pagecounter.java

textviewer 一个手机上的文本浏览器实现

package textViewer;

// TODO: implement as RangedInteger

public class PageCounter {

    private int page;
    private PageChangable callback;
    private int min;
    private int max;

    public PageCounter(PageChangable callback, int page, int min, int max) 
    {
    	this.callback = callback;
	this.page = page;
	this.min = min;
	this.max = max;
    }


    public PageCounter(PageChangable callback) 
    {
	this(callback, 1,1,1);
     }

    public int getMax()
    {
	return max;
    }

    public void setMax(int max)
    {
	this.max = max;
    }

    public int getValue() 
    {
	return page;
    }

    public void setValueWithErrors(int newPage) throws IndexOutOfBoundsException
    {
	if ( (newPage >= min) && (newPage <= max) )
	    {
		page = newPage;
		callback.pageChanged();
	    }
	else {throw new IndexOutOfBoundsException("PageCounter.setValueWithErrors: requested page number " + Integer.toString(newPage) + " is not in between minimum limit " + Integer.toString(min) + " and maximum limit " + Integer.toString(max));}
    }
	
    public void setValue(int newPage)
    {
	try {
	    setValueWithErrors(newPage);
	} catch (IndexOutOfBoundsException e) {}
    }

    public void add(int arg) 
    {
	setValue(getValue() + arg);
    }

    public void addAsFarAsYouCan(int arg) 
    {
	try {
	    setValueWithErrors(getValue() + arg);
	}
	catch (IndexOutOfBoundsException e) 
	    {
		if (arg > 0) {setValue(max);}
		else if (arg < 0) {setValue(min);}
	    }
    }
}