io.ebean.bean.MutableValueInfo Maven / Gradle / Ivy
package io.ebean.bean;
/**
* Holds information on mutable values (like plain beans stored as json).
*
* Used internally in EntityBeanIntercept for dirty detection on mutable values.
* Typically, mutation detection is based on a hash/checksum of json content or the
* original json content itself.
*
* Refer to the mapping options {@code @DbJson(mutationDetection)}.
*/
public interface MutableValueInfo {
/**
* Compares the given json returning null if deemed unchanged or returning
* the MutableValueNext to use if deemed dirty/changed.
*
* Returning MutableValueNext allows an implementation based on hash/checksum
* to only perform that computation once.
*
* @return Null if deemed unchanged or the MutableValueNext if deemed changed.
*/
MutableValueNext nextDirty(String json);
/**
* Compares the given object to an internal value.
*
* This is used to support changelog/beanState. The implementation can serialize the
* object into json form and compare it against the original json.
*/
boolean isEqualToObject(Object obj);
/**
* Creates a new instance from the internal json string.
*
* This is used to provide an original/old value for change logging / persist listeners.
* This is only available for properties that have {@code @DbJson(keepSource=true)}.
*/
default Object get() {
return null;
}
}