book.java

线程通信

import java.util.*;
public class Book extends StringAdapter{
	static int Id=0;
	
	private String title;
	private int id=Id++;
	private int borrower=-1;//borrower id
	private boolean available=true;
	
	
	public Book(String title){
		this.title=title;
	}
	
	/*return whether borrow is sucessful*/
	public synchronized boolean borrow(int borrower){
		if(available==false)
			return false;
		else{	
			this.borrower=borrower;
			available=false;
			return true;
		}
	}
	
	/*return whether retun is sucessful*/
	public synchronized boolean retun(int borrower){
			if(borrower!=this.borrower)
				return false;
			else{
				this.borrower=-1;
				available=true;
				return true;
			}
		
	}
	
	public synchronized boolean isAvaliable(){
		return available;
	}
	
	public synchronized String toString(){
		return (adapt(id,25)+adapt(title,25)+adapt(borrower,25));
	}
	
	public String getTitle(){
		return title;
	}
	
	public String getId(){
		return Integer.toString(id);
	}
	
	public  synchronized int getBorrower(){
		return borrower;
	}
}