README.md

Medivh

A simple, automatic, and flexible method parameter check library for the Java platform.

Documentation

• Getting Started

Motivation

We often need to check the method parameters, especially in remote invocation. This library can save time and effort in this respect, modify the syntax tree at compilation phase by configure annotations, and add parameter validation to method.

Features

• Check whether an object is null.

• Check the size range of basic numeric type (such as int and Integer).

• Check whether a string is blank.

• Check the length range of String or array.

• Check the capacity range of Collection or Map.

• Throw an exception or return data when validated is fails.

Preview

public class MyApp {

    @Throw
    public Boolean run(Args args,
                    @Return("null") @NotBlank String name,
                    @Return("false") @Min(1) int num) {
        System.out.println("process");
        return true;
    }

    class Args {

        @Max(1000) int id;

        @NotBlank String name;

        @Nullable @DecimalMin(-25.02) @DecimalMax(200) Double price;

        @Size(min = 10, max = 10) String[] values;

        @NotNull HashMap<String, Object> param;

        @Size(max = 5) List<String> extra;
    }
}

After compilation, the program will be this.

public class MyApp {
    public MyApp() {
    }

    public Boolean run(MyApp.Args args, String name, int num) {
        if (args == null) {
            throw new IllegalArgumentException("Invalid input parameter, cause args is null");
        } else {
            String mvar_0 = args.invalid0();
            if (mvar_0 != null) {
                throw new IllegalArgumentException("Invalid input parameter, cause " + mvar_0);
            } else if (name == null) {
                return null;
            } else if (isBlank(name)) {
                return null;
            } else if (num < 1) {
                return false;
            } else {
                System.out.println("process");
                return true;
            }
        }
    }

    class Args {
        int id;
        String name;
        Double price;
        String[] values;
        HashMap<String, Object> param;
        List<String> extra;

        Args() {
        }

        public String invalid0() {
            if (this.id > 1000) {
                return "id great than 1000";
            } else if (this.values == null) {
                return "values is null";
            } else if (this.values.length != 10) {
                return "values cannot equals 10";
            } else if (this.param == null) {
                return "param is null";
            } else {
                if (this.price != null) {
                    if (this.price > 200.0D) {
                        return "price great than 200.0";
                    }

                    if (this.price < -25.02D) {
                        return "price less than -25.02";
                    }
                }

                if (this.name == null) {
                    return "name is null";
                } else if (isBlank(this.name)) {
                    return "name is blank";
                } else if (this.extra == null) {
                    return "extra is null";
                } else {
                    return this.extra.size() > 5 ? "extra.size() great than 5" : null;
                }
            }
        }
    }
    
    public static boolean isBlank(String str) {
        int length = str.length();
        if (length == 0) {
            return true;
        } else {
            for(int i = 0; i < length; ++i) {
                char ch = str.charAt(i);
                if (ch != ' ') {
                    return false;
                }
            }
    
            return true;
        }
    }
}