// JDBC RMI -- sample call to the JDBC through RMI

import java.sql.*;
import java.rmi.*;
import java.rmi.server.UnicastRemoteObject;

public class JRImpl extends UnicastRemoteObject implements JR {

	private JRConnection jrc [] = new JRConnection [5];

	/** Default constructor */
	public JRImpl () throws RemoteException {
	}

	/** Method to open a database connection */
	public synchronized int openDatabase()
		throws RemoteException, SQLException, ClassNotFoundException {
		int connectionId;

		// Loop through connection table until an empty slot is found
		for (connectionId = 0; connectionId < jrc.length; connectionId++) {
			if (jrc [connectionId] == null)
				break;
		}

		// If no empty slots found, generate an error
		if (connectionId >= jrc.length) {
			System.out.println("Out of connection objects.");
			return -1;
		}

		// Create a connection for the new process and run it
		jrc [connectionId] = new JRConnection();

		// Call the new connection's method to open a database connection
		jrc[connectionId].openDatabase();

		// return the connection identifier
		return connectionId;
	}

	/** Issue a SQL query with a WHERE clause */
	public void performSearch(int id, String searchString)
		throws RemoteException, SQLException {
		jrc[id].performSearch(searchString);
	}

	/** Fetch the next row from the current query result */
	public String getNextRow(int id) throws RemoteException, SQLException {
		return jrc[id].getNextRow();
	}

	/** Close the database connection */
	public void closeDatabase(int id) throws RemoteException, SQLException {
		jrc[id].closeDatabase();
		jrc[id] = null;
	}
}