hibernate-demo/src/main/java/com/ankurm/hibernatedemo/persistenceannotations/MixedAccessEntity.java

package com.ankurm.hibernatedemo.persistenceannotations;

import jakarta.persistence.Access;
import jakarta.persistence.AccessType;
import jakarta.persistence.Column;
import jakarta.persistence.Entity;
import jakarta.persistence.GeneratedValue;
import jakarta.persistence.Id;
import jakarta.persistence.Transient;

/**
 * Default access is FIELD (because {@code @Id} is annotated on the field). One property,
 * {@code computedLabel}, is explicitly switched to PROPERTY access via {@code @Access} on its
 * getter, with a derivation the FIELD side does not know about. This reproduces the classic
 * "mixed access silently reads the wrong value" symptom: a raw field mutation is invisible to
 * Hibernate once a property is PROPERTY-access, and vice versa.
 *
 * <p>Docs: docs/05-jpa-persistence-annotations.md, Topic 2.
 */
@Entity
public class MixedAccessEntity {

    @Id
    @GeneratedValue
    private Long id;

    private String rawValue;

    // FIELD access is the entity default (because @Id is on a field). This backing field is
    // deliberately never read directly by Hibernate for the "label" property -- only the
    // PROPERTY-access getter below is.
    @Transient
    private int getterCallCount = 0;

    public MixedAccessEntity() {
    }

    public MixedAccessEntity(String rawValue) {
        this.rawValue = rawValue;
    }

    public Long getId() {
        return id;
    }

    public String getRawValue() {
        return rawValue;
    }

    public void setRawValue(String rawValue) {
        this.rawValue = rawValue;
    }

    /**
     * Explicitly PROPERTY access: Hibernate calls this getter (not a field read) to determine
     * the persisted value for the "computedLabel" mapped property.
     */
    @Access(AccessType.PROPERTY)
    @Column(name = "computed_label")
    public String getComputedLabel() {
        getterCallCount++;
        return rawValue == null ? null : rawValue.toUpperCase();
    }

    // Hibernate's default PROPERTY-access strategy REQUIRES a setter even for a logically
    // read-only derived column -- omitting it throws PropertyNotFoundException at boot
    // ("Could not locate setter method for property 'computedLabel'"). This setter is a
    // deliberate no-op: it exists purely to satisfy that requirement.
    public void setComputedLabel(String ignored) {
        // no-op: computedLabel is derived from rawValue, never written directly
    }

    public int getGetterCallCount() {
        return getterCallCount;
    }
}