/* 
 * COM1317 Project
 * LockManager class
 * LCB class
 * RCB class
 * Copyright (C) Jing Shan 2003
 */

import java.util.*;

class LockManager{
    private Hashtable locktbl;
    private int TIMEOUT = 2000; 

    LockManager(){
	locktbl = new Hashtable();
    }
   
    public boolean lock(Transaction t, String mode, String resource) throws DeadLockException{

	/* your code goes here */

	return true;
    }

    public boolean unlockAll(Transaction t){
	
	/* your code goes here */

	return true;
    }
   
    private boolean unlock(int id, String resource, LCB l){

	/* your code goes here */
   
	return true;
    }
}


class LCB{
    private int status; /* 0-- granted, 1 -- waiting*/
    private int mode; /* 0-- read, 1 -- write */
    private int Xid;
    private boolean notified;
    private String resource;

    LCB(int stus, int mde, String r, int id){
	status = stus;
	mode = mde;
	Xid = id;
	notified = false;
	resource = r;

	System.out.println();
	System.out.println("create a new LCB: status = "+ status+",  mode ="+mode+"  ,resource= "+resource+",  Xid ="+Xid);
	System.out.println();
    }

    public synchronized void LCBWait(int t){
	try {
	    wait(t);
	}catch (InterruptedException e){
	    System.out.println("interrupted by others:: "+e);
	}
    }
    public synchronized void LCBNotify(){
	notify();
	notified = true;
    }

    public boolean isNotified(){
	return notified;
    }
    public int getStatus(){
	return status;
    }
    public int getMode(){
	return mode;
    }
    public String getResource(){
	return resource;
    }
    public void setMode(int m){
	mode = m;
    }
    public void setStatus(int s){
	status = s;
    }
}

class RCB{
    private String name;//resource name
    private LinkedList lockQueue;
    private int mode; /* 0-- read lock, 1-- write lock*/
    private int status; /* 0-- no wait, 1-- there is at least one LCB waiting */


    RCB(String n){
	name = n;
	lockQueue = new LinkedList();

	System.out.println("create an RCB for resource "+ name);

    }

    public void addRequest(LCB l)
    {
	
	if (lockQueue.size() == 0){
	    mode = l.getMode();
	    status = 0;
	}

	lockQueue.addLast(l);
    }

    public void removeRequest(LCB l){

	if (! (lockQueue.remove(l)))
	    System.out.println("Exception:: LCB"+l+" is not in the lock queue");
    }

    public int getMode(){
	return mode;
    }
    public int getStatus(){
	return status;
    }

    public LinkedList getLockQueue(){
	return lockQueue;
    }

    public int getLockNumber(){
	return lockQueue.size();
    }

    public void setStatus(int i){
	status = i;
    }

    public void setMode(int i){
	mode = i;
    }
    public String name(){
	return name;
    }
    public void print(){
	System.out.println();
	System.out.println("RCB for resource "+name+", lock mode="+ mode+" , status ="+status+"  , number of LCBs in queue="+lockQueue.size());
	System.out.println();
    }
}