EclipseのSpark Builder Generatorプラグインによるbuilder生成

Spark Builder GeneratorというEclipseプラグインでいわゆるbuilderパターンのコードが生成できる、とのこと。とりあえず使ってみる。

Generate regular builder

import javax.annotation.Generated;

public class Person {
    private String firstName;

    private String middleName;

    private String lastName;

    private String city;

    private String jobTitle;

    @Generated("SparkTools")
    private Person(Builder builder) {
        this.firstName = builder.firstName;
        this.middleName = builder.middleName;
        this.lastName = builder.lastName;
        this.city = builder.city;
        this.jobTitle = builder.jobTitle;
    }

    /**
     * Creates builder to build {@link Person}.
     * @return created builder
     */
    @Generated("SparkTools")
    public static Builder builder() {
        return new Builder();
    }

    /**
     * Builder to build {@link Person}.
     */
    @Generated("SparkTools")
    public static final class Builder {
        private String firstName;
        private String middleName;
        private String lastName;
        private String city;
        private String jobTitle;

        private Builder() {
        }

        public Builder withFirstName(String firstName) {
            this.firstName = firstName;
            return this;
        }

        public Builder withMiddleName(String middleName) {
            this.middleName = middleName;
            return this;
        }

        public Builder withLastName(String lastName) {
            this.lastName = lastName;
            return this;
        }

        public Builder withCity(String city) {
            this.city = city;
            return this;
        }

        public Builder withJobTitle(String jobTitle) {
            this.jobTitle = jobTitle;
            return this;
        }

        public Person build() {
            return new Person(this);
        }
    }


}

使うときはこんな感じ。

Person person = Person.builder()
    .withCity("city")
    .withFirstName("firstName")
    .build();

Generate staged builder

なんか選択画面が出てくる。

public class Person2 {
    private String firstName;

    private String middleName;

    private String lastName;

    private String city;

    private String jobTitle;

    @Generated("SparkTools")
    private Person2(Builder builder) {
        this.firstName = builder.firstName;
        this.middleName = builder.middleName;
        this.lastName = builder.lastName;
        this.city = builder.city;
        this.jobTitle = builder.jobTitle;
    }

    /**
     * Creates builder to build {@link Person2}.
     * @return created builder
     */
    @Generated("SparkTools")
    public static IFirstNameStage builder() {
        return new Builder();
    }

    @Generated("SparkTools")
    public interface IFirstNameStage {
        public IMiddleNameStage withFirstName(String firstName);
    }

    @Generated("SparkTools")
    public interface IMiddleNameStage {
        public ILastNameStage withMiddleName(String middleName);
    }

    @Generated("SparkTools")
    public interface ILastNameStage {
        public ICityStage withLastName(String lastName);
    }

    @Generated("SparkTools")
    public interface ICityStage {
        public IJobTitleStage withCity(String city);
    }

    @Generated("SparkTools")
    public interface IJobTitleStage {
        public IBuildStage withJobTitle(String jobTitle);
    }

    @Generated("SparkTools")
    public interface IBuildStage {
        public Person2 build();
    }

    /**
     * Builder to build {@link Person2}.
     */
    @Generated("SparkTools")
    public static final class Builder
            implements IFirstNameStage, IMiddleNameStage, ILastNameStage, ICityStage, IJobTitleStage, IBuildStage {
        private String firstName;
        private String middleName;
        private String lastName;
        private String city;
        private String jobTitle;

        private Builder() {
        }

        @Override
        public IMiddleNameStage withFirstName(String firstName) {
            this.firstName = firstName;
            return this;
        }

        @Override
        public ILastNameStage withMiddleName(String middleName) {
            this.middleName = middleName;
            return this;
        }

        @Override
        public ICityStage withLastName(String lastName) {
            this.lastName = lastName;
            return this;
        }

        @Override
        public IJobTitleStage withCity(String city) {
            this.city = city;
            return this;
        }

        @Override
        public IBuildStage withJobTitle(String jobTitle) {
            this.jobTitle = jobTitle;
            return this;
        }

        @Override
        public Person2 build() {
            return new Person2(this);
        }
    }


}

使うときはこんな感じ。

Person2 person2 = Person2.builder()
    .withFirstName("firstName")
    .withMiddleName("middleName")
    .withLastName("lastName")
    .withCity("city")
    .withJobTitle("jobTitle")
    .build();

設定

なんか色々設定できる（ぜんぜん試してない）