org.apache.streams.json.JsonPathFilter.java Source code

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Here is the source code for org.apache.streams.json.JsonPathFilter.java

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/*
 * 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.streams.json;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ArrayNode;
import com.fasterxml.jackson.databind.node.ObjectNode;
import com.fasterxml.jackson.datatype.jsonorg.JsonOrgModule;
import com.google.common.base.Preconditions;
import com.google.common.collect.Lists;
import com.jayway.jsonpath.JsonPath;
import net.minidev.json.JSONArray;
import net.minidev.json.JSONObject;
import org.apache.commons.lang3.StringUtils;
import org.apache.streams.core.StreamsDatum;
import org.apache.streams.core.StreamsProcessor;
import org.apache.streams.jackson.StreamsJacksonMapper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.util.List;
import java.util.Map;

/**
 * Provides a base implementation for filtering datums which
 * do not contain specific fields using JsonPath syntax
 */
public class JsonPathFilter implements StreamsProcessor {

    private final static String STREAMS_ID = "JsonPathFilter";

    private final static Logger LOGGER = LoggerFactory.getLogger(JsonPathFilter.class);

    private ObjectMapper mapper = StreamsJacksonMapper.getInstance();

    private String pathExpression;
    private JsonPath jsonPath;
    private String destNodeName;

    public JsonPathFilter() {
        LOGGER.info("creating JsonPathFilter");
    }

    public JsonPathFilter(String pathExpression) {
        this.pathExpression = pathExpression;
        LOGGER.info("creating JsonPathFilter for " + this.pathExpression);
    }

    @Override
    public List<StreamsDatum> process(StreamsDatum entry) {

        List<StreamsDatum> result = Lists.newArrayList();

        String json = null;

        ObjectNode document = null;

        LOGGER.debug("{} processing {}", STREAMS_ID);

        if (entry.getDocument() instanceof ObjectNode) {
            document = (ObjectNode) entry.getDocument();
            try {
                json = mapper.writeValueAsString(document);
            } catch (JsonProcessingException e) {
                e.printStackTrace();
            }
        } else if (entry.getDocument() instanceof String) {
            json = (String) entry.getDocument();
            try {
                document = mapper.readValue(json, ObjectNode.class);
            } catch (IOException e) {
                e.printStackTrace();
                return null;
            }
        }

        Preconditions.checkNotNull(document);

        if (StringUtils.isNotEmpty(json)) {

            Object srcResult = null;
            try {
                srcResult = jsonPath.read(json);

            } catch (Exception e) {
                e.printStackTrace();
                LOGGER.warn(e.getMessage());
            }

            Preconditions.checkNotNull(srcResult);

            String[] path = StringUtils.split(pathExpression, '.');
            ObjectNode node = document;
            for (int i = 1; i < path.length - 1; i++) {
                node = (ObjectNode) document.get(path[i]);
            }

            Preconditions.checkNotNull(node);

            if (srcResult instanceof JSONArray) {
                try {
                    ArrayNode jsonNode = mapper.convertValue(srcResult, ArrayNode.class);
                    if (jsonNode.size() == 1) {
                        JsonNode item = jsonNode.get(0);
                        node.set(destNodeName, item);
                    } else {
                        node.set(destNodeName, jsonNode);
                    }
                } catch (Exception e) {
                    LOGGER.warn(e.getMessage());
                }
            } else if (srcResult instanceof JSONObject) {
                try {
                    ObjectNode jsonNode = mapper.convertValue(srcResult, ObjectNode.class);
                    node.set(destNodeName, jsonNode);
                } catch (Exception e) {
                    LOGGER.warn(e.getMessage());
                }
            } else if (srcResult instanceof String) {
                try {
                    node.put(destNodeName, (String) srcResult);
                } catch (Exception e) {
                    LOGGER.warn(e.getMessage());
                }
            }

        }

        result.add(new StreamsDatum(document));

        return result;

    }

    @Override
    public void prepare(Object configurationObject) {
        if (configurationObject instanceof Map) {
            Map<String, String> params = (Map<String, String>) configurationObject;
            pathExpression = params.get("pathExpression");
            jsonPath = JsonPath.compile(pathExpression);
            destNodeName = pathExpression.substring(pathExpression.lastIndexOf(".") + 1);
        }

        mapper.registerModule(new JsonOrgModule());
    }

    @Override
    public void cleanUp() {
        LOGGER.info("shutting down JsonPathFilter for " + this.pathExpression);
    }
};