package cn.tendata.jstart.data.domain;

import org.springframework.data.domain.Persistable;

import javax.persistence.Transient;
import java.io.Serializable;

/**
 * Simple interface for entities.
 *
 * @param <ID> the type of the identifier
 * @author Xu Cheng
 */
public abstract class AbstractEntity<ID extends Serializable> implements Persistable<ID>,
	Serializable {

	private static final long serialVersionUID = -7141570524683041372L;

	protected ID id;

	/**
	 * Returns the id of the entity.
	 *
	 * @return the id
	 */
	public ID getId() {
		return id;
	}

	/**
	 * Sets the id of the entity.
	 *
	 * @param id the id to set
	 */
	public void setId(ID id) {
		this.id = id;
	}

	/**
	 * Returns if the entity is new or was persisted already.
	 *
	 * @return if the object is new
	 */
	@Transient
	public boolean isNew() {
		return null == getId();
	}

	/*
	 * (non-Javadoc)
	 *
	 * @see java.lang.Object#toString()
	 */
	@Override
	public String toString() {

		return String.format("Entity of type %s with id: %s", this.getClass().getName(), getId());
	}

	/*
	 * (non-Javadoc)
	 *
	 * @see java.lang.Object#equals(java.lang.Object)
	 */
	@Override
	public boolean equals(Object obj) {

		if (null == obj) {
			return false;
		}

		if (this == obj) {
			return true;
		}

		if (!getClass().equals(obj.getClass())) {
			return false;
		}

		AbstractEntity<?> that = (AbstractEntity<?>) obj;

		return null != this.getId() && this.getId().equals(that.getId());
	}

	/*
	 * (non-Javadoc)
	 *
	 * @see java.lang.Object#hashCode()
	 */
	@Override
	public int hashCode() {

		int hashCode = 17;

		hashCode += null == getId() ? 0 : getId().hashCode() * 31;

		return hashCode;
	}
}