/***************************************************************************** * net.openai.fsm.Condition ***************************************************************************** * @author  JC on E * @date    9/18/2000 * 2001 OpenAI Labs *****************************************************************************/package net.openai.util.fsm;import java.util.Vector;import java.io.Serializable;/** * This is the base class for all Conditions */public abstract class Condition implements Serializable {    /** A handle to our target State. */    private State targetState;    /** A handle to our source States. */    private Vector sourceStates = new Vector();    /**     * Constructs a new Condition object.     */    public Condition() {    }    /**     * Constructs a new Condition with the given target state.     *     * @param targetState The target state for this Condition.     */    public Condition(State targetState) {	setTargetState(targetState);    }    /**     * Sets the target state for this Condition.  This is the state that     * will be the current state in the machine if this Condition is met.     * <br><br>     * NOTE: If the target state is null whenever this condition is being     *       checked by the machine and it passes, then the result will     *       be an UnhandledConditionException being thrown by the machine.     *       Setting this to null is allowed because it will be necessary     *       within a Graphical Building tool such as bean box or the      *       planned extensions to the net.openai.gui.graph package.     *     * @param targetState The new target state.     */    public final void setTargetState(State targetState) {	this.targetState = targetState;    }    /**     * Returns a handle to this Condition's current target state.     *     * @return This Condition's target state.     */    public final State getTargetState() {	return targetState;    }    /**     * Returns a handle to the source States of this Condition.  The source     * States are the State that will check this Condition to see if it meets     * the criterial passed in and then go on to the target State.     *     * @return The source states of this Condition or null if there are none.     */    public final Vector getSourceStates() {	Vector returnValue = null;	synchronized(sourceStates) {	    returnValue = (Vector)sourceStates.clone();	}	return returnValue;    }    /**     * Adds a source state to this Condition.     *     * @param state The state to add.     */    void addSourceState(State state) {	if(state == null)	    throw new NullPointerException("Cannot add null source state.");	synchronized(sourceStates) {	    if(!sourceStates.contains(state))		sourceStates.addElement(state);	}    }    /**     * Removes a source state from this Condition.     *     * @param state The state to remove.     */    void removeSourceState(State state) {	if(state == null)	    return;	synchronized(sourceStates) {	    sourceStates.removeElement(state);	}    }    /**     * Called to check if the conditional meets the criteria defined by this     * state.  This is the only method to implement in order to used this     * interface.     *     * @param conditional The object to check.     * @return Implementors should return <code>true</code> if this condition     *         is met by the Object <code>conditional</code> and     *         <code>false</code> otherwise.     */    public abstract boolean satisfiedBy(Object conditional);}