/*
* 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 org.apache.streams.core.StreamsDatum;
import org.apache.streams.core.StreamsProcessor;
import org.apache.streams.jackson.StreamsJacksonMapper;
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.jayway.jsonpath.JsonPath;
import net.minidev.json.JSONArray;
import net.minidev.json.JSONObject;
import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Objects;
/**
* Provides a base implementation for filtering datums which
* do not contain specific fields using JsonPath syntax.
*/
public class JsonPathFilter implements StreamsProcessor {
private static final String STREAMS_ID = "JsonPathFilter";
private static final 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 String getId() {
return STREAMS_ID;
}
@Override
public List<StreamsDatum> process(StreamsDatum entry) {
List<StreamsDatum> result = new ArrayList<>();
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 ex) {
ex.printStackTrace();
}
} else if ( entry.getDocument() instanceof String ) {
json = (String) entry.getDocument();
try {
document = mapper.readValue(json, ObjectNode.class);
} catch (IOException ex) {
ex.printStackTrace();
return null;
}
}
Objects.requireNonNull(document);
if ( StringUtils.isNotEmpty(json)) {
Object srcResult = null;
try {
srcResult = jsonPath.read(json);
} catch ( Exception ex ) {
ex.printStackTrace();
LOGGER.warn(ex.getMessage());
}
Objects.requireNonNull(srcResult);
String[] path = StringUtils.split(pathExpression, '.');
ObjectNode node = document;
for (int i = 1; i < path.length - 1; i++) {
node = (ObjectNode) document.get(path[i]);
}
Objects.requireNonNull(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 ex) {
LOGGER.warn(ex.getMessage());
}
} else if ( srcResult instanceof JSONObject ) {
try {
ObjectNode jsonNode = mapper.convertValue(srcResult, ObjectNode.class);
node.set(destNodeName, jsonNode);
} catch (Exception ex) {
LOGGER.warn(ex.getMessage());
}
} else if ( srcResult instanceof String ) {
try {
node.put(destNodeName, (String) srcResult);
} catch (Exception ex) {
LOGGER.warn(ex.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);
}
}
@Override
public void cleanUp() {
LOGGER.info("shutting down JsonPathFilter for " + this.pathExpression);
}
}