/*
 * 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.dialect.oracle;

import org.antlr.v4.runtime.ParserRuleContext;

import com.google.common.base.Optional;

import io.shardingsphere.core.parsing.antlr.extractor.statement.handler.ASTExtractHandler;
import io.shardingsphere.core.parsing.antlr.extractor.statement.handler.ASTExtractHandler1;
import io.shardingsphere.core.parsing.antlr.extractor.statement.handler.RuleName;
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;
import io.shardingsphere.core.parsing.antlr.sql.ddl.AlterTableStatement;
import io.shardingsphere.core.parsing.parser.sql.SQLStatement;

/**
 * Drop primary key extract handler for Oracle.
 * 
 * @author duhongjun
 */
public final class OracleDropPrimaryKeyExtractHandler implements ASTExtractHandler,ASTExtractHandler1 {
    
    @Override
    public void extract(final ParserRuleContext rootNode, final SQLStatement statement) {
        AlterTableStatement alterStatement = (AlterTableStatement) statement;
        Optional<ParserRuleContext> dropConstraintNode = ASTUtils.findFirstChildNode(rootNode, RuleName.DROP_CONSTRAINT_CLAUSE);
        if (dropConstraintNode.isPresent()) {
            Optional<ParserRuleContext> primaryKeyNode = ASTUtils.findFirstChildNode(dropConstraintNode.get(), RuleName.PRIMARY_KEY);
            if (primaryKeyNode.isPresent()) {
                alterStatement.setDropPrimaryKey(true);
            }
        }
    }

    @Override
    public ExtractResult extract(ParserRuleContext ancestorNode) {
        DropPrimaryKeyExtractResult extractResult = new DropPrimaryKeyExtractResult();
        Optional<ParserRuleContext> dropConstraintNode = ASTUtils.findFirstChildNode(ancestorNode, RuleName.DROP_CONSTRAINT_CLAUSE);
        if (dropConstraintNode.isPresent()) {
            Optional<ParserRuleContext> primaryKeyNode = ASTUtils.findFirstChildNode(dropConstraintNode.get(), RuleName.PRIMARY_KEY);
            if (primaryKeyNode.isPresent()) {
                extractResult.setDropPrimaryKey(true);
            }
        }
        return extractResult;
    }
}

@@ -2374,95 +2374,8 @@
 ) %7B%0A
-        DropPrimaryKeyExtractResult extractResult = new DropPrimaryKeyExtractResult();%0A
     
@@ -2507,32 +2507,33 @@
 E);%0A        if (
+!
 dropConstraintNo
@@ -2546,32 +2546,63 @@
 resent()) %7B%0A    
+        return null;%0A        %7D%0A
         Optional
@@ -2719,32 +2719,29 @@
 Y);%0A        
-    
 if (
+!
 primaryKeyNo
@@ -2774,91 +2774,65 @@
     
-    extractResult.setDropPrimaryKey(true);%0A            %7D%0A        %7D%0A        return e
+return null;%0A        %7D%0A        return new DropPrimaryKeyE
 xtra
@@ -2839,16 +2839,22 @@
 ctResult
+(true)
 ;%0A    %7D%0A

extract nothing return null