Handle @EmbeddedId annotation

[giacgbj]

Is there a way to natively handle @EmbeddedId annotation?

I'm currently using the following code to evaluate both @Id and @EmbeddedId annotations:

import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;

import javax.persistence.Embeddable;
import javax.persistence.EmbeddedId;
import javax.persistence.Entity;
import javax.persistence.Id;

import org.apache.commons.lang3.reflect.FieldUtils;

import io.github.classgraph.ClassInfoList;
import nl.jqno.equalsverifier.EqualsVerifier;


final ClassInfoList entities = [OMISSIS];
for (final Class<?> classToCheck : entities.loadClasses()) {
    final List<Field> singleValuePrimaryKeyList = FieldUtils.getFieldsListWithAnnotation(classToCheck, Id.class);
    final List<Field> compositePrimaryKeyList = FieldUtils.getFieldsListWithAnnotation(classToCheck, EmbeddedId.class);
    final List<String> primaryKeyFields = new ArrayList<>();
    primaryKeyFields.addAll(singleValuePrimaryKeyList.stream().map(f -> f.getName()).collect(Collectors.toList()));
    primaryKeyFields.addAll(compositePrimaryKeyList.stream().map(f -> f.getName()).collect(Collectors.toList()));
    EqualsVerifier.forClass(classToCheck).withOnlyTheseFields(primaryKeyFields.toArray(new String[0])).withIgnoredAnnotations(Id.class).verify();

    if (!compositePrimaryKeyList.isEmpty()) {
        final Field compositePKField = compositePrimaryKeyList.get(0);
        final Class<?> compositePKClazz = compositePKField.getType();
        EqualsVerifier.forClass(compositePKClazz).verify();
    }
}

[jqno]

Sure!

Can you give me an example of what a class would look like that uses @EmbeddedId?

Also, should EqualsVerifier handle fields marked with @EmbeddedId in the same way that it handles @Id, or are there differences?

[giacgbj]

The classes would look like this (I omitted all the parts not regarding this specific issue):

@Entity
@Table
public class X {

    @EmbeddedId
    private XCompositePrimaryKey id;

    @Column
    private String value;

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + (id == null ? 0 : id.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null) {
            return false;
        }
        if (!(obj instanceof X)) {
            return false;
        }
        final X other = (X) obj;
        if (id == null) {
            if (other.id != null) {
                return false;
            }
        } else if (!id.equals(other.id)) {
            return false;
        }
        return true;
    }

}

@Embeddable
public class XCompositePrimaryKey {

    @Column
    private String a;

    @Column
    private String b;

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + (b == null ? 0 : b.hashCode());
        result = prime * result + (a == null ? 0 : a.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null) {
            return false;
        }
        if (!(obj instanceof XCompositePrimaryKey)) {
            return false;
        }
        final XCompositePrimaryKey other = (XCompositePrimaryKey) obj;

        if (b == null) {
            if (other.b != null) {
                return false;
            }
        } else if (!b.equals(other.b)) {
            return false;
        }
        if (a == null) {
            if (other.a != null) {
                return false;
            }
        } else if (!a.equals(other.a)) {
            return false;
        }
        return true;
    }

}

Regarding the second question, I probably use it in a different way, as you can see in the code I wrote in the first post: I consider two classes equal if their primary key (single or composite) is equal.

[jqno]

Thanks!
What I meant to ask is, by default EqualsVerifier checks that fields marked with @Id should not be used in equals and hashCode, except when Warning.SURROGATE_KEY is suppressed: in this case it checks that only the fields maeked with @Id are used. Should EqualsVerifier treat @EmbeddedId in the same way? Or is the use case different?

[giacgbj]

Thanks for your prompt answers!

According to your description, I think it should be treated the same way as @Id, so in my case I should add Warning.SURROGATE_KEY to check that only the fields with @Id or @EmbeddedId annotations are used.

[jqno]

OK, thanks for the answer. I'll make EqualsVerifier treat them the same way then. I'm not sure when I can release it but I'll let you know when I do.

[jqno]

I just released version 3.1.4 with support for @EmbeddedId. Please let me know what you think!