private double calculateDistanceOfTwoBox(BoundingBox box1, BoundingBox to) {
    if (box1.getPage() != to.getPage()) {
        return 1000 * Math.abs(box1.getPage() - to.getPage());
    }

    //the current box is completely "lefter"
    boolean left = box1.getX2() < to.getX();
    boolean right = to.getX2() < box1.getX();
    boolean bottom = to.getY2() < box1.getY();
    boolean top = box1.getY2() < to.getY();
    if (top && left) {
        return dist(box1.getX2(), box1.getY2(), to.getX(), to.getY());
    } else if (left && bottom) {
        return dist(box1.getX2(), box1.getY(), to.getX(), to.getY2());
    } else if (bottom && right) {
        return dist(box1.getX(), box1.getY(), to.getX2(), to.getY2());
    } else if (right && top) {
        return dist(box1.getX(), box1.getY2(), to.getX2(), to.getY());
    } else if (left) {
        return to.getX() - box1.getX2();
    } else if (right) {
        return box1.getX() - to.getX2();
    } else if (bottom) {
        return box1.getY() - to.getY2();
    } else if (top) {
        return to.getY() - box1.getY2();
    } else {
        return 0;
    }

}
 

public List<TaggingTokenCluster> cluster() {
        
        List<TaggingTokenCluster> result = new ArrayList<>();

        PeekingIterator<LabeledTokensContainer> it = Iterators.peekingIterator(taggingTokenSynchronizer);
        if (!it.hasNext() || (it.peek() == null)) {
            return Collections.emptyList();
        }

        // a boolean is introduced to indicate the start of the sequence in the case the label
        // has no beginning indicator (e.g. I-)
        boolean begin = true;
        TaggingTokenCluster curCluster = new TaggingTokenCluster(it.peek().getTaggingLabel());
        BoundingBox curBox=null;
 
        
        
        while (it.hasNext()) {
            LabeledTokensContainer cont = it.next();
            BoundingBox b = BoundingBox.fromLayoutToken(cont.getLayoutTokens().get(0));
            if(!curCluster.concatTokens().isEmpty()){
                curBox = BoundingBox.fromLayoutToken(curCluster.concatTokens().get(0));
                if(b.distanceTo(curBox)>600){
                    curCluster = new TaggingTokenCluster(cont.getTaggingLabel());
                    result.add(curCluster);
                }
            }
            
            if (begin || cont.isBeginning() || cont.getTaggingLabel() != curCluster.getTaggingLabel()) {
                curCluster = new TaggingTokenCluster(cont.getTaggingLabel());
                result.add(curCluster);
            }
            
            //for table, seperate caption and content
            if(curCluster!=null){
                String tableStr = LayoutTokensUtil.normalizeText(curCluster.concatTokens());
                if(tableStr.matches(".*?(Table|TABLE) \\d+(:|\\.| [A-Z]).*?")){
//                if(tableStr.matches(".*?(Table|TABLE|Figure|FIGURE) \\d+(:|\\.).*?")){
                    if(toText(curCluster.getLastContainer().getLayoutTokens()).equalsIgnoreCase(". \n\n")){ 
                        curCluster = new TaggingTokenCluster(cont.getTaggingLabel());
                        result.add(curCluster);
                    }
                }
            }
                    
                    
            curCluster.addLabeledTokensContainer(cont);
            if (begin)
                begin = false;
        }

        return result;
    }
 

public void setBoundingBoxes(List<BoundingBox> boundingBoxes) {
	this.boundingBoxes = boundingBoxes;
}
 

public List<BoundingBox> getBoundingBoxes() {
	return boundingBoxes;
}
 

public void addBoundingBoxes(BoundingBox boundingBox) {
	if (this.boundingBoxes == null)
		this.boundingBoxes = new ArrayList<BoundingBox>();
	this.boundingBoxes.add(boundingBox);
}
 

public void setBoundingBoxes(List<BoundingBox> boundingBoxes) {
    this.boundingBoxes = boundingBoxes;
}
 

public List<BoundingBox> getBoundingBoxes() {
    return boundingBoxes;
}
 

public void addBoundingBoxes(BoundingBox boundingBox) {
    if (this.boundingBoxes == null)
        this.boundingBoxes = new ArrayList<BoundingBox>();
    this.boundingBoxes.add(boundingBox);
}
 

public void setBoundingBoxes(List<BoundingBox> boundingBoxes) {
	this.boundingBoxes = boundingBoxes;
}
 

public List<BoundingBox> getBoundingBoxes() {
	return boundingBoxes;
}
 

public void addBoundingBoxes(BoundingBox boundingBox) {
	if (this.boundingBoxes == null)
		this.boundingBoxes = new ArrayList<BoundingBox>();
	this.boundingBoxes.add(boundingBox);
}