About

Joda-Beans provides a small framework that adds properties to Java, greatly enhancing JavaBeans.

The key concept is to allow each property on a bean to be accessed as an object in its own right. This provides the hook for other technologies to build on, such as serialization, mapping, expression languages and validation.

Joda-Beans is licensed under the business-friendly Apache 2.0 licence.

Features

A selection of key features:

• Code generate mutable and immutable beans
• No more manually written getters, setters, equals, hashCode, toString or immutable builders
• High quality generated code, perfect for use in an API or for creating Javadoc
• Full-featured property abstraction, treating a bean as a map of properties
• Fast, no use of reflection
• Built in JSON, XML and binary serialization

Documentation

Various documentation is available:

• The helpful user guide
• The extended code generation guide
• The Javadoc
• The change notes for each release
• The GitHub source repository
• The related projects including Maven, Gradle and IntelliJ integration

Why Joda Beans?

Joda-Beans has been created to plug a gap in the Java language - properties. The concept of properties is familiar to those coding in almost every other modern language. Java stands alone in its pursuit of the JavaBeans, a specification built on naming conventions and reflection.

JavaBeans are typically created by manual coding or one-off IDE generation, such as by Eclipse. The same approach is taken to the creation of equals and hashCode methods. However, none of these approaches provides for a simple and fast mechanism to query a bean for the properties it exposes.

Joda-Beans provides a solution. As a developer, you just write the fields much as you would today. Then you add annotations to the bean and properties. Finally, you run a code generator, which creates the get/set methods plus framework methods that allow the properties to be effectively queried. A key point is that the code generator may be run again and again on the Java file, and is non-destructive.

  @BeanDefinition
  public final class Foo implements Bean {
    /** The forename. */
    @PropertyDefinition
    private String forename;

    /** The surname. */
    @PropertyDefinition(validate = "notNull")
    private String surname;

    /** The address of the person. */
    @PropertyDefinition
    private Address address;
    
    // Joda-Beans will code generate all getters, setters, equals, hashCode, toString and property accessors
  }

See these sample classes used for testing - a simple user account class, example usage, example of validation.

As well as mutable beans following the Java Bean specification. Joda-Beans supports the creation of immutable beans. One of the biggest issues with using immutable objects in Java is their creation. Joda-Beans simplifies this by code generating builder classes for each immutable bean:

  // using code generated immutable bean builders, example showing an interest rate swap leg
  FixedRateSwapLeg payLeg = FixedRateSwapLeg.builder()
    .accrualPeriods(PeriodicScheduleDefn.builder()
      .startDate(LocalDate.of(2014, 9, 12))
      .endDate(LocalDate.of(2021, 9, 12))
      .frequency(Frequency.P6M)
      .businessDayAdjustment(BusinessDayConventions.MODIFIED_FOLLOWING)
      .startDateBusinessDayAdjustment(BusinessDayAdjustment.NONE)
      .build())
    .calculation(FixedRateCalculation.builder()
      .notional(CurrencyAmount.of(Currency.USD, 100_000_000))
      .dayCount(DayCounts.THIRTY_U_360)
      .rate(0.015)
      .build())
    .build();

Once beans and properties are defined, it is possible to use them in powerful ways. A fast and efficient serialization mechanism is provided to read and write JSON, XML and binary using Joda-Convert for object to string conversion. Further integration is included for MongoDB and Freemarker.