MicroStream Reference Manual
MicroStream HomeAPI Docs
2.0
2.0
  • Preface
  • System Requirements
  • License
  • Installation
  • Data-Store
    • Overview
    • Getting Started
    • Root Instances
    • Configuration
      • Properties
      • Storage Files and Directories
      • Using Channels
      • Housekeeping
      • Backup
      • Lock File
    • Storing Data
      • Convenience Methods and Explicit Storing (Transactions)
      • Lazy and Eager Storing
      • Transient Fields
      • Best Practice
    • Loading Data
      • Lazy Loading
        • Touched Timestamp, Null-Safe Variant
        • Clearing Lazy References
    • Deleting Data
    • Queries
    • Application Life-Cycle
    • Legacy Type Mapping
      • User Interaction
    • Backup Strategies
    • Import / Export
    • Housekeeping
    • FAQ
      • Data Model
      • Data Management
      • File Storage
      • Miscellaneous
    • Customizing
      • Custom Type Handler
      • Custom Legacy Type Handler
      • PersistenceEagerStoringFieldEvaluator
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  1. Data-Store
  2. Customizing

PersistenceEagerStoringFieldEvaluator

PreviousCustom Legacy Type Handler

Last updated 3 years ago

This is the manual for older MicroStream versions (Version < 5.0).

The new documentation (Version >= 5.0) is located at:

Implementing the PersistenceEagerStoringFieldEvaluator interface allows you to handle the eager/lazy storing behavior of any known member. The default implementation of the MicroStream engine threads all fields as lazy storing. See for details on lazy and eager storing.

The PersistenceEagerStoringFieldEvaluator has only one method to be implemented: public boolean isEagerStoring(Class<?> t, Field u) return true if the field has to be eager, otherwise return false.

public class CustomEagerStoringFieldEvaluator 
	implements PersistenceEagerStoringFieldEvaluator 
{
	@Override
	public boolean isEagerStoring(Class<?> clazz, Field field) 
	{
		if(clazz == MyClass.class && field.getName() == "eagerField")
		{
			return true;
		}
		
		return false;
	}
}

To register the customized PersistenceEagerStoringFieldEvaluator add it using the one.microstream.persistence.types.PersistenceFoundation .setReferenceFieldEagerEvaluator(PersistenceEagerStoringFieldEvaluator) method during the storage initialization.

EmbeddedStorageManager storage = EmbeddedStorage        		
    .Foundation(Storage.ConfigurationBuilder()         				
        .setStorageFileProvider(Storage.FileProvider(WORKINGDIR))         				
        .createConfiguration())
    .onConnectionFoundation(f ->
    {
        f.setReferenceFieldEagerEvaluator(new CustomEagerStoringFieldEvaluator());
    })
    .start(ROOT);

https://docs.microstream.one/
Lazy and Eager Storing