Designing classes - Objects First with Java: A Practical Introduction Using BlueJ - page 210

Code 6.5
continued
Source code of the
Room class

public Room(String description)
{

this .description = description;
exits = new HashMap<String, Room>();

}

/**
* Define the exits of this room. Every direction either
* leads to another room or is null (no exit there).
*/
public void setExits(Room north, Room east, Room south,
Room west)
{

if (north != null )
exits.put( "north" , north);
if (east != null )
exits.put( "east" , east);
if (south != null )
exits.put( "south" , south);
if (west != null )
exits.put( "west" , west);

}

/**
* Return the room that is reached if we go from this
* room in direction "direction "If there is no room in
* that direction, return null.
*/
public Room getExit(String direction)
{

return exits.get(direction);

}

/**
* Return the description of the room (the one that was
* defined in the constructor).
*/
public String getDescription()
{

return description;

}

}