vvysotskyi commented on a change in pull request #1971: DRILL-7572: JSON structure parser URL: https://github.com/apache/drill/pull/1971#discussion_r378182270
########## File path: exec/java-exec/src/main/java/org/apache/drill/exec/store/easy/json/parser/JsonStructureParser.java ########## @@ -0,0 +1,183 @@ +/* + * 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.drill.exec.store.easy.json.parser; + +import java.io.IOException; +import java.io.InputStream; + +import org.apache.drill.exec.store.easy.json.parser.RootParser.RootArrayParser; +import org.apache.drill.exec.store.easy.json.parser.RootParser.RootObjectParser; +import org.apache.drill.exec.store.easy.json.parser.TokenIterator.RecoverableJsonException; +import org.apache.drill.shaded.guava.com.google.common.base.Preconditions; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import com.fasterxml.jackson.core.JsonParseException; +import com.fasterxml.jackson.core.JsonParser; +import com.fasterxml.jackson.core.JsonToken; +import com.fasterxml.jackson.databind.ObjectMapper; + +public class JsonStructureParser { + protected static final Logger logger = LoggerFactory.getLogger(JsonStructureParser.class); + + final JsonParser parser; + private final JsonStructureOptions options; + private final TokenIterator tokenizer; + private final RootParser rootState; + private int errorRecoveryCount; + + public JsonStructureParser(InputStream stream, JsonStructureOptions options) { + Preconditions.checkNotNull(options); + Preconditions.checkNotNull(options.rootListener); + Preconditions.checkNotNull(options.errorFactory); + this.options = options; + try { + ObjectMapper mapper = new ObjectMapper() + .configure(JsonParser.Feature.ALLOW_COMMENTS, true) + .configure(JsonParser.Feature.ALLOW_UNQUOTED_FIELD_NAMES, true); + if (options.allowNanInf) { + mapper.configure(JsonParser.Feature.ALLOW_NON_NUMERIC_NUMBERS, true); + } + + parser = mapper.getFactory().createParser(stream); + } catch (JsonParseException e) { + throw errorFactory().parseError("Failed to create the JSON parser", e); + } catch (IOException e) { + throw errorFactory().ioException(e); + } + tokenizer = new TokenIterator(parser, options, errorFactory()); + rootState = makeRootState(); + } + + public ErrorFactory errorFactory() { return options.errorFactory; } + + public JsonStructureOptions options() { return options; } + + private RootParser makeRootState() { + JsonToken token = tokenizer.next(); + if (token == null) { + return null; + } + switch (token) { + + // File contains an array of records. + case START_ARRAY: + if (options.skipOuterList) { + return new RootArrayParser(this); + } else { + throw errorFactory().structureError( + "JSON includes an outer array, but outer array support is not enabled"); + } + + // File contains a sequence of one or more records, + // presumably sequentially. + case START_OBJECT: + tokenizer.unget(token); + return new RootObjectParser(this); + + // Not a valid JSON file for Drill. + // Won't get here because the Jackson parser catches errors. + default: + throw errorFactory().syntaxError(token); + } + } + + public boolean next() { + if (rootState == null) { + // Only occurs for an empty document + return false; + } + for (;;) { + try { + return rootState.parseRoot(tokenizer); + } catch (RecoverableJsonException e) { + if (! recover()) { + return false; + } + } + } + } + + /** + * Attempt recovery from a JSON syntax error by skipping to the next + * record. The Jackson parser is quite limited in its recovery abilities. + * + * @return {@code true{@code if another record can be read, {@code false} Review comment: Please fix the tags. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services
