dvdlibrary.java

用Struts实现的一个例子

package dvd.model;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Collections;
import java.util.LinkedList;
import java.util.List;

public class DVDLibrary {

	private static final List DVDITEM_CACHE = new LinkedList();
	
	public DVDLibrary()
	{
		synchronized (DVDITEM_CACHE)
		{
			if (DVDITEM_CACHE.isEmpty())
			{
				caheDVDItem();
			}
		}
	}
	
	@SuppressWarnings("unchecked")
	public DVDItem createDVDItem(String title,String year,String genre)
	{
		int nextID = DVDITEM_CACHE.size() + 1;
		
		DVDItem item = new DVDItem(nextID,title,year,genre);
		
		storeDVDItem(item);
		
		DVDITEM_CACHE.add(item);
		return item;
	}
	
	@SuppressWarnings("unchecked")
	private static void caheDVDItem()
	{
		//String dataDirectory = System.getProperty("dvd.model.dataDirectory");
		String DVDFile = "C:\\my-library.txt";
		
		BufferedReader DVDReader = null;
		
		try
		{
			DVDReader = new BufferedReader(new FileReader(DVDFile));
			String record;
			
			while( (record = DVDReader.readLine())!= null)
			{
				String[] elemets = record.split("\\|");
				
				int count = 0;
				while(true)
				{
					if(count < elemets.length)
					{
						int objectID = Integer.parseInt(elemets[count++]);
						String title = elemets[count++];
						String year = elemets[count++];
						String genre = elemets[count++];
						DVDItem item = new DVDItem(objectID,title,year,genre);
						DVDITEM_CACHE.add(item);
					}
					else
						break;
				}

			}

		}catch(Exception e)
		{
			System.err.println(e);
		}finally
		{
			if (DVDReader!= null)
			{
				try
				{
					DVDReader.close();
				}catch(IOException e){}
			}
		}// end of finally
		
	}
	
	@SuppressWarnings("unused")
	private void storeDVDItem(DVDItem item)
	{
		//String dataDirectory = System.getProperty("dvd.model.dataDirectory");
		String DVDFile = "C:\\my-library.txt";
		PrintWriter DVDWriter = null;
		
		try
		{
			DVDWriter  = new PrintWriter(new FileWriter(DVDFile,true));
			
			DVDWriter.print("|");
			DVDWriter.print(item.getObjectID());
			DVDWriter.print("|");
			DVDWriter.print(item.getTitle());
			DVDWriter.print("|");
			DVDWriter.print(item.getYear());
			DVDWriter.print("|");
			DVDWriter.print(item.getGenre());
			
		}catch(Exception e)
		{
			System.err.println(e);
		}finally
		{
			if (DVDWriter!= null)
			{
				try
				{
					DVDWriter.close();
				}catch(Exception e){ System.err.println(e);}
			}
		}
	}
	
	@SuppressWarnings("unchecked")
	public List getAllLDVDItem()
	{
		return Collections.unmodifiableList(DVDITEM_CACHE);
	}
	
	public static void main(String args[])
	{
		new DVDLibrary();
	}
}