org.gradoop.flink.io.impl.json.functions.JSONToEntity.java Source code

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Here is the source code for org.gradoop.flink.io.impl.json.functions.JSONToEntity.java

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/**
 * Copyright  2014 - 2018 Leipzig University (Database Research 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 org.gradoop.flink.io.impl.json.functions;

import com.google.common.collect.Maps;
import org.codehaus.jettison.json.JSONArray;
import org.codehaus.jettison.json.JSONException;
import org.codehaus.jettison.json.JSONObject;
import org.gradoop.flink.io.impl.json.JSONConstants;
import org.gradoop.common.model.impl.id.GradoopId;
import org.gradoop.common.model.impl.id.GradoopIdSet;

import java.util.Iterator;
import java.util.Map;

/**
 * Contains methods used by all entity readers (e.g. read label, properties).
 */
public class JSONToEntity {

    /**
     * Reads the entity identifier from the json object.
     *
     * @param object json object
     * @return entity identifier
     * @throws JSONException
     */
    protected GradoopId getID(JSONObject object) throws JSONException {
        return GradoopId.fromString(object.getString(JSONConstants.IDENTIFIER));
    }

    /**
     * Reads the entity label from the json object.
     *
     * @param object json object
     * @return entity label
     * @throws JSONException
     */
    protected String getLabel(JSONObject object) throws JSONException {
        return object.getJSONObject(JSONConstants.META).getString(JSONConstants.LABEL);
    }

    /**
     * Reads the key-value properties from the json object.
     *
     * @param object json object
     * @return key-value properties
     * @throws JSONException
     */
    protected Map<String, Object> getProperties(JSONObject object) throws JSONException {
        Map<String, Object> props = Maps.newHashMapWithExpectedSize(object.length() * 2);
        object = object.getJSONObject(JSONConstants.DATA);
        Iterator<?> keys = object.keys();
        while (keys.hasNext()) {
            String key = keys.next().toString();
            Object o = object.get(key);
            props.put(key, o);
        }
        return props;
    }

    /**
     * Reads a set of graph identifiers from the json object.
     *
     * @param object json object
     * @return graph identifiers
     * @throws JSONException
     */
    protected GradoopIdSet getGraphs(JSONObject object) throws JSONException {
        GradoopIdSet result;
        if (!object.getJSONObject(JSONConstants.META).has(JSONConstants.GRAPHS)) {
            result = new GradoopIdSet();
        } else {
            result = getArrayValues(object.getJSONObject(JSONConstants.META).getJSONArray(JSONConstants.GRAPHS));
        }
        return result;
    }

    /**
     * Reads a set of Long values from a given json array.
     *
     * @param array json array
     * @return long values
     * @throws JSONException
     */
    protected GradoopIdSet getArrayValues(JSONArray array) throws JSONException {

        GradoopIdSet result = new GradoopIdSet();

        for (int i = 0; i < array.length(); i++) {
            result.add(GradoopId.fromString(array.getString(i)));
        }
        return result;
    }
}