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https://issues.apache.org/jira/browse/DRILL-7572?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17035308#comment-17035308
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ASF GitHub Bot commented on DRILL-7572:
---------------------------------------
vvysotskyi commented on 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.
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> JSON structure parser
> ---------------------
>
> Key: DRILL-7572
> URL: https://issues.apache.org/jira/browse/DRILL-7572
> Project: Apache Drill
> Issue Type: Improvement
> Affects Versions: 1.18.0
> Reporter: Paul Rogers
> Assignee: Paul Rogers
> Priority: Major
> Fix For: 1.18.0
>
>
> DRILL-6953, PR #1913 provides an EVF-version of the JSON reader. The original
> plan was to commit a first draft, with the feature disabled, then evolve from
> there. Review comments suggested we ensure that the first PR pass all unit
> tests with the feature enabled. Another comment suggested the JSON parser
> portion be reusable for other format or storage plugins. All good ideas.
> The amount of change in the original PR was becoming too large. So, we'll go
> ahead and split the work into smaller portions.
> This ticket is for the "JSON structure parser." This parser accepts the token
> stream from the Jackson parser and provides a framework to create a tree
> structure that describes the data. To keep the code simple, to simplify
> tests, and to make review easier, the structure parser does not directly
> integrate with the rest of Drill. Instead, it provides a number of listener
> interfaces which the next level implements. (The next level will be in
> another PR.)
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