEmpty())
            return captions.lastKey();

        return INVALID_INDEX;
    }

    private void advanceToNext() {
        currentCaption = nextCaption;
        Integer nextIndex;
        if (indexIterator != null && indexIterator.hasNext())
            nextIndex = indexIterator.next();
        else
            nextIndex = INVALID_INDEX;
        nextCaption = getCaptionAtIndex(nextIndex);
    }

    private void advanceToLast() {
        currentCaption = getCaptionAtIndex(getLastIndex());
        nextCaption = null;
        indexIterator = null;
    }

    private Caption getCaptionAtIndex(Integer index) {
        if (captions != null && index != INVALID_INDEX)
            return captions.get(index);
        return null;
    }

    public Caption getCaption(int currentMillis) {

        if (firstCaption == null || lastCaption == null)
            return null;

        if (currentCaption == null && nextCaption == null)
            return null;

        if (firstCaption.start.mseconds > currentMillis) {
            if (currentCaption != null)
                initCaptionsSearch();
            return null;
        }

        if (lastCaption.end.mseconds < currentMillis) {
            advanceToLast();
            return null;
        }

        Caption testCaption = currentCaption;
        boolean usingNext = false;
        if (testCaption == null) {
            usingNext = true;
            testCaption = nextCaption;
        }

        int comparation = testCaption.compareToMillis(currentMillis);
        switch (comparation) {
        case Caption.COMPARATION_CAPTION_ENCLOSES:
            if (usingNext)
                advanceToNext();
            return testCaption;
        case Caption.COMPARATION_CAPTION_IS_BEFORE:
            return lookForwardToEnd(currentMillis);
        case Caption.COMPARATION_CAPTION_IS_AFTER:
            if (usingNext) {
                return null;
            } else {
                initCaptionsSearch();
                return lookForwardUntilCaption(currentMillis, testCaption);
            }
        }
        return null;
    }

    private Caption lookForwardToEnd(int millis) {
        return lookForwardUntilCaption(millis,
                getCaptionAtIndex(getLastIndex()));
    }

    private Caption lookForwardUntilCaption(int millis, Caption toCaption) {
        if (toCaption == null)
            return null;

        while (nextCaption != null && currentCaption != toCaption) {
            int comparation = nextCaption.compareToMillis(millis);
            switch (comparation) {
            case Caption.COMPARATION_CAPTION_ENCLOSES:
                advanceToNext();
                return currentCaption;
            case Caption.COMPARATION_CAPTION_IS_BEFORE:
                break;
            case Caption.COMPARATION_CAPTION_IS_AFTER:
                return null;
            }
            advanceToNext();
        }
        return null;
    }

And for Caption class:

    public static final int COMPARATION_CAPTION_IS_BEFORE = -1;
    public static final int COMPARATION_CAPTION_IS_AFTER = 1;
    public static final int COMPARATION_CAPTION_ENCLOSES = 0;

    public int compareToMillis(int millis) {
        // Starts before current time
        if (start.mseconds <= millis) {
            // Starts before and ends after millis
            if (end.mseconds >= millis) {
                // millis is between start and end
                return COMPARATION_CAPTION_ENCLOSES;
            } else { // Starts and ends before millis
                return COMPARATION_CAPTION_IS_BEFORE;
            }
        } else { // Starts after millis
            return COMPARATION_CAPTION_IS_AFTER;
        }
    }

[JDaren]

Nice! I'm glad my code is helpful, when I decided to open-source it all I was hoping was for my efforts to not go wasted in just getting me a good university grade. However, the way I stored the captions in a TreeMap means the sorting is inherent, and the search, acceptable... Your code seems very implementation specific, I'm having trouble deciding if it will be usable to others or a good fit in a TTO... I'm guessing this is a sort of informal pull request? You would like to give something to the community and offer them the navigation by time functionality?

[ldimitroff]

yeah, I mean, if you want to use it, this is what we did adapting on your code and give a navigation as the time goes by, returning the caption related to it's time. It actually can work with anything that uses a tree map. You can always improve this code or just let others implement their own methods, just thought it is a good way to give to the users a navigation by time.

[JDaren]

I'll add it in a helper class, and give you credit in the javadoc. :)