searchforsizelist.java

Java程序设计(美) David D. Riley著 机械工业出版社 书籍配套 代码

import javax.swing.JButton;
import java.awt.Component;
public class SearchForSizeList 
							extends SimpleList<JButton> {
	/**	post:	size() == 0 
	 *          and iterator == 0	
	 */
	public SearchForSizeList()  {
		super();
	}  

	/**	post:	result == (this contains an item with identical 
	 *						getWidth() and getHeight() values as c)
	 *          and  iterator == 0 
	 */
	public boolean containsSameSize(JButton b)   {
		boolean  found;
		Component temp;
		reset();
		found = false;
		while ( !found  &&  hasNext() )  {
			temp = next();
			found = (temp.getWidth()==b.getWidth() 
						&& temp.getHeight()==b.getHeight());
		}
		reset();
		return found;
	} 
    	
    /**	note:	This method is shown in Figure 11.16
	 *	post:	containsSameSize(b) implies
	 *				(result has the same dimensions as b
	 *				 and the iterator is positioned after result)
	 *			and (not containsSameSizeList(b))  implies
 	 *				result == null 
	 */
	public JButton nextWithSameSize(JButton b)   {
		boolean  found;
		JButton tempButton = null;
		found = false;
		while ( !found  &&  hasNext() )  {
			tempButton = next();
			found = (tempButton.getWidth()==b.getWidth() 
						&& tempButton.getHeight()==b.getHeight());
		}
		if (found)  
			return tempButton;
		else
			return null;
	} 

}