io.oasp.module.jpa.dataaccess.base.AbstractGenericRevisionedDao.java Source code

Introduction

Here is the source code for io.oasp.module.jpa.dataaccess.base.AbstractGenericRevisionedDao.java

Source

/* Copyright (c) The m-m-m Team, Licensed under the Apache License, Version 2.0
 * http://www.apache.org/licenses/LICENSE-2.0 */
package io.oasp.module.jpa.dataaccess.base;

import io.oasp.module.jpa.dataaccess.api.GenericRevisionedDao;
import io.oasp.module.jpa.dataaccess.api.RevisionMetadata;
import io.oasp.module.jpa.dataaccess.api.MutablePersistenceEntity;
import io.oasp.module.jpa.dataaccess.impl.LazyRevisionMetadata;

import java.util.ArrayList;
import java.util.List;

import net.sf.mmm.util.exception.api.ObjectNotFoundException;

import org.hibernate.envers.AuditReader;
import org.hibernate.envers.AuditReaderFactory;

/**
 * This is the abstract base-implementation of a {@link AbstractGenericDao} using {@link org.hibernate.envers
 * Hibernate-Envers} to manage the revision-control.
 *
 * @param <ID> is the type of the {@link MutablePersistenceEntity#getId() primary key} of the managed
 *        {@link MutablePersistenceEntity entity}.
 * @param <ENTITY> is the {@link #getEntityClass() type} of the managed entity.
 *
 * @author hohwille
 */
public abstract class AbstractGenericRevisionedDao<ID, ENTITY extends MutablePersistenceEntity<ID>>
        extends AbstractGenericDao<ID, ENTITY> implements GenericRevisionedDao<ID, ENTITY> {

    /**
     * The constructor.
     */
    public AbstractGenericRevisionedDao() {

        super();
    }

    /**
     * @return the auditReader
     */
    protected AuditReader getAuditReader() {

        return AuditReaderFactory.get(getEntityManager());
    }

    @Override
    public ENTITY load(ID id, Number revision) throws ObjectNotFoundException {

        if (revision == MutablePersistenceEntity.LATEST_REVISION) {
            return find(id);
        } else {
            return loadRevision(id, revision);
        }
    }

    /**
     * This method gets a historic revision of the {@link net.sf.mmm.util.entity.api.GenericEntity} with the given
     * <code>id</code>.
     *
     * @param id is the {@link net.sf.mmm.util.entity.api.GenericEntity#getId() ID} of the requested
     *        {@link net.sf.mmm.util.entity.api.GenericEntity entity}.
     * @param revision is the {@link MutablePersistenceEntity#getRevision() revision}
     * @return the requested {@link net.sf.mmm.util.entity.api.GenericEntity entity}.
     */
    protected ENTITY loadRevision(Object id, Number revision) {

        Class<? extends ENTITY> entityClassImplementation = getEntityClass();
        ENTITY entity = getAuditReader().find(entityClassImplementation, id, revision);
        if (entity != null) {
            entity.setRevision(revision);
        }
        return entity;
    }

    @Override
    public List<Number> getRevisionHistory(ID id) {

        return getAuditReader().getRevisions(getEntityClass(), id);
    }

    @Override
    public List<RevisionMetadata> getRevisionHistoryMetadata(Object id) {

        AuditReader auditReader = getAuditReader();
        List<Number> revisionList = auditReader.getRevisions(getEntityClass(), id);
        List<RevisionMetadata> result = new ArrayList<>();
        for (Number revision : revisionList) {
            Long revisionLong = Long.valueOf(revision.longValue());
            result.add(new LazyRevisionMetadata(getEntityManager(), revisionLong));
        }
        return result;
    }
}