Entity.java

package rescuecore2.worldmodel;

import java.util.Set;

import java.io.InputStream;
import java.io.OutputStream;
import java.io.IOException;

/**
   Interface for all objects that live in a WorldModel. Entities are made up of a fixed set of properties. The values of those properties may change but the set of properties may not.
 */
public interface Entity {
    /**
       Add an EntityListener.
       @param l The listener to add.
     */
    void addEntityListener(EntityListener l);

    /**
       Remove an EntityListener.
       @param l The listener to remove.
     */
    void removeEntityListener(EntityListener l);

    /**
       Get the ID of this Entity.
       @return The ID.
    */
    EntityID getID();

    /**
       Get the urn of this Entity.
       @return The type.
     */
    String getURN();

    /**
       Get all the properties that this entity has.
       @return A set of Properties. This will never be null, but may be empty.
     */
    Set<Property> getProperties();

    /**
       Get a property by urn.
       @param urn The urn to look up.
       @return The property with the given urn or null if no such property exists.
    */
    Property getProperty(String urn);

    /**
       Write this Entity to a stream.
       @param out The stream to write to.
       @throws IOException If the write fails.
     */
    void write(OutputStream out) throws IOException;

    /**
       Read this Entity from a stream.
       @param in The stream to read from.
       @throws IOException If the read fails.
     */
    void read(InputStream in) throws IOException;

    /**
       Create a copy of this entity.
       @return A new Entity with the same ID and property values.
     */
    Entity copy();
}