package simpledb.remote;

import simpledb.record.Schema;
import simpledb.query.*;
import java.rmi.RemoteException;
import java.rmi.server.UnicastRemoteObject;

/**
 * The RMI server-side implementation of RemoteResultSet.
 * @author Edward Sciore
 */
@SuppressWarnings("serial")
class RemoteResultSetImpl extends UnicastRemoteObject implements RemoteResultSet {
	private Scan s;
	private Schema sch;
	private RemoteConnectionImpl rconn;

	/**
	 * Creates a RemoteResultSet object.
	 * The specified plan is opened, and the scan is saved.
	 * @param plan the query plan
	 * @param rconn TODO
	 * @throws RemoteException
	 */
	public RemoteResultSetImpl(Plan plan, RemoteConnectionImpl rconn) throws RemoteException {
		s = plan.open();
		sch = plan.schema();
		this.rconn = rconn;
	}

	/**
	 * Moves to the next record in the result set,
	 * by moving to the next record in the saved scan.
	 * @see simpledb.remote.RemoteResultSet#next()
	 */
	public boolean next() throws RemoteException {
		return s.next();
	}

	/**
	 * Returns the integer value of the specified field,
	 * by returning the corresponding value on the saved scan.
	 * @see simpledb.remote.RemoteResultSet#getInt(java.lang.String)
	 */
	public int getInt(String fldname) throws RemoteException {
		fldname = fldname.toLowerCase(); // to ensure case-insensitivity
		return s.getInt(fldname);
	}

	/**
	 * Returns the integer value of the specified field,
	 * by returning the corresponding value on the saved scan.
	 * @see simpledb.remote.RemoteResultSet#getInt(java.lang.String)
	 */
	public String getString(String fldname) throws RemoteException {
		fldname = fldname.toLowerCase(); // to ensure case-insensitivity
		return s.getString(fldname);
	}

	/**
	 * Returns the result set's metadata,
	 * by passing its schema into the RemoteMetaData constructor.
	 * @see simpledb.remote.RemoteResultSet#getMetaData()
	 */
	public RemoteMetaData getMetaData() throws RemoteException {
		return new RemoteMetaDataImpl(sch);
	}

	/**
	 * Closes the result set by closing its scan.
	 * @see simpledb.remote.RemoteResultSet#close()
	 */
	public void close() throws RemoteException {
		s.close();

		// modified for hw9:
		if (rconn.getAutoCommit())
			rconn.commit();
	}
}