# ElementRecord.java

    package org.codefilarete.stalactite.engine.configurer.elementcollection;

    import org.codefilarete.reflection.PropertyAccessor;
    import org.codefilarete.stalactite.engine.diff.CollectionDiffer;

    /**
     * Represents a line in table storage, acts as a wrapper of element collection with source bean identifier addition.
     *
     * @param <TRGT> raw value type (element collection type)
     * @param <ID> source bean identifier type
     */
    public class ElementRecord<TRGT, ID> {

    	static final PropertyAccessor<ElementRecord<Object, Object>, Object> IDENTIFIER_ACCESSOR = PropertyAccessor.fromMethodReference(
    			ElementRecord::getId,
    			ElementRecord::setId);

    	public static final PropertyAccessor<ElementRecord<Object, Object>, Object> ELEMENT_ACCESSOR = PropertyAccessor.fromMethodReference(
    			ElementRecord::getElement,
    			ElementRecord::setElement);

    	private ID id;
    	private TRGT element;
    	private boolean persisted = false;

    	/**
    	 * Default constructor for select instantiation
    	 */
    	public ElementRecord() {
    	}

    	public ElementRecord(ID id, TRGT element) {
    		setId(id);
    		this.element = element;
    	}

    	public boolean isNew() {
    		return !persisted;
    	}

    	public boolean isPersisted() {
    		return persisted;
    	}

    	public void markAsPersisted() {
    		this.persisted = true;
    	}

    	public ElementRecord<TRGT, ID> setPersisted(boolean persisted) {
    		this.persisted = persisted;
    		return this;
    	}

    	public ID getId() {
    		return id;
    	}

    	public void setId(ID id) {
    		this.id = id;
    		this.persisted = true;
    	}

    	public TRGT getElement() {
    		return element;
    	}

    	public void setElement(TRGT element) {
    		this.element = element;
    	}

    	/**
    	 * Identifier for {@link CollectionDiffer} support (update use case), because it compares beans
    	 * through their "footprint" which is their id in default/entity case, but since we are a value type, we must provide a dedicated footprint.
    	 * Could be hashCode() if it was implemented on identifier + element, but implementing it would require implementing equals() (to comply
    	 * with best practices) which is not our case nor required by {@link CollectionDiffer}.
    	 * Note : name of this method is not important
    	 */
    	public int footprint() {
    		int result = id.hashCode();
    		result = 31 * result + element.hashCode();
    		return result;
    	}
    }