flink-libraries/flink-sql-client/src/main/java/org/apache/flink/table/client/cli/SqlMultiLineParser.java

/*
 * 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.flink.table.client.cli;

import org.jline.reader.EOFError;
import org.jline.reader.ParsedLine;
import org.jline.reader.impl.DefaultParser;

import java.util.List;

/**
 * Multi-line parser for parsing an arbitrary number of SQL lines until a line ends with ';'.
 *
 * <p>Quoting and escaping are disabled for now.
 */
public class SqlMultiLineParser extends DefaultParser {

	private static final String EOF_CHARACTER = ";";
	private static final String NEW_LINE_PROMPT = ""; // results in simple '>' output

	public SqlMultiLineParser() {
		setEscapeChars(null);
		setQuoteChars(null);
	}

	@Override
	public ParsedLine parse(String line, int cursor, ParseContext context) {
		if (!line.trim().endsWith(EOF_CHARACTER) && context != ParseContext.COMPLETE) {
			throw new EOFError(
				-1,
				-1,
				"New line without EOF character.",
				NEW_LINE_PROMPT);
		}
		final ArgumentList parsedLine = (ArgumentList) super.parse(line, cursor, context);
		return new SqlArgumentList(
			parsedLine.line(),
			parsedLine.words(),
			parsedLine.wordIndex(),
			parsedLine.wordCursor(),
			parsedLine.cursor(),
			null,
			parsedLine.rawWordCursor(),
			parsedLine.rawWordLength());
	}

	private class SqlArgumentList extends DefaultParser.ArgumentList {

		public SqlArgumentList(
				String line,
				List<String> words,
				int wordIndex,
				int wordCursor,
				int cursor,
				String openingQuote,
				int rawWordCursor,
				int rawWordLength) {

			super(
				line,
				words,
				wordIndex,
				wordCursor,
				cursor,
				openingQuote,
				rawWordCursor,
				rawWordLength);
		}

		@Override
		public CharSequence escape(CharSequence candidate, boolean complete) {
			// escaping is skipped for now because it highly depends on the context in the SQL statement
			// e.g. 'INS(ERT INTO)' should not be quoted but 'SELECT * FROM T(axi Rides)' should
			return candidate;
		}
	}
}