ImmutableJsonb

ImmutableJsonb is zero runtime dependencies utility library that generates Jsonb immutable classes using the Immutables.org library.

Requirements

Include the Eclipse JakartaEE 8.0.0 (that includes `Jsonb`) dependency with provided scope (if not present):

<dependency>
    <groupId>jakarta.platform</groupId>
    <artifactId>jakarta.jakartaee-api</artifactId>
    <version>8.0.0</version>
    <scope>provided</scope>
</dependency>

Include the `Immutables` dependency with provided scope:

<dependency>
    <groupId>org.immutables</groupId>
    <artifactId>value</artifactId>
    <version>2.8.0</version>
    <scope>provided</scope>
</dependency>

Include the `ImmutablesJsonb` dependency with provided scope:

<dependency>
    <groupId>com.github.cchacin</groupId>
    <artifactId>immutables-jsonb</artifactId>
    <version>LATEST</version>
    <scope>provided</scope>
</dependency>

How to use it

Create an abstract class
Annotated the class with @ImmutableJsonb
Add a default constructor annotated with @JsonbCreator
Add the abstract getters
That’s it! Enjoy

@ImmutableJsonb
public abstract class MyPojo {

    @JsonbCreator
    public MyPojo() {
    }

    @JsonbProperty("anotherNameForField")
    public abstract Double getField();
    
    // rest of the getters omitted
}

What do you get?

From the immutables library

Java annotation processors to generate simple, safe and consistent value objects. Do not repeat yourself, try Immutables, the most comprehensive tool in this field!

Builder

/**
 * Builds instances of type {@link MyPojoInternalBuilder.ImmutableMyPojo ImmutableMyPojo}.
 * Initialize attributes and then invoke the {@link #build()} method to create an
 * immutable instance.
 * <p><em>{@code MyPojoInternalBuilder} is not thread-safe and generally should not be stored in a field or collection,
 * but instead used immediately to create instances.</em>
 */
@Generated(from = "MyPojo", generator = "Immutables")
@SuppressWarnings({"all"})
@javax.annotation.Generated("org.immutables.processor.ProxyProcessor")
public final class MyPojoInternalBuilder {
  private Double getDouble;
  /**
   * Creates a builder for {@link MyPojoInternalBuilder.ImmutableMyPojo ImmutableMyPojo} instances.
   * <pre>
   * new MyPojoInternalBuilder()
   *    .getDouble(Double | null) // nullable {@link MyPojo#getDouble() double}
   *    .build();
   * </pre>
   */
  public MyPojoInternalBuilder() {
  }
  /**
   * Fill a builder with attribute values from the provided {@code MyPojo} instance.
   * Regular attribute values will be replaced with those from the given instance.
   * Absent optional values will not replace present values.
   * @param instance The instance from which to copy values
   * @return {@code this} builder for use in a chained invocation
   */
  public final MyPojoInternalBuilder from(MyPojo instance) {
    Objects.requireNonNull(instance, "instance");
    Double getDoubleValue = instance.getDouble();
    if (getDoubleValue != null) {
      getDouble(getDoubleValue);
    }
    return this;
  }
  /**
   * Initializes the value for the {@link MyPojo#getDouble() double} attribute.
   * @param getDouble The value for getDouble (can be {@code null})
   * @return {@code this} builder for use in a chained invocation
   */
  public final MyPojoInternalBuilder getDouble(Double getDouble) {
    this.getDouble = getDouble;
    return this;
  }

  /**
   * Builds a new {@link MyPojoInternalBuilder.ImmutableMyPojo ImmutableMyPojo}.
   * @return An immutable instance of MyPojo
   * @throws java.lang.IllegalStateException if any required attributes are missing
   */
  public ImmutableMyPojo build() {
    return new MyPojoInternalBuilder.ImmutableMyPojo(getDouble);
  }
}

Generated Immutable implementation class nested in builder

/**
 * Immutable implementation of {@link MyPojo}.
 * <p>
 * Use the builder to create immutable instances:
 * {@code new MyPojoInternalBuilder()}.
 * Use the static factory method to create immutable instances:
 * {@code new MyPojoInternalBuilder.ImmutableMyPojo()}.
 */
@Generated(from = "MyPojo", generator = "Immutables")
public static final class ImmutableMyPojo extends MyPojo { 
    private final Double getDouble;

    /**
     * Construct a new immutable {@code MyPojo} instance.
     * @param getDouble The value for the {@code getDouble} attribute, can be {@code null}
     */
    @JsonbCreator
    public ImmutableMyPojo(@JsonbProperty("anotherNameForDouble") Double getDouble) {
      this.getDouble = getDouble;
    }

    /**
     * @return The value of the {@code getDouble} attribute
     */
    @JsonbProperty("anotherNameForDouble")
    @Override
    public Double getDouble() {
      return getDouble;
    }

    /**
     * Copy the current immutable object by setting a value for the {@link MyPojo#getDouble() double} attribute.
     * An equals check used to prevent copying of the same value by returning {@code this}.
     * @param value A new value for getDouble (can be {@code null})
     * @return A modified copy of the {@code this} object
     */
    public final MyPojoInternalBuilder.ImmutableMyPojo withDouble(Double value) {
      if (Objects.equals(this.getDouble, value)) return this;
      return new MyPojoInternalBuilder.ImmutableMyPojo(value);
    }

    /**
     * This instance is equal to all instances of {@code ImmutableMyPojo} that have equal attribute values.
     * @return {@code true} if {@code this} is equal to {@code another} instance
     */
    @Override
    public boolean equals(Object another) {
      if (this == another) return true;
      return another instanceof MyPojoInternalBuilder.ImmutableMyPojo
          && equalTo((MyPojoInternalBuilder.ImmutableMyPojo) another);
    }

    private boolean equalTo(MyPojoInternalBuilder.ImmutableMyPojo another) {
      return Objects.equals(getDouble, another.getDouble);
    }

    /**
     * Computes a hash code from attributes: {@code getDouble}.
     * @return hashCode value
     */
    @Override
    public int hashCode() {
      int h = 5381;
      h += (h << 5) + Objects.hashCode(getDouble);
      return h;
    }

    /**
     * Prints the immutable value {@code MyPojo} with attribute values.
     * @return A string representation of the value
     */
    @Override
    public String toString() {
      return "MyPojo{"
          + "double=" + getDouble
          + "}";
    }

    /**
     * Creates an immutable copy of a {@link MyPojo} value.
     * Uses accessors to get values to initialize the new immutable instance.
     * If an instance is already immutable, it is returned as is.
     * @param instance The instance to copy
     * @return A copied immutable MyPojo instance
     */
    public static MyPojoInternalBuilder.ImmutableMyPojo copyOf(MyPojo instance) {
      if (instance instanceof MyPojoInternalBuilder.ImmutableMyPojo) {
        return (MyPojoInternalBuilder.ImmutableMyPojo) instance;
      }
      return new MyPojoInternalBuilder()
          .from(instance)
          .build();
    }
}