Class Functions

MathParser/src/com/aghajari/math/Functions.java:33–478

import java.util.regex.Matcher;

public class Functions {

    /**
     * All static methods in {@link Math} and {@link Functions}
     * that returns double and matches arguments will wrap a {@link MathFunction}
     * by {@link MathFunction#wrap(Method)} and import here so
     * the MathParser can recognize the functions as a built-in function.
     */
    private static final List<MathFunction> functions = new ArrayList<>();

    static {
        functions.add(new LogFunction());
        functions.add(new RadicalFunction());
        try {
            functions.add(MathFunction.wrap(Functions.class.getMethod("integral", MathParser.class,
                    String.class, String.class, double.class, double.class), "∫"));
            functions.add(MathFunction.wrap(Functions.class.getMethod("integral", MathParser.class,
                    String.class, String.class, double.class, double.class, double.class), "∫"));
            functions.add(MathFunction.wrap(Functions.class.getMethod("radical",
                    double.class), "√"));
            functions.add(MathFunction.wrap(Functions.class.getMethod("sigma", MathParser.class, String.class,
                    String.class, double.class, double.class), "Σ"));
            functions.add(MathFunction.wrap(Functions.class.getMethod("sigma", MathParser.class, String.class,
                    String.class, double.class, double.class, double.class), "Σ"));
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        }

        ArrayList<Method> methods = new ArrayList<>();
        methods.addAll(Arrays.asList(Functions.class.getMethods()));
        methods.addAll(Arrays.asList(Math.class.getMethods()));
        addFunctions(methods, functions);
    }

    public static List<MathFunction> getFunctions() {
        return functions;
    }

    static void addFunctions(Collection<Method> methods, List<MathFunction> functions) {
        Math:
        for (Method method : methods) {
            if (method.getReturnType() == double.class) {
                if (method.getParameterCount() != 1 ||
                        (method.getParameterTypes()[0] != Object[].class && method.getParameterTypes()[0] != Double[].class)) {
                    int index = 0;
                    for (Class<?> cls : method.getParameterTypes()) {
                        if (cls != double.class && cls != String.class && !(index == 0 && cls == MathParser.class))
                            continue Math;
                        index++;
                    }
                }
                functions.add(MathFunction.wrap(method));
            }
        }
    }

    static MathFunction getFunction(String src, int index, String name, int count, List<MathFunction> innerFunctions) throws MathFunctionInvalidArgumentsException {
        MathFunction function = null;