/*
 * Copyright 2016-2018 shardingsphere.io.
 * <p>
 * Licensed 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.
 * </p>
 */

package io.shardingsphere.core.parsing.antlr.extractor.statement.handler;

import org.antlr.v4.runtime.ParserRuleContext;

import com.google.common.base.Optional;

import io.shardingsphere.core.parsing.antlr.extractor.statement.handler.result.DropPrimaryKeyExtractResult;
import io.shardingsphere.core.parsing.antlr.extractor.statement.handler.result.ExtractResult;
import io.shardingsphere.core.parsing.antlr.extractor.statement.util.ASTUtils;

/**
 * Drop primary key extract handler.
 *
 * @author duhongjun
 */
public final class DropPrimaryKeyExtractHandler implements ASTExtractHandler {

    @Override
    public ExtractResult extract(final ParserRuleContext ancestorNode) {
        Optional<ParserRuleContext> dropPrimaryKeyNode = ASTUtils.findFirstChildNode(ancestorNode, RuleName.DROP_PRIMARY_KEY);
        if (!dropPrimaryKeyNode.isPresent()) {
            return null;
        }
        return new DropPrimaryKeyExtractResult(true);
    }
}

@@ -1207,16 +1207,20 @@
 ndler %7B%0A
+    
 %0A    @Ov
@@ -1237,16 +1237,25 @@
  public 
+Optional%3C
 ExtractR
@@ -1259,16 +1259,17 @@
 ctResult
+%3E
  extract
@@ -1506,12 +1506,25 @@
 urn 
-null
+Optional.absent()
 ;%0A  
@@ -1546,16 +1546,43 @@
  return 
+Optional.%3CExtractResult%3Eof(
 new Drop
@@ -1610,16 +1610,17 @@
 lt(true)
+)
 ;%0A    %7D%0A

use optional for checkstyle