Java.cs

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using System;
using System.Collections.Generic;
using System.Linq;

namespace CodeGen.generators
{
    public class JavaGenerator : Generator
    {
        private const string ClassFormat = "{0}class {1} {2}{{{3}{4}{5}}}";
        private string Indent { get; } = GeneratorConf.GetIndent(true, 4);

        protected override string GenerateClass(Class @class)
        {
            string access = "", fields = "", inherits = "", methods = "", classes = "";

            if (@class.Parent?.Length > 0)
            {
                inherits = "extends " + @class.Parent + " ";
            }

            fields = @class.Fields?.Aggregate('\n' + fields,
                (current, field) => current + GenerateField(field) + '\n');

            methods = @class.Methods?.Aggregate(methods,
                (current, method) => current + '\n' + GeneratorConf.ShiftCode(GenerateMethod(method), 1, Indent) + '\n');

            classes = @class.Classes?.Aggregate(classes,
                (current, cls) => current + '\n' + GeneratorConf.ShiftCode(GenerateClass(cls), 1, Indent) + '\n');

            if (@class.Access?.Length > 0)
            {
                access = @class.Access + ' ';
            }

            return string.Format(ClassFormat, access, @class.Name, inherits, fields, methods, classes);
        }

        public override string GenerateField(Field field)
        {
            if (!new JavaValidator().FieldIsValid(field))
                throw new ArgumentNullException();

            var result = Indent;
            if (string.IsNullOrWhiteSpace(field.Access) || field.Access == "default")
            {
                result += "private ";
            }
            else
            {
                result += field.Access + ' ';
            }

            if (field.Const)
            {
                result += "const ";
            }

            if (field.Static)
            {
                result += "static ";
            }

            result += field.Type + " ";

            result += field.Name;
            if (field.Default?.Length > 0)
            {
                result += " = " + field.Default;
            }

            result += ';';
            return result;
        }

        public override string GenerateMethod(Method method)
        {
            var result = "";
            if (method.Access == "" || method.Access == "default")
            {
                result += "private ";
            }
            else
            {
                result += method.Access + ' ';
            }

            if (method.Static)
            {
                result += "static ";
            }

            result += method.Type + " ";

            result += method.Name;
            result += '(';

            for (var i = 0; i < method.Parameters?.Length; i++)
            {
                var parameter = method.Parameters[i];
                result += parameter.Type + " " + parameter.Name;
                if (i + 1 < method.Parameters.Length)
                {
                    result += ", ";
                }
            }

            result += ") {";

            if (!string.IsNullOrWhiteSpace(method.Type) && method.Type != "void")
            {
                string defaultVal;
                if (JavaNormalizer.BuiltInDefaults.ContainsKey(method.Type))
                {
                    defaultVal = JavaNormalizer.BuiltInDefaults[method.Type];
                }
                else
                {
                    defaultVal = "new " + method.Type + "()";
                }

                result += '\n' + Indent + "return " + defaultVal + ";\n";
            }

            result += '}';
            return result;
        }

        public override string GetIndent()
        {
            return Indent;
        }
    }

    public class JavaNormalizer : Normalizer
    {
        private static Normalizer _singletonInstance = null;
        
        private JavaNormalizer()
        {
        }

        public static readonly Dictionary<string, string> BuiltInDefaults = new Dictionary<string, string>
        {
            {"int", "0"},
            {"double", "0.0"},
            {"char", "'a'"},
            {"boolean", "false"},
            {"String", "\"\""},
        };

        public static Normalizer GetNormalizer()
        {
            return _singletonInstance ?? (_singletonInstance = new JavaNormalizer());
        }

        protected override string NormalizeType(string type)
        {
            if (type == "bool")
                type = "boolean";
            else if (type == "string")
                type = "String";
            else if (type == "float")
                type = "double";
            else if (string.IsNullOrWhiteSpace(type))
                type = "void";

            return type;
        }
    }

    public class JavaValidator : Validator
    {
    }
}