/*
 * @(#)file      SnmpLcd.java
 * @(#)author    Sun Microsystems, Inc.
 * @(#)version   1.20
 * @(#)date      06/05/03
 *
 * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 */
package com.sun.jmx.snmp.internal;

import java.util.Hashtable;
import com.sun.jmx.snmp.SnmpEngineId;
import com.sun.jmx.snmp.SnmpUnknownModelLcdException;
import com.sun.jmx.snmp.SnmpUnknownSubSystemException;
/** 
 * Class to extend in order to develop a customized Local Configuration Datastore. The Lcd is used by the <CODE>SnmpEngine</CODE> to store and retrieve data.
 *<P> <CODE>SnmpLcd</CODE> manages the Lcds needed by every {@link com.sun.jmx.snmp.internal.SnmpModel SnmpModel}. It is possible to add and remove {@link com.sun.jmx.snmp.internal.SnmpModelLcd SnmpModelLcd}.</P>
 * <p><b>This API is a Sun Microsystems internal API  and is subject 
 * to change without notice.</b></p>
 * @since 1.5
 */
public abstract class SnmpLcd {

    class SubSysLcdManager {
	private Hashtable models = new Hashtable();
	public void addModelLcd(int id, 
				SnmpModelLcd usmlcd) {
	    models.put(new Integer(id), usmlcd);
	}
	
	public SnmpModelLcd getModelLcd(int id) {
	    return (SnmpModelLcd) models.get(new Integer(id));
	}
	
	public SnmpModelLcd removeModelLcd(int id) {
	    return (SnmpModelLcd) models.remove(new Integer(id));
	}
    }
    

    private Hashtable subs = new Hashtable();
    
    /**
     * Returns the number of time the engine rebooted.
     * @return The number of reboots or -1 if the information is not present in the Lcd.
     */
    public abstract int getEngineBoots();
    /** 
     * Returns the engine Id located in the Lcd.
     * @return The engine Id or null if the information is not present in the Lcd.
     */
    public abstract String getEngineId();
    
    /**
     * Persists the number of reboots.
     * @param i Reboot number.
     */
    public abstract void storeEngineBoots(int i);
    
    /**
     * Persists the engine Id.
     * @param id The engine Id.
     */
    public abstract void  storeEngineId(SnmpEngineId id);
    /**
     * Adds an Lcd model.
     * @param sys The subsytem managing the model.
     * @param id The model Id.
     * @param lcd The Lcd model.
     */
    public void addModelLcd(SnmpSubSystem sys,
			    int id, 
			    SnmpModelLcd lcd) {

	SubSysLcdManager subsys = (SubSysLcdManager) subs.get(sys);
	if( subsys == null ) {
	    subsys = new SubSysLcdManager();
	    subs.put(sys, subsys);
	}
	
	subsys.addModelLcd(id, lcd);
    }
     /**
     * Removes an Lcd model.
     * @param sys The subsytem managing the model.
     * @param id The model Id.
     */
    public void removeModelLcd(SnmpSubSystem sys,
				int id) 
	throws SnmpUnknownModelLcdException, SnmpUnknownSubSystemException {

	SubSysLcdManager subsys = (SubSysLcdManager) subs.get(sys);
	if( subsys != null ) {
	    SnmpModelLcd lcd = subsys.removeModelLcd(id);
	    if(lcd == null) {
		throw new SnmpUnknownModelLcdException("Model : " + id);
	    }
	}
	else
	    throw new SnmpUnknownSubSystemException(sys.toString());
    }

    /**
     * Gets an Lcd model.
     * @param sys The subsytem managing the model
     * @param id The model Id.
     * @return The Lcd model or null if no Lcd model were found.
     */
    public SnmpModelLcd getModelLcd(SnmpSubSystem sys,
				    int id) {
	SubSysLcdManager subsys = (SubSysLcdManager) subs.get(sys);

	if(subsys == null) return null;

	return (SnmpModelLcd) subsys.getModelLcd(id);
    }
}