org.wikidata.wdtk.datamodel.json.jackson.AliasesDeserializer.java Source code

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Here is the source code for org.wikidata.wdtk.datamodel.json.jackson.AliasesDeserializer.java

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package org.wikidata.wdtk.datamodel.json.jackson;

/*
 * #%L
 * Wikidata Toolkit Data Model
 * %%
 * Copyright (C) 2014 Wikidata Toolkit Developers
 * %%
 * 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.
 * #L%
 */

import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.JsonDeserializer;
import com.fasterxml.jackson.databind.JsonNode;

/**
 * A deserializer implementation for the aliases in an
 * {@link JacksonTermedStatementDocument}.
 * <p>
 * It implements a workaround to cope with empty aliases being represented as
 * <code>"aliases":[]</code> despite its declaration as map and not as list or
 * array. This is neither nice nor fast, and should be obsolete as soon as
 * possible.
 *
 * @see JacksonTermedStatementDocument#setAliases(Map)
 *
 * @author Fredo Erxleben
 *
 */
public class AliasesDeserializer extends JsonDeserializer<Map<String, List<JacksonMonolingualTextValue>>> {

    @Override
    public Map<String, List<JacksonMonolingualTextValue>> deserialize(JsonParser jp, DeserializationContext ctxt)
            throws IOException, JsonProcessingException {

        Map<String, List<JacksonMonolingualTextValue>> contents = new HashMap<>();

        try {
            JsonNode node = jp.getCodec().readTree(jp);
            if (!node.isArray()) {
                Iterator<Entry<String, JsonNode>> nodeIterator = node.fields();
                while (nodeIterator.hasNext()) {
                    List<JacksonMonolingualTextValue> mltvList = new ArrayList<>();
                    Entry<String, JsonNode> currentNode = nodeIterator.next();
                    // get the list of MLTVs
                    Iterator<JsonNode> mltvListIterator = currentNode.getValue().iterator();
                    while (mltvListIterator.hasNext()) {
                        JsonNode mltvEntry = mltvListIterator.next();
                        String language = mltvEntry.get("language").asText();
                        String value = mltvEntry.get("value").asText();
                        mltvList.add(new JacksonMonolingualTextValue(language, value));
                    }

                    contents.put(currentNode.getKey(), mltvList);
                }
            }

        } catch (JsonProcessingException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }

        return contents;

    }

}