package net.fortytwo.ripple.libs.data;
import net.fortytwo.flow.Sink;
import net.fortytwo.ripple.RippleException;
import net.fortytwo.ripple.libs.graph.GraphLibrary;
import net.fortytwo.ripple.model.ModelConnection;
import net.fortytwo.ripple.model.PrimitiveStackMapping;
import net.fortytwo.ripple.model.RippleList;
import net.fortytwo.ripple.model.RippleValue;
/**
* A primitive which consumes two items and produces a Boolean value of true if
* they are equal according to their data types, otherwise false.
*
* @author Joshua Shinavier (http://fortytwo.net)
*/
public class Equal extends PrimitiveStackMapping {
public String[] getIdentifiers() {
return new String[]{
DataLibrary.NS_2013_03 + "equal",
GraphLibrary.NS_2008_08 + "equal",
GraphLibrary.NS_2007_08 + "equal",
GraphLibrary.NS_2007_05 + "equal"};
}
public Equal() throws RippleException {
super();
}
public Parameter[] getParameters() {
return new Parameter[]{
new Parameter("x", null, true),
new Parameter("y", null, true)};
}
public String getComment() {
return "x y => b -- where b is true if x and y are equal, otherwise false";
}
public void apply(final RippleList arg,
final Sink<RippleList> solutions,
final ModelConnection mc) throws RippleException {
RippleList stack = arg;
RippleValue a, b, result;
a = stack.getFirst();
stack = stack.getRest();
b = stack.getFirst();
stack = stack.getRest();
// Note: equals() is not suitable for this operation (for instance,
// it may yield false for RdfValues containing identical
// Literals).
result = mc.valueOf(0 == mc.getComparator().compare(a, b));
solutions.put(stack.push(result));
}
}