org.apache.olingo.commons.core.serialization.JsonEntitySetDeserializer.java Source code

Introduction

Here is the source code for org.apache.olingo.commons.core.serialization.JsonEntitySetDeserializer.java

Source

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you 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.apache.olingo.commons.core.serialization;

import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.node.ObjectNode;
import org.apache.commons.lang3.StringUtils;
import org.apache.olingo.commons.api.Constants;
import org.apache.olingo.commons.api.data.Annotation;
import org.apache.olingo.commons.api.data.EntitySet;
import org.apache.olingo.commons.api.data.ResWrap;
import org.apache.olingo.commons.api.edm.EdmPrimitiveTypeException;
import org.apache.olingo.commons.api.edm.constants.ODataServiceVersion;
import org.apache.olingo.commons.core.data.AnnotationImpl;
import org.apache.olingo.commons.core.data.EntitySetImpl;

import java.io.IOException;
import java.net.URI;
import java.util.Iterator;
import java.util.Map;

/**
 * Reads JSON string into an entity set.
 * <br/>
 * If metadata information is available, the corresponding entity fields and content will be populated.
 */
public class JsonEntitySetDeserializer extends JsonDeserializer {

    public JsonEntitySetDeserializer(final ODataServiceVersion version, final boolean serverMode) {
        super(version, serverMode);
    }

    protected ResWrap<EntitySet> doDeserialize(final JsonParser parser) throws IOException {

        final ObjectNode tree = (ObjectNode) parser.getCodec().readTree(parser);

        if (!tree.has(Constants.VALUE)) {
            return null;
        }

        final EntitySetImpl entitySet = new EntitySetImpl();

        URI contextURL;
        if (tree.hasNonNull(Constants.JSON_CONTEXT)) {
            contextURL = URI.create(tree.get(Constants.JSON_CONTEXT).textValue());
            tree.remove(Constants.JSON_CONTEXT);
        } else if (tree.hasNonNull(Constants.JSON_METADATA)) {
            contextURL = URI.create(tree.get(Constants.JSON_METADATA).textValue());
            tree.remove(Constants.JSON_METADATA);
        } else {
            contextURL = null;
        }
        if (contextURL != null) {
            entitySet.setBaseURI(StringUtils.substringBefore(contextURL.toASCIIString(), Constants.METADATA));
        }

        final String metadataETag;
        if (tree.hasNonNull(Constants.JSON_METADATA_ETAG)) {
            metadataETag = tree.get(Constants.JSON_METADATA_ETAG).textValue();
            tree.remove(Constants.JSON_METADATA_ETAG);
        } else {
            metadataETag = null;
        }

        if (tree.hasNonNull(jsonCount)) {
            entitySet.setCount(tree.get(jsonCount).asInt());
            tree.remove(jsonCount);
        }
        if (tree.hasNonNull(jsonNextLink)) {
            entitySet.setNext(URI.create(tree.get(jsonNextLink).textValue()));
            tree.remove(jsonNextLink);
        }
        if (tree.hasNonNull(jsonDeltaLink)) {
            entitySet.setDeltaLink(URI.create(tree.get(jsonDeltaLink).textValue()));
            tree.remove(jsonDeltaLink);
        }

        if (tree.hasNonNull(Constants.VALUE)) {
            final JsonEntityDeserializer entityDeserializer = new JsonEntityDeserializer(version, serverMode);
            for (JsonNode jsonNode : tree.get(Constants.VALUE)) {
                entitySet.getEntities()
                        .add(entityDeserializer.doDeserialize(jsonNode.traverse(parser.getCodec())).getPayload());
            }
            tree.remove(Constants.VALUE);
        }

        // any remaining entry is supposed to be an annotation or is ignored
        for (final Iterator<Map.Entry<String, JsonNode>> itor = tree.fields(); itor.hasNext();) {
            final Map.Entry<String, JsonNode> field = itor.next();
            if (field.getKey().charAt(0) == '@') {
                final Annotation annotation = new AnnotationImpl();
                annotation.setTerm(field.getKey().substring(1));

                try {
                    value(annotation, field.getValue(), parser.getCodec());
                } catch (final EdmPrimitiveTypeException e) {
                    throw new IOException(e);
                }
                entitySet.getAnnotations().add(annotation);
            }
        }

        return new ResWrap<EntitySet>(contextURL, metadataETag, entitySet);
    }
}