/*

 * Element.java

 *

 * Created on 12. červenec 2006, 14:14

 *

 * To change this template, choose Tools | Template Manager

 * and open the template in the editor.

 */

package org.netbeans.apifest.boolcircuit;

/**

 * Representation of an element in the circuit.

 * The internal behaviour of the element is opaque to the API user, it can only

 * be used as a building block for logical equations, using primitive operation

 * factories and a factory for input pin representation.

 * Elements are chained to create the logical net. The inputs to the net are

 * represented by the elements created by {@link #createInput(boolean[])}

 * factory method.

 */

public abstract class Element {

    /** Creates a new instance of Element */

    private Element() {

    }

    /**

      */

    abstract double evaluate(double[] inputs);

    abstract int maxInput();

    /**

     * Creates an Element representing 2-input AND function.

     *

     */

    public static Element createAnd(final Element source1, final Element source2) {

        return new Element() {

            double evaluate(double[] inputs) {

                return source1.evaluate(inputs) * source2.evaluate(inputs);

            }

            int maxInput() {

                return Math.max(source1.maxInput(), source2.maxInput());

            }

        };

    }

    /**

     * Creates an Element representing 2-input OR function.

     *

     */

    public static Element createOr(final Element source1, final Element source2) {

        return new Element() {

            double evaluate(double[] inputs) {

                double x = source1.evaluate(inputs);

                double y = source2.evaluate(inputs);

                return 1 - (1 - x)*(1-y);

            }

            int maxInput() {

                return Math.max(source1.maxInput(), source2.maxInput());

            }

        };

    }

    /**

     * Creates an Element representing negation.

     *

     */

    public static Element createNot(final Element source1) {

        return new Element() {

            double evaluate(double[] inputs) {

                return 1 - source1.evaluate(inputs);

            }

            int maxInput() {

                return source1.maxInput();

            }

        };

    }

    /**

     * Creates an Element representing input to the logical net.

     *

     */

    public static Element createInput(final int pin) {

        return new Element() {

            double evaluate(double[] inputs) {

                return inputs[pin];

            }

            int maxInput() {

                return pin;

            }

        };

    }

    // BEGIN: apifest.day2.pinbasedsolution.FunctionFactory

    /**

     * Creates an Element with user-defined transfer function.

     */

    public static Element createGate(final Element source1, final Element source2, final Function function) {

        return new Element() {

            double evaluate(double[] inputs) {

                double x = source1.evaluate(inputs);

                double y = source2.evaluate(inputs);

                double result = function.evaluate(x, y);

                if (result < 0.0 || result > 1.0) throw new InternalError("Illegal gate function");

                return result;

            }

            int maxInput() {

                return Math.max(source1.maxInput(), source2.maxInput());

            }

        };

    }

    // END: apifest.day2.pinbasedsolution.FunctionFactory

}