/*
 * 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.executor.sql.execute.result;

import com.google.common.collect.HashMultimap;
import com.google.common.collect.Multimap;
import io.shardingsphere.core.merger.QueryResult;

import java.io.InputStream;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Collection;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map.Entry;

/**
 * Query result for memory loading.
 *
 * @author zhangliang
 * @author panjuan
 */
public final class DistinctQueryResult implements QueryResult {
    
    private final Multimap<String, Integer> columnLabelAndIndexMap;
    
    private final Iterator<List<Object>> resultData;
    
    private List<Object> currentRow;
    
    public DistinctQueryResult(final ResultSet resultSet) throws SQLException {
        columnLabelAndIndexMap = getMetaData(resultSet.getMetaData());
        resultData = getResultData(resultSet);
    }
    
    private Multimap<String, Integer> getMetaData(final ResultSetMetaData resultSetMetaData) throws SQLException {
        Multimap<String, Integer> result = HashMultimap.create();
        for (int columnIndex = 1; columnIndex <= resultSetMetaData.getColumnCount(); columnIndex++) {
            result.put(resultSetMetaData.getColumnLabel(columnIndex), columnIndex);
        }
        return result;
    }
    
    private Iterator<List<Object>> getResultData(final ResultSet resultSet) throws SQLException {
        Collection<List<Object>> result = new LinkedList<>();
        while (resultSet.next()) {
            List<Object> row = new ArrayList<>(columnLabelAndIndexMap.size());
            for (int columnIndex = 1; columnIndex <= resultSet.getMetaData().getColumnCount(); columnIndex++) {
                row.add(resultSet.getObject(columnIndex));
            }
            result.add(row);
        }
        return result.iterator();
    }
    
    @Override
    public boolean next() {
        if (resultData.hasNext()) {
            currentRow = resultData.next();
            return true;
        }
        currentRow = null;
        return false;
    }
    
    @Override
    public Object getValue(final int columnIndex, final Class<?> type) {
        return currentRow.get(columnIndex - 1);
    }
    
    @Override
    public Object getValue(final String columnLabel, final Class<?> type) {
        return currentRow.get(getIndexByColumnLabel(columnLabel));
    }
    
    @Override
    public Object getCalendarValue(final int columnIndex, final Class<?> type, final Calendar calendar) {
        return currentRow.get(columnIndex - 1);
    }
    
    @Override
    public Object getCalendarValue(final String columnLabel, final Class<?> type, final Calendar calendar) {
        return currentRow.get(getIndexByColumnLabel(columnLabel));
    }
    
    @Override
    public InputStream getInputStream(final int columnIndex, final String type) {
        return (InputStream) currentRow.get(columnIndex - 1);
    }
    
    @Override
    public InputStream getInputStream(final String columnLabel, final String type) {
        return (InputStream) currentRow.get(getIndexByColumnLabel(columnLabel));
    }
    
    @Override
    public boolean wasNull() {
        return null == currentRow;
    }
    
    @Override
    public int getColumnCount() {
        return columnLabelAndIndexMap.size();
    }
    
    @Override
    public String getColumnLabel(final int columnIndex) throws SQLException {
        for (Entry<String, Integer> entry : columnLabelAndIndexMap.entries()) {
            if (columnIndex == entry.getValue()) {
                return entry.getKey();
            }
        }
        throw new SQLException("Column index out of range", "9999");
    }
    
    private Integer getIndexByColumnLabel(final String columnLabel) {
        return new ArrayList<>(columnLabelAndIndexMap.get(columnLabel)).get(0) - 1;
    }
}

@@ -1134,17 +1134,26 @@
 %0A/**%0A * 
-Q
+Distinct q
 uery res
@@ -1159,53 +1159,12 @@
 sult
- for memory loading.%0A *%0A * @author zhangliang
+.%0A *
 %0A * 
@@ -1256,1344 +1256,8 @@
    %0A
-    private final Multimap%3CString, Integer%3E columnLabelAndIndexMap;%0A    %0A    private final Iterator%3CList%3CObject%3E%3E resultData;%0A    %0A    private List%3CObject%3E currentRow;%0A    %0A    public DistinctQueryResult(final ResultSet resultSet) throws SQLException %7B%0A        columnLabelAndIndexMap = getMetaData(resultSet.getMetaData());%0A        resultData = getResultData(resultSet);%0A    %7D%0A    %0A    private Multimap%3CString, Integer%3E getMetaData(final ResultSetMetaData resultSetMetaData) throws SQLException %7B%0A        Multimap%3CString, Integer%3E result = HashMultimap.create();%0A        for (int columnIndex = 1; columnIndex %3C= resultSetMetaData.getColumnCount(); columnIndex++) %7B%0A            result.put(resultSetMetaData.getColumnLabel(columnIndex), columnIndex);%0A        %7D%0A        return result;%0A    %7D%0A    %0A    private Iterator%3CList%3CObject%3E%3E getResultData(final ResultSet resultSet) throws SQLException %7B%0A        Collection%3CList%3CObject%3E%3E result = new LinkedList%3C%3E();%0A        while (resultSet.next()) %7B%0A            List%3CObject%3E row = new ArrayList%3C%3E(columnLabelAndIndexMap.size());%0A            for (int columnIndex = 1; columnIndex %3C= resultSet.getMetaData().getColumnCount(); columnIndex++) %7B%0A                row.add(resultSet.getObject(columnIndex));%0A            %7D%0A            result.add(row);%0A        %7D%0A        return result.iterator();%0A    %7D%0A    %0A
     
@@ -3084,171 +3084,6 @@
   %7D%0A
-    %0A    private Integer getIndexByColumnLabel(final String columnLabel) %7B%0A        return new ArrayList%3C%3E(columnLabelAndIndexMap.get(columnLabel)).get(0) - 1;%0A    %7D%0A
 %7D%0A

modify java doc for DistinctQueryResult