Java tutorial
/** * Copyright (c) 2014 All Rights Reserved by the SDL Group. * * 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 com.sdl.odata.unmarshaller.json; import com.fasterxml.jackson.core.JsonFactory; import com.fasterxml.jackson.core.JsonParser; import com.fasterxml.jackson.core.JsonToken; import com.sdl.odata.JsonConstants; import com.sdl.odata.api.ODataSystemException; import com.sdl.odata.api.service.MediaType; import com.sdl.odata.api.service.ODataRequestContext; import com.sdl.odata.api.unmarshaller.ODataUnmarshallingException; import com.sdl.odata.unmarshaller.AbstractLinkUnmarshaller; import org.springframework.stereotype.Component; import java.io.IOException; import java.io.UnsupportedEncodingException; import java.nio.charset.StandardCharsets; import static com.sdl.odata.util.ReferenceUtil.isNullOrEmpty; /** * Unmarshaller for POST and PUT requests where the URI is reference (it ends in ".../$ref"). The body of such a * request is expected to contain an entity reference in JSON format. This unmarshaller returns an ODataLink object * containing information about the link to be created. * <p> * See OData v4 specification part 1, paragraph 11.4.6 Modifying Relationships between Entities * See OData v4 JSON format specification, chapter 13 Entity Reference */ @Component public class JsonLinkUnmarshaller extends AbstractLinkUnmarshaller { private static final MediaType[] SUPPORTED_MEDIA_TYPES = { MediaType.JSON }; @Override protected MediaType[] supportedMediaTypes() { return SUPPORTED_MEDIA_TYPES; } @Override protected String getToEntityId(ODataRequestContext requestContext) throws ODataUnmarshallingException { // The body is expected to contain a single entity reference // See OData JSON specification chapter 13 String bodyText; try { bodyText = requestContext.getRequest().getBodyText(StandardCharsets.UTF_8.name()); } catch (UnsupportedEncodingException e) { throw new ODataSystemException("UTF-8 is not supported", e); } String idValue = null; try { JsonParser parser = new JsonFactory().createParser(bodyText); while (idValue == null && !parser.isClosed()) { JsonToken token = parser.nextToken(); if (token == null) { break; } if (token.equals(JsonToken.FIELD_NAME) && parser.getCurrentName().equals(JsonConstants.ID)) { token = parser.nextToken(); if (token.equals(JsonToken.VALUE_STRING)) { idValue = parser.getText(); } } } } catch (IOException e) { throw new ODataUnmarshallingException("Error while parsing JSON data", e); } if (isNullOrEmpty(idValue)) { throw new ODataUnmarshallingException("The JSON object in the body has no '@odata.id' value," + " or the value is empty. The JSON object in the body must have an '@odata.id' value" + " that refers to the entity to link to."); } return idValue; } }