bookcounter.java

一个java源代码包

import org.xml.sax.*;
import org.xml.sax.helpers.ParserFactory;
import java.io.*;
import org.xml.sax.Parser;
import com.sun.xml.parser.*;
import java.util.*;


public class BookCounter extends HandlerBase
{
	private int count=0;
	private double totalPrice=0.0;
	private StringBuffer content=new StringBuffer();
	private Locator locator;
	private Stack context= new Stack();	
	
	public void BookCount() throws Exception
	{
		Parser p=ParserFactory.makeParser("com.sun.xml.parser.Parser");
		p.setDocumentHandler(this);
		p.parse((new File("c:/books.xml")).toURI().toString());  
	}
	
	public void setDocumentLocator(Locator loc)
	{
		locator=loc;
	}
	public void startElement(String name, AttributeList atts) throws SAXException
	{
		ElementDetails  details= new ElementDetails(name,atts);
		context.push(details);
		//System.out.println("StartElement: ElmentName:"+name);
		if(name.equals("book"))
		{
			 if(isFiction()) 
			 {
			 	count++;
			 	System.out.println("count="+count);			 				 	
			 }
		}
		
	}
	
	public void characters(char[] chars,int start, int len) throws SAXException
	{
		content.append(chars,start,len);
	}
	
	public void endElement(String name)throws SAXException
	{
		if(name.equals("price") && isFiction() && !isVolume())
		{
			try
			{
				double price=new Double(content.toString()).doubleValue();
				totalPrice+=price;
				System.out.println("TotalPrice="+totalPrice);
			}
			catch(java.lang.NumberFormatException err)
			{
				if(locator!=null)
				{
					System.err.println("Error in "+locator.getSystemId()+
										"at lint "+locator.getLineNumber()+
										"at colume "+locator.getColumnNumber());
										
				}
				throw new SAXException("Price is not numberic",err);
			}
		}
		content.setLength(0);
		context.pop();
	}
	
	public void endDocument() throws SAXException
	{
		System.out.println("The average price of fiction books is "+totalPrice/count);
		System.out.println("There are "+count+" books");
	}
	
	
	
	public static void main(String args[]) throws Exception
	{
		(new BookCounter()).BookCount();
	}
	
	private boolean isFiction()
	{
		boolean test = false;
		for(int  p=context.size()-1;p>=0;p--)
		{
			ElementDetails elem = (ElementDetails)context.elementAt(p);
			if(elem.name.equals("book")&&elem.attributes.getValue("category")!=null && 
				elem.attributes.getValue("category").equals("fiction"))
			{
				System.out.println("-----------------------------------");
				return true;
			}
		}
		return false;
	}
	
	private boolean isVolume()
	{
			boolean test = false;
		for(int  p=context.size()-1;p>=0;p--)
		{
			ElementDetails elem = (ElementDetails)context.elementAt(p);
			if(elem.name.equals("volume"))				
			{
				return true;
			}
		}
		return false;
	}	
	private class ElementDetails
	{
		public String name;
		public AttributeList attributes;
		public ElementDetails(String name,AttributeList atts)
		{
			this.name=name;
			this.attributes = new org.xml.sax.helpers.AttributeListImpl(atts);
		}
	}
}