EDIT

// $Id$

/**

* 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.metadata;

import java.io.Serializable;

import javax.persistence.Column;

import javax.persistence.Embeddable;

import javax.persistence.EmbeddedId;

import javax.persistence.Entity;

import org.hibernate.validator.constraints.Length;

/**

 * This class may hold all prefrences data for a CDM database.

 * E.g. one may store what the default nomenclatural code is,

 * or which default formatter (cache strategy) to use for a 

 * certain class.

 * The structure represents a triple where the first item 

 * (subject) defines for which object the given information is valid. 

 * The second item (predicate) describes the type of information

 * and the third item (value) represents the actual value.

 * 

 *  E.g. for defining a database wide default nomenclatural code

 *  you may define a triple ("database", "eu.etaxonomy.cdm.model.name.NomenclaturalCode", "ICZN").

 *  The set of allowed values and semantics for each combination 

 *  is up to implementing classes.

 *  The only restrictions we have is the length of the fields and

 *  the fact that the first two items (subject, predicate) do

 *  create a unique key.

 *  

 *  Size of single fields may be enlarged in future versions. "Value" may

 *  become a CLOB.

 * 

 * @author a.mueller

 * @created 03.07.2013

 */

@Entity

public final class CdmPreference implements Serializable {

	private static final long serialVersionUID = 4307599154287181582L;

	public static final CdmPreference NewInstance(PreferenceSubject subject, PreferencePredicate predicate, String value){

		return new CdmPreference(subject, predicate, value);

	}

	public static PrefKey NewKey(PreferenceSubject subject, PreferencePredicate predicate){

		return new PrefKey(subject, predicate);

	}

	@Embeddable

	public static class PrefKey implements Serializable{

		private static final long serialVersionUID = 9019957853773606194L;

		@Column(name="key_subject", length=100) //for now we keep the combined key short as indizes for such keys are very limited in size in some DBMS. Size may be increased later

		private String subject;

		@Column(name="key_predicate", length=100) //for now we keep the combined key short as indizes for such keys are very limited in size in some DBMS. Size may be increased later

		private String predicate;

		//for hibernate use only

		private PrefKey(){}

		private PrefKey(PreferenceSubject subject, PreferencePredicate predicate){

			this(subject.getKey(), predicate.getKey());

		}

		private PrefKey(String subject, String predicate){

			if (subject == null) throw new IllegalArgumentException("Subject must not be null for preference");

			if (predicate == null) throw new IllegalArgumentException("Predicate must not be null for preference");

			if (subject.length() > 255) throw new IllegalArgumentException("Subject must not be longer then 255 for preference");

			if (predicate.length() > 255) throw new IllegalArgumentException("Predicate must not be longer then 255 for preference");

			this.subject = subject;

			this.predicate = predicate;

		}

		@Override

		public int hashCode() {

			final int prime = 31;

			int result = 1;

			result = prime * result + ((predicate == null) ? 0 : predicate.hashCode());

			result = prime * result	+ ((subject == null) ? 0 : subject.hashCode());

			return result;

		}

		@Override

		public boolean equals(Object obj) {

			if (this == obj){

				return true;

			} else if (obj == null){

				return false;

			}else if (getClass() != obj.getClass()){

				return false;

			}else{

				PrefKey other = (PrefKey) obj;

				return ( predicate.equals(other.predicate) && subject.equals(other.subject));

			}

		} 

	}

	@EmbeddedId

	private PrefKey key;

	@Length(max=1023)

	private String value;

//****************** CONSTRUCTOR **********************/	

	//for hibernate use only

	@SuppressWarnings("unused")

	private CdmPreference(){};

	/**

	 * Constructor.

	 * @param subject must not be null and must not be longer then 255 characters.

	 * @param predicate must not be null and must not be longer then 255 characters.

	 * @param value must not be longer then 1023 characters.

	 */

	public CdmPreference(PreferenceSubject subject, PreferencePredicate predicate, String value){

		this.key = new PrefKey(subject, predicate);

		//TODO are null values allowed?		assert predicate != null : "value must not be null for preference";

		if (value != null && value.length() > 1023) {throw new IllegalArgumentException(

				String.format("value must not be longer then 1023 characters for preference. Value = %s", value));

		}

		this.value = value;

	}

	/**

	 * Constructor.

	 * @param subject must not be null and must not be longer then 255 characters.

	 * @param predicate must not be null and must not be longer then 255 characters.

	 * @param value must not be longer then 1023 characters.

	 */

	public CdmPreference(String subject, String predicate, String value){

		this.key = new PrefKey(subject, predicate);

		//TODO are null values allowed?		assert predicate != null : "value must not be null for preference";

		if (value != null && value.length() > 1023) {throw new IllegalArgumentException(

			String.format("value must not be longer then 1023 characters for preference. Value = %s", value));

		}

		this.value = value;

	}

//************************ GETTER / SETTER ***************************/	

	public String getSubject() {

		return key.subject;

	}

	public String getPredicate() {

		return key.predicate;

	}

	public String getValue() {

		return value;

	}

	public PrefKey getKey() {

		return key;

	}

//

//	we try to avoid setting of values

//	public void setValue(String value) {

//		this.value = value;

//	}

}