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This module bridges Table/SQL API and runtime. It contains
all resources that are required during pre-flight and runtime
phase. The content of this module is work-in-progress. It will
replace flink-table-planner once it is stable. See FLINK-11439
and FLIP-32 for more details.
/*
* 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.planner.parse;
import org.apache.flink.table.operations.Operation;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Optional;
/**
* {@link ExtendedParser} is used for parsing some special command which can't supported by {@link
* CalciteParser}, e.g. {@code SET key=value} may contain special characters in key and value. It's
* also a good idea to move some parsing strategy here to avoid introducing new reserved keywords.
*/
public class ExtendedParser {
public static final ExtendedParser INSTANCE = new ExtendedParser();
private static final List PARSE_STRATEGIES =
Arrays.asList(
ClearOperationParseStrategy.INSTANCE,
HelpOperationParseStrategy.INSTANCE,
QuitOperationParseStrategy.INSTANCE,
ResetOperationParseStrategy.INSTANCE,
SetOperationParseStrategy.INSTANCE);
/**
* Parse the input statement to the {@link Operation}.
*
* @param statement the command to evaluate
* @return parsed operation that represents the command
*/
public Optional parse(String statement) {
for (ExtendedParseStrategy strategy : PARSE_STRATEGIES) {
if (strategy.match(statement)) {
return Optional.of(strategy.convert(statement));
}
}
return Optional.empty();
}
/**
* Returns completion hints for the given statement at the given cursor position. The completion
* happens case insensitively.
*
* @param statement Partial or slightly incorrect SQL statement
* @param cursor cursor position
* @return completion hints that fit at the current cursor position
*/
public String[] getCompletionHints(String statement, int cursor) {
String normalizedStatement = statement.trim().toUpperCase();
List hints = new ArrayList<>();
for (ExtendedParseStrategy strategy : PARSE_STRATEGIES) {
for (String hint : strategy.getHints()) {
if (hint.startsWith(normalizedStatement) && cursor < hint.length()) {
hints.add(getCompletionHint(normalizedStatement, hint));
}
}
}
return hints.toArray(new String[0]);
}
private String getCompletionHint(String statement, String commandHint) {
if (statement.length() == 0) {
return commandHint;
}
int cursorPos = statement.length() - 1;
int returnStartPos;
if (Character.isWhitespace(commandHint.charAt(cursorPos + 1))) {
returnStartPos = Math.min(commandHint.length() - 1, cursorPos + 2);
} else {
// 'add ja' should return 'jar'
returnStartPos = cursorPos;
while (returnStartPos > 0
&& !Character.isWhitespace(commandHint.charAt(returnStartPos - 1))) {
returnStartPos--;
}
}
return commandHint.substring(returnStartPos);
}
}