/*
 * @(#)AbstractConnector.java
 *
 * Project:		JHotdraw - a GUI framework for technical drawings
 *				http://www.jhotdraw.org
 *				http://jhotdraw.sourceforge.net
 * Copyright:	© by the original author(s) and all contributors
 * License:		Lesser GNU Public License (LGPL)
 *				http://www.opensource.org/licenses/lgpl-license.html
 */

package org.jhotdraw.standard;

import java.awt.*;
import java.io.IOException;
import org.jhotdraw.framework.*;
import org.jhotdraw.util.*;

/**
 * AbstractConnector provides default implementation for
 * the Connector interface.
 *
 * @see Connector
 *
 * @version <$CURRENT_VERSION$>
 */
public abstract class AbstractConnector implements Connector {
	/**
	 * the owner of the connector
	 */
	private Figure      fOwner;

	/*
	 * Serialization support.
	 */
	private static final long serialVersionUID = -5170007865562687545L;
	private int abstractConnectorSerializedDataVersion = 1;

	/**
	 * Constructs a connector that has no owner. It is only
	 * used internally to resurrect a connectors from a
	 * StorableOutput. It should never be called directly.
	 */
	public AbstractConnector() {
		fOwner = null;
	}

	/**
	 * Constructs a connector with the given owner figure.
	 */
	public AbstractConnector(Figure owner) {
		fOwner = owner;
	}

	/**
	 * Gets the connector's owner.
	 * Which is the figure this is attached too and NOT the connection it may be
	 * attached too.
	 *
	 */
	public Figure owner() {
		return fOwner;
	}

	public Point findStart(ConnectionFigure connection) {
		return findPoint(connection);
	}

	public Point findEnd(ConnectionFigure connection) {
		return findPoint(connection);
	}

	/**
	 * Gets the connection point. Override when the connector
	 * does not need to distinguish between the start and end
	 * point of a connection.
	 */
	protected Point findPoint(ConnectionFigure connection) {
		return Geom.center(displayBox());
	}

	/**
	 * Gets the display box of the connector.
	 */
	public Rectangle displayBox() {
		return owner().displayBox();
	}

	/**
	 * Tests if a point is contained in the connector.
	 */
	public boolean containsPoint(int x, int y) {
		return owner().containsPoint(x, y);
	}

	/**
	 * Draws this connector. By default connectors are invisible.
	 */
	public void draw(Graphics g) {
		// invisible by default
	}

	/**
	 * Stores the connector and its owner to a StorableOutput.
	 */
	public void write(StorableOutput dw) {
		dw.writeStorable(owner());
	}

	/**
	 * Reads the connector and its owner from a StorableInput.
	 */
	public void read(StorableInput dr) throws IOException {
		fOwner = (Figure)dr.readStorable();
	}

	/**
	 * Requests that the connector should show itself or hide itself.  The
	 * ConnectionFigure which desires to connect to this Connector is passed in.
	 * It a connector should show itself it should do so when draw is called, if
	 * so desired.
	 */
	public void connectorVisibility(boolean isVisible, ConnectionFigure courtingConnection) {
		//invisible by default
	}
}