/*
* Copyright 2013-2014 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.data.web;
import static org.springframework.hateoas.TemplateVariable.VariableType.*;
import org.springframework.core.MethodParameter;
import org.springframework.data.domain.Sort;
import org.springframework.hateoas.TemplateVariable;
import org.springframework.hateoas.TemplateVariable.VariableType;
import org.springframework.hateoas.TemplateVariables;
import org.springframework.hateoas.mvc.UriComponentsContributor;
import org.springframework.util.MultiValueMap;
import org.springframework.web.util.UriComponents;
import org.springframework.web.util.UriComponentsBuilder;
/**
* Extension of {@link SortHandlerMethodArgumentResolver} that also supports enhancing URIs using Spring HATEOAS
* support.
*
* @since 1.6
* @author Oliver Gierke
* @author Thomas Darimont
* @author Nick Williams
*/
public class HateoasSortHandlerMethodArgumentResolver extends SortHandlerMethodArgumentResolver implements
UriComponentsContributor {
/**
* Returns the tempalte variables for the sort parameter.
*
* @param parameter must not be {@literal null}.
* @return
* @since 1.7
*/
public TemplateVariables getSortTemplateVariables(MethodParameter parameter, UriComponents template) {
String sortParameter = getSortParameter(parameter);
MultiValueMap<String, String> queryParameters = template.getQueryParams();
boolean append = !queryParameters.isEmpty();
if (queryParameters.containsKey(sortParameter)) {
return TemplateVariables.NONE;
}
String description = String.format("pagination.%s.description", sortParameter);
VariableType type = append ? REQUEST_PARAM_CONTINUED : REQUEST_PARAM;
return new TemplateVariables(new TemplateVariable(sortParameter, type, description));
}
/*
* (non-Javadoc)
* @see org.springframework.hateoas.mvc.UriComponentsContributor#enhance(org.springframework.web.util.UriComponentsBuilder, org.springframework.core.MethodParameter, java.lang.Object)
*/
@Override
public void enhance(UriComponentsBuilder builder, MethodParameter parameter, Object value) {
if (!(value instanceof Sort)) {
return;
}
Sort sort = (Sort) value;
String sortParameter = getSortParameter(parameter);
builder.replaceQueryParam(sortParameter);
for (String expression : foldIntoExpressions(sort)) {
builder.queryParam(sortParameter, expression);
}
}
}