LogicNot.java

package org.sana.android.procedure.branching;

import java.util.HashMap;

import org.sana.android.procedure.ProcedureElement;
import org.sana.android.procedure.ProcedureParseException;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

import android.util.Log;

/**
 * LogicNot is a Criteria subclass that serves as a container to hold a single
 * Criteria object. It's criteriaMet() method evaluates the Criteria it holds 
 * and returns the opposite (not).
 */
public class LogicNot extends Criteria {
    Criteria criteria;
    
    public LogicNot(Criteria crit) {
        this.criteria = crit;
    }
    
    public boolean criteriaMet() {
    	Log.d(TAG, "criterionMet(): NOT: Begin:");
        boolean result = !criteria.criteriaMet();
    	Log.d(TAG, "criterionMet(): NOT: Result:" + result);
    	return result;
    }
    /**
     * Constructs a negation Criteria from an XML Node
     * @param node The source Node
     * @param elts a list of child criteria
     * @return
     * @throws ProcedureParseException
     */
    public static LogicNot fromXML(Node node, 
    		HashMap<String, ProcedureElement> elts) throws ProcedureParseException 
    {
        if(!node.getNodeName().equals("not"))
            throw new ProcedureParseException("LogicNot got NodeName " 
            		+ node.getNodeName());
        NodeList children = node.getChildNodes();
        if (children.getLength() != 3)
            throw new ProcedureParseException("LogicNot wrong number of "
            		+"elements: expects 1");
        Node child = children.item(1);
        return new LogicNot(Criteria.switchOnCriteria(child, elts));
    }
}