/*
 * 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 io.shardingsphere.core.parsing.antlr.extractor.statement.util.ASTUtils;
import io.shardingsphere.core.parsing.antlr.sql.ddl.AlterTableStatement;
import io.shardingsphere.core.parsing.parser.sql.SQLStatement;
import io.shardingsphere.core.util.SQLUtil;
import org.antlr.v4.runtime.ParserRuleContext;
import org.antlr.v4.runtime.tree.ParseTree;

/**
 * Drop column extract handler.
 * 
 * @author duhongjun
 */
public final class DropColumnExtractHandler implements ASTExtractHandler {
    
    @Override
    public void extract(final ParserRuleContext ancestorNode, final SQLStatement statement) {
        AlterTableStatement alterStatement = (AlterTableStatement) statement;
        for (ParserRuleContext each : ASTUtils.getAllDescendantNodes(ancestorNode, RuleName.DROP_COLUMN)) {
            for (ParseTree columnNode : ASTUtils.getAllDescendantNodes(each, RuleName.COLUMN_NAME)) {
                alterStatement.getDropColumns().add(SQLUtil.getExactlyValue(columnNode.getText()));
            }
        }
    }
}

@@ -688,16 +688,108 @@
 ndler;%0A%0A
+import org.antlr.v4.runtime.ParserRuleContext;%0Aimport org.antlr.v4.runtime.tree.ParseTree;%0A%0A
 import i
@@ -848,21 +848,46 @@
 ent.
-util.ASTUtils
+handler.result.DropColumnExtractResult
 ;%0Aim
@@ -928,16 +928,189 @@
 g.antlr.
+extractor.statement.handler.result.ExtractResult;%0Aimport io.shardingsphere.core.parsing.antlr.extractor.statement.util.ASTUtils;%0Aimport io.shardingsphere.core.parsing.antlr.
 sql.ddl.
@@ -1239,99 +1239,8 @@
 Util
-;%0Aimport org.antlr.v4.runtime.ParserRuleContext;%0Aimport org.antlr.v4.runtime.tree.ParseTree
 ;%0A%0A/
@@ -1375,16 +1375,35 @@
 tHandler
+,ASTExtractHandler1
  %7B%0A    %0A
@@ -1927,11 +1927,545 @@
  %7D%0A    %7D
+%0A%0A    @Override%0A    public ExtractResult extract(ParserRuleContext ancestorNode) %7B%0A        DropColumnExtractResult extractResult = new DropColumnExtractResult();%0A        for (ParserRuleContext each : ASTUtils.getAllDescendantNodes(ancestorNode, RuleName.DROP_COLUMN)) %7B%0A            for (ParseTree columnNode : ASTUtils.getAllDescendantNodes(each, RuleName.COLUMN_NAME)) %7B%0A                extractResult.getDropColumnNames().add(SQLUtil.getExactlyValue(columnNode.getText()));%0A            %7D%0A        %7D%0A        return extractResult;%0A    %7D
 %0A%7D%0A

implement ASTExtractHandler1