kissonchan / joor

jOOR - Fluent Reflection in Java jOOR is a very simple fluent API that gives access to your Java Class structures in a more intuitive way. The JDK's reflection APIs are hard and verbose to use. Other languages have much simpler constructs to access type meta information at runtime. Let us make Java reflection better.

Overview

jOOR stands for jOOR Object Oriented Reflection. It is a simple wrapper for the java.lang.reflect package.

jOOR's name is inspired by jOOQ, a fluent API for SQL building and execution.

Dependencies

None!

Download

For use with Java 9+

<dependency>
  <groupId>org.jooq</groupId>
  <artifactId>joor</artifactId>
  <version>0.9.7</version>
</dependency>

For use with Java 8+

<dependency>
  <groupId>org.jooq</groupId>
  <artifactId>joor-java-8</artifactId>
  <version>0.9.7</version>
</dependency>

For use with Java 6+

<dependency>
  <groupId>org.jooq</groupId>
  <artifactId>joor-java-6</artifactId>
  <version>0.9.7</version>
</dependency>

Simple example

// All examples assume the following static import:
import static org.joor.Reflect.*;

String world = on("java.lang.String")  // Like Class.forName()
                .create("Hello World") // Call most specific matching constructor
                .call("substring", 6)  // Call most specific matching substring() method
                .call("toString")      // Call toString()
                .get();                // Get the wrapped object, in this case a String

Proxy abstraction

jOOR also gives access to the java.lang.reflect.Proxy API in a simple way:

public interface StringProxy {
  String substring(int beginIndex);
}

String substring = on("java.lang.String")
                    .create("Hello World")
                    .as(StringProxy.class) // Create a proxy for the wrapped object
                    .substring(6);         // Call a proxy method

Comparison with standard java.lang.reflect

jOOR code:

Employee[] employees = on(department).call("getEmployees").get();

for (Employee employee : employees) {
  Street street = on(employee).call("getAddress").call("getStreet").get();
  System.out.println(street);
}

The same example with normal reflection in Java:

try {
  Method m1 = department.getClass().getMethod("getEmployees");
  Employee employees = (Employee[]) m1.invoke(department);

  for (Employee employee : employees) {
    Method m2 = employee.getClass().getMethod("getAddress");
    Address address = (Address) m2.invoke(employee);

    Method m3 = address.getClass().getMethod("getStreet");
    Street street = (Street) m3.invoke(address);

    System.out.println(street);
  }
}

// There are many checked exceptions that you are likely to ignore anyway 
catch (Exception ignore) {

  // ... or maybe just wrap in your preferred runtime exception:
  throw new RuntimeException(e);
}

Similar projects

Everyday Java reflection with a fluent interface:

• http://docs.codehaus.org/display/FEST/Reflection+Module
• http://projetos.vidageek.net/mirror/mirror/

Reflection modelled as XPath (quite interesting!)

• http://commons.apache.org/jxpath/users-guide.html