Guavapt

Guavapt is Guava Functional Idioms support with APT.

Motivation

Funcito is so cool! However Funcito does not support final classes.

Since we want to use @Value annotation of Lombok, we create guavapt.

Usage

Add @Guavapt annotation into your bean class.

package my.cool.lib;

import java.util.List;
import jp.t2v.guavapt.Guavapt;

@Guavapt
public class Company {

    private final int id;
    private final String name;
    private final List<Employee> employees;
    private final boolean listed;

    public Company(int id, String name, List<Employee> employees, boolean listed) {
        this.id = id;
        this.name = name;
        this.employees = employees;
        this.listed = listed;
    }

    public int getId() { return id; }
    public String getName() { return name; }
    public List<Employee> getEmployees() { return employees; }
    public boolean isListed() { return listed; }

    public boolean hasEmployee() { return !employees.isEmpty(); }
}

You can use Functions and Predicates as follows.

  List<Company> companies = ...

  List<Integer> listedCompanyIds = FluentIterable.from(companies)
      .filter(CompanyPredicates.isListed)
      .transform(CompanyFunctions.getId)
      .toList();

Generated files.

package my.cool.lib;

import com.google.common.base.Function;

public class CompanyFunctions {
    private CompanyFunctions() {}
    public static final Function<Company, java.lang.Integer> getId = new Function<Company, java.lang.Integer>() {
        @Override
        public java.lang.Integer apply(final Company input) {
            return input.getId();
        }
    };
    public static final Function<Company, java.lang.String> getName = new Function<Company, java.lang.String>() {
        @Override
        public java.lang.String apply(final TestEntity input) {
            return input.getName();
        }
    };
    public static final Function<Company, java.util.List<my.cool.lib.Employee>> getEmployees = new Function<Company, java.util.List<my.cool.lib.Employee>>() {
        @Override
        public java.util.List<my.cool.lib.Employee> apply(final Company input) {
            return input.getEmployees();
        }
    };
    public static final Function<Company, java.lang.Boolean> isListed = new Function<Company, java.lang.Boolean>() {
        @Override
        public java.lang.Boolean apply(final Company input) {
            return input.isListed();
        }
    };
    public static final Function<Company, java.lang.Boolean> hasEmployee = new Function<Company, java.lang.Boolean>() {
        @Override
        public java.lang.Boolean apply(final Company input) {
            return input.hasEmployee();
        }
    };
}

and

package my.cool.lib;

import com.google.common.base.Predicate;

public class CompanyPredicates {
    private CompanyPredicates() {}
    public static final Predicate<Company> isListed = new Predicate<Company>() {
        @Override
        public boolean apply(final Company input) {
            return input.isListed();
        }
    };
    public static final Predicate<Company> hasEmployee = new Predicate<Company>() {
        @Override
        public boolean apply(final Company input) {
            return input.hasEmployee();
        }
    };
}

Control generation

@Guavapt annotation can take parametes.

@Guavapt(functions = true, predicates = false)

When functions is true, Guavapt generate functions class.

When predicates is true, Guavapt generate predicates class.

Customize class name

You can change class name suffix of generated class.

add guavapt.f.suffix or guavapt.p.suffix processor options.

for example

javac -cp guavapt.jar -s -Aguavapt.f.suffix=Foo -Aguavapt.p.suffix=Bar my/cool/lib/Company.java

Gavapt generate CompanyFoo and CompanyBar insted of CompanyFunctions and CampanyPredicates

License

This library is released under the Apache Software License, version 2, which should be included with the source in a file named LICENSE.