/*
 * 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 java.util.Collection;

import org.antlr.v4.runtime.ParserRuleContext;

import com.google.common.base.Optional;

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

/**
 * Create table primary key extract handler.
 *
 * @author duhongjun
 */
public final class CreatePrimaryKeyExtractHandler implements ASTExtractHandler {

    @Override
    public ExtractResult extract(final ParserRuleContext ancestorNode) {
        Optional<ParserRuleContext> primaryKeyNode = ASTUtils.findFirstChildNode(ancestorNode, RuleName.PRIMARY_KEY);
        if (!primaryKeyNode.isPresent()) {
            return null;
        }
        Optional<ParserRuleContext> columnListNode = ASTUtils.findFirstChildNode(primaryKeyNode.get().getParent().getParent(), RuleName.COLUMN_LIST);
        if (!columnListNode.isPresent()) {
            return null;
        }
        Collection<ParserRuleContext> result = ASTUtils.getAllDescendantNodes(columnListNode.get(), RuleName.COLUMN_NAME);
        if (result.isEmpty()) {
            return null;
        }
        PrimaryKeyExtractResult extractResult = new PrimaryKeyExtractResult();
        for (ParserRuleContext each : result) {
            extractResult.getPrimaryKeyColumnNames().add(each.getText());
        }
        return extractResult;
    }
}

@@ -1243,16 +1243,20 @@
 ndler %7B%0A
+    
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@@ -1273,16 +1273,25 @@
  public 
+Optional%3C
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@@ -1287,32 +1287,33 @@
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@@ -1517,36 +1517,49 @@
          return 
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 ;%0A        %7D%0A    
@@ -1758,36 +1758,49 @@
          return 
-null
+Optional.absent()
 ;%0A        %7D%0A    
@@ -1833,22 +1833,31 @@
 ontext%3E 
-result
+columnNameNodes
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@@ -1939,22 +1939,31 @@
     if (
-result
+columnNameNodes
 .isEmpty
@@ -1991,12 +1991,25 @@
 urn 
-null
+Optional.absent()
 ;%0A  
@@ -2048,24 +2048,17 @@
 tResult 
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+r
 esult = 
@@ -2126,22 +2126,31 @@
  each : 
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+columnNameNodes
 ) %7B%0A    
@@ -2157,24 +2157,17 @@
         
-extractR
+r
 esult.ge
@@ -2237,17 +2237,27 @@
  return 
-e
+Optional.%3CE
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@@ -2260,16 +2260,27 @@
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+%3Eof(result)
 ;%0A    %7D%0A

use optional for checkstyle