package rac;

/**
 * A concrete data node of the internal doubly linked circular list of the RAC.
 * @author S. Wong
 */
public class RACDataNode extends ARACNode {
    private Object data;
    /**
    * Constructor for the RACDataNode.
    * @param data The data to be stored in this node.
    * @param next The node that is the next node in the list.
    * @param previous The node that is the previous node in the list.
    */
    public RACDataNode(Object data, ARACNode next, ARACNode previous) {
        this.data = data;
        this.next = next;
        this.previous = previous;
    }


    /**
    * The visitor design pattern algorithm execution method.   This method will
    * double dispatch to the dataCase() method of the supplied IRACVisitor.
    * @param param A generic parameter to be passed to the algorithm.
    * @param visitor The visitor algorithm to execute.
    * @return The return value of the algorithm.
    */
    public Object execute(IRACVisitor visitor, Object param) {
        return visitor.dataCase(this, param);
    }

    /**
    * Accessor method to get the data object held in this node.
    * @return The data held in this node.
    */
    public Object getData() {
        return data;
    }

    /**
    * Accessor method to set the data in this node.
    * @param data The data to be stored.
    */
    public void setData(Object data) {
        this.data = data;
    }

    /**
    * Removes this node and returns the data object held.
    * @return The data object held in this node.
    */
    public Object removeNode() {
        previous.setNext(next);
        next.setPrevious(previous);
        return data;
    }
}