LongIdGenericEntityConverter.java

package fr.openwide.core.wicket.more.util.convert.converters;

import java.util.Locale;

import org.apache.wicket.injection.Injector;
import org.apache.wicket.spring.injection.annot.SpringBean;
import org.apache.wicket.util.convert.converter.AbstractConverter;

import fr.openwide.core.jpa.business.generic.model.GenericEntity;
import fr.openwide.core.jpa.business.generic.service.IEntityService;
import fr.openwide.core.spring.util.StringUtils;

public class LongIdGenericEntityConverter<E extends GenericEntity<Long, ?>> extends AbstractConverter<E> {
	
	private static final long serialVersionUID = -6119059653808653326L;

	private final Class<E> targetType;
	
	@SpringBean
	private IEntityService entityService;

	public LongIdGenericEntityConverter(Class<E> targetType) {
		this.targetType = targetType;
	}
	
	@Override
	public String convertToString(E value, Locale locale) {
		if (value == null) {
			return null;
		}
		return convertToString(value.getId());
	}

	@Override
	public E convertToObject(String value, Locale locale) {
		if (!StringUtils.hasText(value)) {
			return null;
		}
		if (entityService == null) { // Late initialization, so that we can use this class for static variables
			Injector.get().inject(this);
		}
		return entityService.getEntity(targetType, convertToId(value, locale)); // NOSONAR findbugs:NP_NULL_ON_SOME_PATH
		// false positive NP_NULL_ON_SOME_PATH as findbugs can't see that Injector.get().inject(this) solves
		// entityService null value (NOTA : special path used when converter is a constant so that service binding
		// cannot be done at construction time.
	}
	
	private String convertToString(Long value) {
		if (value == null) {
			return null;
		}
		return String.valueOf(value);
	}
	
	private Long convertToId(String value, Locale locale) {
		try {
			return Long.valueOf(value);
		} catch (NumberFormatException e) {
			throw newConversionException(e.getMessage(), value, locale); // NOSONAR : the Wicket API forces us to lose stacktrace
		}
	}

	@Override
	protected Class<E> getTargetType() {
		return targetType;
	}

}