PathStringSearchPredicateCreator.java

package fi.codecrew.moya.facade.callbacks;

import java.util.Collections;
import java.util.List;

import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Path;
import javax.persistence.criteria.Predicate;
import javax.persistence.metamodel.SingularAttribute;

import fi.codecrew.moya.utilities.jpa.FacadeCallback;
import fi.codecrew.moya.utilities.jpa.ModelInterface;

public abstract class PathStringSearchPredicateCreator<T extends ModelInterface, D extends ModelInterface> implements FacadeCallback<T> {
	private static final String WILDCARD = "%";
	private String searchstr = null;
	private List<SingularAttribute<D, String>> attributes = null;

	public PathStringSearchPredicateCreator(String search, List<SingularAttribute<D, String>> attrs) {
		if (addSearch(search)) {
			attributes = attrs;
		}
	}

	public PathStringSearchPredicateCreator(String search, SingularAttribute<D, String> from) {
		if (addSearch(search)) {
			attributes = Collections.singletonList(from);
		}
	}

	private boolean addSearch(String search) {

		if (search != null) {
			search = search.trim().toLowerCase();
			if (!search.isEmpty()) {
				searchstr = new StringBuilder().append(WILDCARD).append(search).append(WILDCARD).toString();
				return true;
			}
		}
		searchstr = null;
		return false;
	}

	@Override
	public void exec(CriteriaBuilder cb, CriteriaQuery<?> cq, Path<T> path, List<Predicate> predicates) {
		if (searchstr == null || attributes == null || attributes.isEmpty()) {
			return;
		}
		Path<D> entityPath = getPath(path);

		for (String splitSearch : searchstr.split(" "))
		{
			splitSearch = splitSearch.trim();
			if (splitSearch.isEmpty())
				continue;
			splitSearch = new StringBuilder().append(WILDCARD).append(splitSearch).append(WILDCARD).toString();
			Predicate[] preds = new Predicate[attributes.size()];

			int i = 0;
			for (SingularAttribute<D, String> attr : attributes) {
				preds[i++] = cb.like(cb.lower(entityPath.get(attr)), splitSearch);
			}
			predicates.add(cb.or(preds));
		}
	}

	protected abstract Path<D> getPath(Path<T> root);
}