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package com.almende.eve.state;


/**
 * @class State
 * 
 * An interface for a state for Eve agents.
 * The state provides general information for the agent (about itself,
 * the environment, and the system configuration), and the agent can store 
 * persistent data in the state. 
 * The state extends a standard Java Map.
 * 
 * Usage:

 *     AgentFactory factory = AgentFactory(config);

 *     State state = new State("agentId");

 *     state.put("key", "value");

 *     System.out.println(state.get("key")); // "value"

 * 
 * @author jos
 */
public abstract class AbstractState implements State {
	protected String agentId = null;

	/**
	 * The implemented classes must have a public constructor
	 */
	public AbstractState () {}

	/**
	 * The implemented classes must have this public constructor with
	 * parameters agentFactory, and agentId
	 */
	public AbstractState (String agentId) {
		this.agentId = agentId;
	}

	/**
	 * Get the agents id
	 * @return agentId
	 */	
	public synchronized String getAgentId() {
		return agentId;
	}
	
	/**
	 * Set the configured agents class.
	 * @return agentType
	 */
	public synchronized void setAgentType(Class agentType) {
		// TODO: dangerous to use a generic state parameter to store the agent class, can be accidentally overwritten 
		put(KEY_AGENT_TYPE, agentType.getName());
	}
	
	/**
	 * Get the configured agents type (the full class path).
	 * @return type
	 * @throws ClassNotFoundException 
	 */
	public synchronized Class getAgentType() throws ClassNotFoundException {
		String agentType = (String) get(KEY_AGENT_TYPE);
		if (agentType == null) {
			// try deprecated "class"
			agentType = (String) get("class");
			if (agentType != null) {
				put(KEY_AGENT_TYPE, agentType);
				remove("class");
			}
		}
		if (agentType != null) {
			return Class.forName(agentType);
		}
		else {
			return null;
		}
	}

	// init and destroy methods
	public abstract void init();     // executed once after the agent is instantiated
	public abstract void destroy();  // executed once before the agent is destroyed
}