EDIT

/**

 * 

 */

package eu.etaxonomy.cdm.model.common;

import java.util.HashSet;

import java.util.Iterator;

import java.util.List;

import java.util.NoSuchElementException;

import java.util.Set;

import java.util.SortedSet;

import java.util.TreeSet;

import javax.persistence.Entity;

import javax.persistence.Transient;

import org.apache.log4j.Logger;

/**

 * @author a.mueller

 *

 */

@Entity

public class OrderedTermVocabulary<T extends OrderedTermBase> extends TermVocabulary<T> {

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

	/**

	 * 

	 */

	public OrderedTermVocabulary() {

		super();

	}

	/**

	 * @param term

	 * @param label

	 * @param termSourceUri

	 */

	public OrderedTermVocabulary(String term, String label, String termSourceUri) {

		super(term, label, termSourceUri);

	}

	@Override

	@Transient

	protected Set<T> getNewTermSet(){

		return new TreeSet<T>();

	}

	@Transient

	public SortedSet<T> getHigherAndEqualTerms(T otb) {

		SortedSet<T> result = new TreeSet<T>();

		result.addAll( ((SortedSet<T>)terms).tailSet(otb));

		return result;

	}

	@Transient

	public SortedSet<T> getHigherTerms(T otb) {

		SortedSet<T> result = getHigherAndEqualTerms(otb);

		for (T setObject : terms){

			if (setObject.compareTo(otb) == 0){

				result.remove(setObject);

			}

		}

		return result;

	}

	@Transient

	public SortedSet<T> getLowerAndEqualTerms(T otb) {

		SortedSet<T> result = new TreeSet<T>();

		result.addAll( ((SortedSet<T>)terms).headSet(otb));

		return result;

	}

	@Transient

	public SortedSet<T> getLowerTerms(T otb) {

		SortedSet<T> result = getLowerAndEqualTerms(otb);

		for (T setObject : terms){

			if (setObject.compareTo(otb) == 0){

				result.remove(setObject);

			}

		}

		return result;

	}

	@Transient

	public SortedSet<T> getEqualTerms(T otb) {

		SortedSet<T> result = new TreeSet<T>();

		for (T setObject : terms){

			if (setObject.compareTo(otb) == 0){

				result.add(setObject);

			}

		}

		return result;

	}

	@Transient

	public T getNextHigherTerm(T otb) {

		try {

			return getHigherTerms(otb).first();

		} catch (NoSuchElementException e) {

			return null;

		}

	}

	@Transient

	public T getNextLowerTerm(T otb) {

		try {

			return getLowerTerms(otb).last();

		} catch (NoSuchElementException e) {

			return null;

		}

	}

	@Transient

	public T getLowestTerm() {

		try {

			return ((SortedSet<T>)terms).first();

		} catch (NoSuchElementException e) {

			return null;

		}

	}

	@Transient

	public T getHighestTerm() {

		try {

			return ((SortedSet<T>)terms).last();

		} catch (NoSuchElementException e) {

			return null;

		}

	}

	@Override

	public void addTerm(T term) throws WrongTermTypeException {

		SortedSet sortedTerms = ((SortedSet<T>)terms);

		int lowestOrderIndex;

		if (sortedTerms.size() == 0){

			lowestOrderIndex = 0;

		}else{

			Object first = (T)sortedTerms.first();

			lowestOrderIndex = ((T)first).orderIndex;

		}

		term.orderIndex = lowestOrderIndex + 1;

		super.addTerm(term);	

	}

	public void addTermAbove(T termToBeAdded, T lowerTerm) throws WrongTermTypeException {

		int orderInd = lowerTerm.orderIndex;

		termToBeAdded.orderIndex = orderInd;

		//increment all orderIndexes of terms below 

		Iterator<T> iterator = terms.iterator();

		while(iterator.hasNext()){

			T term = iterator.next();

			if (term.orderIndex >= orderInd){  //should always be true

				term.orderIndex++;

			}

		}

		super.addTerm(termToBeAdded);

	}

	public void addTermBelow(T termToBeAdded, T higherTerm) throws WrongTermTypeException {

		int orderInd = higherTerm.orderIndex;

		termToBeAdded.orderIndex = orderInd + 1;

		//increment all orderIndexes of terms below 

		Iterator<T> iterator = getLowerTerms(higherTerm).iterator();

		while(iterator.hasNext()){

			T term = iterator.next();

			if (term.orderIndex > orderInd){

				term.orderIndex++;

			}

		}

		super.addTerm(termToBeAdded);

	}

//	public void addTermEqualLevel(T termToBeAdded, T equalLevelTerm) throws WrongTermTypeException {

//		int orderInd = equalLevelTerm.orderIndex;

//		termToBeAdded.orderIndex = orderInd;

//		super.addTerm(termToBeAdded);

//	}

	@Override

	public void removeTerm(T term) {

		if (term == null){

			return;

		}

		if (this.getEqualTerms(term).size() == 0){

			Iterator<T> iterator = getLowerTerms(term).iterator();

			while (iterator.hasNext()){

				T otb = iterator.next(); 

				toBeChangedByObject = otb;

				otb.decreaseIndex(this);

				toBeChangedByObject = null;

			}

		}

		term.setVocabulary(null);

	}

	private T toBeChangedByObject;

	public boolean indexChangeAllowed(T otb){

		return otb == toBeChangedByObject ;

	}

}