EDIT

package eu.etaxonomy.cdm.api.service;

import java.util.ArrayList;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Service;

import org.springframework.transaction.annotation.Propagation;

import org.springframework.transaction.annotation.Transactional;

import eu.etaxonomy.cdm.api.service.pager.Pager;

import eu.etaxonomy.cdm.api.service.pager.impl.AbstractPagerImpl;

import eu.etaxonomy.cdm.api.service.pager.impl.DefaultPagerImpl;

import eu.etaxonomy.cdm.model.description.IIdentificationKey;

import eu.etaxonomy.cdm.model.taxon.TaxonBase;

import eu.etaxonomy.cdm.persistence.dao.description.IIdentificationKeyDao;

@Service

@Transactional(readOnly = true, propagation = Propagation.SUPPORTS)

public class IdentificationKeyServiceImpl implements IIdentificationKeyService {

	IIdentificationKeyDao dao;

	@Autowired

	public void setDao(IIdentificationKeyDao dao) {

		this.dao = dao;

	}

	public Pager<IIdentificationKey> page(Integer pageSize, Integer pageNumber,	List<String> propertyPaths) {

		Integer numberOfResults = dao.count();

		List<IIdentificationKey> results = new ArrayList<IIdentificationKey>();

		pageNumber = pageNumber == null ? 0 : pageNumber;

		if(numberOfResults > 0) { // no point checking again //TODO use AbstractPagerImpl.hasResultsInRange(numberOfResults, pageNumber, pageSize)

			Integer start = pageSize == null ? 0 : pageSize * pageNumber;

			results = dao.list(pageSize, start, propertyPaths);

		}

		return new DefaultPagerImpl<IIdentificationKey>(pageNumber, numberOfResults, pageSize, results);

	}

	public <T extends IIdentificationKey> Pager<T> findKeysConvering(TaxonBase taxon,

			Class<T> type, Integer pageSize,

			Integer pageNumber, List<String> propertyPaths) {

		Integer numberOfResults = dao.countByTaxonomicScope(taxon, type).intValue();

		List<T> results = new ArrayList<T>();

		if(AbstractPagerImpl.hasResultsInRange(numberOfResults, pageNumber, pageSize)){

			results = dao.findByTaxonomicScope(taxon, type, pageSize, pageNumber, propertyPaths);

		}

		return new DefaultPagerImpl<T>(pageNumber, numberOfResults, pageSize, results);

	}

}