Randomization parameters

The EnhancedRandomBuilder is the main entry point to set all parameters of how Random Beans generate values:

EnhancedRandom random = EnhancedRandomBuilder.aNewEnhancedRandomBuilder()
   .maxCollectionSize(10)
   .maxStringLength(20)
   .charset(forName("UTF-8"))
   .dateRange(today, tomorrow)
   .timeRange(nine, five)
   .scanClasspathForConcreteTypes(true)
   .seed(123L)
   .build();

Setting the seed parameter

The EnhancedRandom API can be configured with a seed option in order to generate the same random instances.

Using the same seed, each run will produce the same value. This feature is useful when you want stable random values across JVM restarts (in tests for instances).

Classpath Scanning

When the target object declares a field of an abstract or interface type, Random Beans will throw an ObjectGenerationException saying that it was unable to create a random instance of the abstract/interface type. The scanClasspathForConcreteTypes parameter tells Random Beans to scan the classpath and look for a concrete subtype of the abstract/interface field. Let's see a quick example:

abstract class Bar {}

class ConcreteBar extends Bar {}

class Foo {
   private Bar bar;
}

Let's try to generate a random instance of Foo:

EnhancedRandom enhancedRandom = EnhancedRandomBuilder.aNewEnhancedRandomBuilder()
   .scanClasspathForConcreteTypes(true)
   .build();
Foo foo = enhancedRandom.nextObject(Foo.class);

In the generated Foo instance, the bar field will be assigned a random instance of the ConcreteBar type. Without setting the scanClasspathForConcreteTypes parameter, Random Beans will throw an ObjectGenerationException