EDIT

/**

* Copyright (C) 2007 EDIT

* European Distributed Institute of Taxonomy

* http://www.e-taxonomy.eu

*

* The contents of this file are subject to the Mozilla Public License Version 1.1

* See LICENSE.TXT at the top of this package for the full license terms.

*/

package eu.etaxonomy.cdm.model.common;

import java.util.HashSet;

import java.util.Set;

import javax.persistence.MappedSuperclass;

import javax.persistence.Transient;

import javax.xml.bind.annotation.XmlAccessType;

import javax.xml.bind.annotation.XmlAccessorType;

import javax.xml.bind.annotation.XmlAttribute;

import javax.xml.bind.annotation.XmlEnum;

import javax.xml.bind.annotation.XmlEnumValue;

import javax.xml.bind.annotation.XmlRootElement;

import javax.xml.bind.annotation.XmlTransient;

import javax.xml.bind.annotation.XmlType;

import org.apache.log4j.Logger;

import org.hibernate.envers.Audited;

import eu.etaxonomy.cdm.model.reference.Reference;

/**

 * Concrete implementations of this abstract base class express a directed relationship between two

 * cdm entities ( {@link IRelated} ). The most important properties of the relationship are:

 * <ul>

 * <li>{@link #getRelatedFrom(IRelated)}</li>

 * <li>{@link #getRelatedTo(IRelated)}</li>

 * <li>The {@code <TYPE>}, a RelationshipTermBase which specifies the kind of the relationship</li>

 * </ul>

 * A relationship thus is forming a directed graph consisting of two nodes and an edge:

 * <pre>

     relatedFrom -----[TYPE]----> relatedTo

   </pre>

 * Whereas the direction of the relation can be valid for the direct (everted) and also for the inverted {@link Direction} direction.

 * This directional validity is defined by {@link RelationshipTermBase#isSymmetric()}

 *

 *

 *

 * @author m.doering

 * @author a.kohlbecker (Documentation)

 */

@XmlAccessorType(XmlAccessType.FIELD)

@XmlType(name = "RelationshipBase")

@XmlRootElement(name = "RelationshipBase")

@MappedSuperclass

@Audited

public abstract class RelationshipBase<FROM extends IRelated, TO extends IRelated, TYPE extends RelationshipTermBase> extends ReferencedEntityBase implements Cloneable {

    private static final long serialVersionUID = -5030154633820061997L;

    @SuppressWarnings("unused")

    private static final Logger logger = Logger.getLogger(RelationshipBase.class);

    @XmlAttribute(name = "isDoubtful")

    private boolean doubtful;

    //this set is used only for persistence (CdmDeleteListener) to delete safely relationships and update their former related objects

    @XmlTransient

    @Transient

    protected Set<IRelated> deletedObjects = new HashSet<IRelated>();

    /**

     * Enumeration and String representation of the <code>relatedFrom</code> (invers) and

     * <code>relatedTo</code> (direct, everted) bean properties. Intended to be used in the

     * persistence layer only.( But also used in the service layer now - a.kohlbecker )

     *

     * See also {@link RelationshipBase} for an explanation on relationships in general.

     */

    @XmlEnum

    public enum Direction {

        @XmlEnumValue("relatedFrom")

        relatedFrom,

        @XmlEnumValue("relatedTo")

        relatedTo

    }

    protected RelationshipBase(){

        super();

    }

    /**

     * Creates a relationship between 2 objects and adds it to the respective

     * relation sets of both objects.

     *

     * @param from

     * @param to

     * @param type

     * @param citation

     * @param citationMicroReference

     */

    protected RelationshipBase(FROM from, TO to, TYPE type, Reference citation, String citationMicroReference) {

        super(citation, citationMicroReference, null);

        setRelatedFrom(from);

        setRelatedTo(to);

        setType(type);

        from.addRelationship(this);

        to.addRelationship(this);

    }

    public abstract TYPE getType();

    public abstract void setType(TYPE type);

    protected abstract FROM getRelatedFrom();

    protected abstract void setRelatedFrom(FROM relatedFrom);

    protected abstract TO getRelatedTo();

    protected abstract void setRelatedTo(TO relatedTo);

    /**

     * A boolean flag that marks the relationship between two objects as doubtful

     * Please be aware that this flag should not be used to mark any status of the

     * objects themselves. E.g. when marking a synonym relationship as doubtful

     * this means that it is doubtful that the synonym is really a synonym to the

     * taxon. It does not mean that the synonym is doubtfully a synonym.

     * @return true, if the relationship is doubtful, false otherwise

     */

    public boolean isDoubtful(){

        return this.doubtful;

    }

    public void setDoubtful(boolean doubtful){

        this.doubtful = doubtful;

    }

    public boolean isRemoved(){

        if ( this.getRelatedFrom() == null ^ this.getRelatedTo() == null){

            throw new IllegalStateException("A relationship may have only both related object as null or none. But just one is null!");

        }

        return this.getRelatedFrom() == null || this.getRelatedTo() == null;

    }

    public Set getDeletedObjects(){

        return this.deletedObjects;

    }

// TODO

//	UUID toUuid;

//	UUID fromUuid;

//

//	@Transient

//	public UUID getToUuidCache(){

//		return relationTo.getUuid();

//	}

//	protected void setToUuid(UUID uuid){

//		toUuid = uuid;

//	}

//

//	public UUID getFromUuid(){

//		return relationTo.getUuid();

//	}

//	protected void setFromUuid(UUID uuid){

//		fromUuid = uuid;

//	}

//*********************** CLONE ********************************************************/

    /**

     * Clones <i>this</i> relationship. This is a shortcut that enables to create

     * a new instance that differs only slightly from <i>this</i> relationship by

     * modifying only some of the attributes.

     * @throws CloneNotSupportedException

     *

     * @see eu.etaxonomy.cdm.model.common.RelationshipBase#clone()

     * @see java.lang.Object#clone()

     */

    @Override

    public Object clone() throws CloneNotSupportedException {

        RelationshipBase<FROM,TO,TYPE> result = (RelationshipBase<FROM,TO,TYPE>)super.clone();

        //no changes to: doubtful, deletedObjects

        return result;

    }

}