loadrecorder.java

本程序在Unix_Linux环境下用Java语言编写的文件下载程序

package loader.recorder;

import java.util.*;
import java.io.*;
/**
	LoadRecorder records the information of every loader, including the loading resource's properties.
	ResourceURL-->records the actual resource location.
	DestinationFile-->when completed, the resource will be saved in this file.

	ThreadSize-->remember how many threads that the loader manager starts.
	Thread(i)-->records the current loading value, end position and start position.
*/
public class LoadRecorder extends Hashtable<String, List<String>> implements Recorder {
	
	public LoadRecorder(){
		super();
	}
	public LoadRecorder( Map<String, List<String>> h ){                
		super( h );
                System.out.println( "create recorder." );
	}
	/*
		call by loader manager to store information.
		manager set these properties through put methos of Map class.
	*/
        synchronized public List<String> put( String key, List<String> value ){
            return super.put( key, value );
        }
        synchronized public List<String> get( int index ){
            return super.get( index );
        }
	public List<String> getList( String str ){
		List<String> l = new ArrayList<String>();
		StringTokenizer st = new StringTokenizer( str, "," );
		while (st.hasMoreTokens()) {
			 l.add( st.nextToken() );
		 }
		return l;
	}
	public String getString( List<String> l ){
		String str = "";
		int i;
		for( i=0; i<l.size()-1; i++ ){
			str += ( l.get( i ) + ",");
		}
		str += l.get( i );
		return str;
	}
        public List<String> getList( String[] strs ){
		List<String> l = new ArrayList<String>();
		for( int i=0; i<strs.length; i++ ){
			l.add( strs[i] );
		}
		return l;
	}
	/*
		call by loader to record his activities.
	*/
	synchronized public void log( String name, int value ){
		List<String> l = get( name );
                int pre = 0;
                try{
                    pre = Integer.parseInt( l.get( 0 ) );
                }catch( Exception e ){}
                pre += value;
                l.remove( 0 );
                l.add( 0, ""+pre );
	}

	/*
		persist this instance. log all of the information.
	*/
	public void log( File file ) throws Exception {
		PrintWriter out = new PrintWriter( file );
		Set<String> keys = keySet();
		Iterator<String> i = keys.iterator();
		while( i.hasNext() ){
			String key = i.next();
			out.print( key + "=" );
			out.println( getString( get( key ) ) );
		}
                out.flush();
                out.close();
	}
	public LoadRecorder load( File file ) throws Exception {
		Properties pros = new Properties();
                FileInputStream fin = new FileInputStream( file );
		pros.load( fin );
		Enumeration enume = pros.propertyNames();
		while( enume.hasMoreElements() ){
			String name = ( String) enume.nextElement();
			String value = pros.getProperty( name );
			put( name, getList( value ) );
		}
                fin.close();
                
		return this;
	}
}