francofabio / sjog

Simple Java Object-Graph

Simple Java Object-Graph

This project is intended to help developers who need to dynamically access properties in Java objects through simple expressions based on string.

How to use

To use this library, you need install the package in your maven local repository:

mvn install

And add this dependency in your pom.xml

<dependency>
    <groupId>br.com.binarti</groupId>
    <artifactId>sjog</artifactId>
    <version>1.1.0</version> <!-- or the last version -->
</dependency>

This library is not available yet in maven central repository, it is coming soon.
If you not use maven. You can also build the jar and add in classpath of the Java app.
To build jar package, you need install maven and execute the command:

mvn clean package

The jar package is available in target/ directory.

Java 1.8 is required

Quick start

The 'default object graph predicate' automatically include all properties of the types in object graph:
byte, short, int, long, float, double, boolean, char, java.lang.String, java.lang.Enum, java.util.Date, java.util.Calendar

import br.com.binarti.sjog.ObjectGraphBuilder;
...
private static class Person {
    private String name;
    private int age;
    //getters and setters omitted
}

ObjectGraph objectGraph = new ObjectGraphBuilder()
        .build(new Person("John Galt", 43);
String name = (String) objectGraph.get("name"); //get name property value by name
Integer age = (Integer) objectGraph.get("age"); //get age property value by name

In the above example, an object graph was created to enable access the properties of the person object by the name.

Nested properties

import br.com.binarti.sjog.ObjectGraphBuilder;
...

private static class Order {
  private int id;
  private Person customer;
  private Date date;
  private double amount;
  private List<Item> itens;
  //constructors, getters and setters are omitted
}
private static class Item {
  private int id;
  private String productName;
  //constructors, getters and setters are omitted
}
Order order = new Order(129, new Person("Kane"), new Date(), 1650d);
order.addItem(new Item(1, "MacBook pro 13"));
order.addItem(new Item(2, "iPad Air 2"));
ObjectGraph orderObjectGraph = new ObjectGraphBuilder()
        .include("customer") //include all properties of the java basic type presents in customer object
        .include("itens") //include all properties of the java basic type presents in itens (considering generic type of the collection or the collection content)
        .build(order);
Integer orderId = orderObjectGraph.get("id"); //get id property of the order
String customerName = orderObjectGraph.get("customer.name"); //get the name of the customer in order
String firstProductName = orderObjectGraph.get("itens[0].productName"); //get the product name of the first item in collection itens