[
https://issues.apache.org/jira/browse/DRILL-7572?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17035309#comment-17035309
]
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_r378190159
##########
File path:
exec/java-exec/src/main/java/org/apache/drill/exec/store/easy/json/parser/RootParser.java
##########
@@ -0,0 +1,121 @@
+/*
+ * 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 org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.fasterxml.jackson.core.JsonToken;
+
+/**
+ * The root parsers are special: they must detect EOF. Drill supports
+ * top-level objects either enclosed in an array (which forms legal
+ * JSON), or as a series JSON objects (which is a common, if not
+ * entirely legal, form of JSON.)
+ */
+public abstract class RootParser implements ElementParser {
+ protected static final Logger logger =
LoggerFactory.getLogger(RootParser.class);
+
+ private final JsonStructureParser structParser;
+ protected final ObjectParser rootObject;
+
+ public RootParser(JsonStructureParser structParser) {
+ this.structParser = structParser;
+ this.rootObject = new ObjectParser(this,
structParser.options().rootListener);
+ }
+
+ public abstract boolean parseRoot(TokenIterator tokenizer);
+
+ @Override
+ public void parse(TokenIterator tokenizer) {
+ throw new UnsupportedOperationException();
+ }
+
+ protected boolean parseRootObject(JsonToken token, TokenIterator tokenizer) {
+ // Position: ^ ?
+ switch (token) {
+ case NOT_AVAILABLE:
+ return false; // Should never occur
+
+ case START_OBJECT:
+ // Position: { ^
+ rootObject.parse(tokenizer);
+ break;
+
+ default:
+ // Position ~{ ^
+ // Not a valid object.
+ // Won't actually get here: the Jackson parser prevents it.
+ throw errorFactory().syntaxError(token); // Nothing else is valid
+ }
+ return true;
+ }
+
+ protected ErrorFactory errorFactory() {
+ return structParser.errorFactory();
+ }
+
+ @Override
+ public ElementParser parent() { return null; }
+
+ @Override
+ public JsonStructureParser structParser() { return structParser; }
+
+ public static class RootObjectParser extends RootParser {
+
+ public RootObjectParser(JsonStructureParser structParser) {
+ super(structParser);
+ }
+
+ @Override
+ public boolean parseRoot(TokenIterator tokenizer) {
+ JsonToken token = tokenizer.next();
+ if (token == null) {
+ // Position: EOF ^
+ return false;
+ } else {
+ return parseRootObject(token, tokenizer);
+ }
+ }
+ }
+
+ public static class RootArrayParser extends RootParser {
+
+ public RootArrayParser(JsonStructureParser structParser) {
+ super(structParser);
+ }
+
+ @Override
+ public boolean parseRoot(TokenIterator tokenizer) {
+ JsonToken token = tokenizer.next();
+ if (token == null) {
+ // Position: { ... EOF ^
+ // Saw EOF, but no closing ]. Warn and ignore.
+ // Note that the Jackson parser won't let us get here;
+ // it will have already thrown a syntax error.
+ logger.warn("Failed to close outer array. {}",
+ tokenizer.context());
+ return false;
+ } else if (token == JsonToken.END_ARRAY) {
+ return false;
+ } else {
+ return parseRootObject(token, tokenizer);
+ }
+ }
+ }
+}
Review comment:
Please add empty line.
----------------------------------------------------------------
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]
> 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.)
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
