/*******************************************************************************
* Copyright (c) 2014 Oracle. All rights reserved.
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
* which accompanies this distribution.
* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
* and the Eclipse Distribution License is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* Contributors:
* Dmitry Kornilov - initial implementation
******************************************************************************/
package org.eclipse.persistence.jpa.rs.features.paging;
import org.eclipse.persistence.jpa.rs.QueryParameters;
import org.eclipse.persistence.jpa.rs.annotations.RestPageable;
import org.eclipse.persistence.jpa.rs.exceptions.JPARSException;
import javax.ws.rs.core.UriInfo;
import java.lang.reflect.Field;
/**
* Finds out if an entity field is pageable and validates paging parameters.
*
* @author Dmitry Kornilov
*/
public final class PageableFieldValidator extends AbstractPagingValidator {
private final Class entityClass;
private final String fieldName;
/**
* Creates the validator.
*
* @param entityClass entity class containing a field to validate.
* @param fieldName field name to validate.
* @param uri request URI.
*/
public PageableFieldValidator(Class entityClass, String fieldName, UriInfo uri) {
super(uri);
this.entityClass = entityClass;
this.fieldName = fieldName;
}
/**
* Checks if request is valid.
*
* @return true if request is valid and supports pagination, false if request is valid but doesn't support pagination.
* @throws org.eclipse.persistence.jpa.rs.exceptions.JPARSException in case of any validation errors.
*/
@Override
public boolean isFeatureApplicable() throws JPARSException {
final RestPageable paginationData = getPaginationData();
if (paginationData != null) {
// Field supports pagination, do parameters check
checkParameters(paginationData.limit());
return true;
} else {
// Pagination is not supported by query. Check that there are no pagination related query parameters.
if (queryParameters.containsKey(QueryParameters.JPARS_PAGING_LIMIT)
|| queryParameters.containsKey(QueryParameters.JPARS_PAGING_OFFSET)) {
throw JPARSException.paginationParameterForNotPageableResource();
}
return false;
}
}
/**
* Returns {@link RestPageable} annotation of entityClass.fieldName field or null if it doesn't exist.
*
* @return RestPageable or null if it doesn't exist.
*/
private RestPageable getPaginationData() {
try {
final Field fld = entityClass.getDeclaredField(fieldName);
if (fld.isAnnotationPresent(RestPageable.class)) {
return fld.getAnnotation(RestPageable.class);
}
return null;
} catch (NoSuchFieldException e) {
return null;
}
}
}