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io.shardingsphere.core.rewrite.SQLRewriteEngine Maven / Gradle / Ivy
/*
* Copyright 2016-2018 shardingsphere.io.
*
* 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.
*
*/
package io.shardingsphere.core.rewrite;
import com.google.common.base.Optional;
import com.google.common.base.Strings;
import io.shardingsphere.core.constant.DatabaseType;
import io.shardingsphere.core.optimizer.condition.ShardingConditions;
import io.shardingsphere.core.parsing.lexer.token.DefaultKeyword;
import io.shardingsphere.core.parsing.parser.context.OrderItem;
import io.shardingsphere.core.parsing.parser.context.limit.Limit;
import io.shardingsphere.core.parsing.parser.sql.SQLStatement;
import io.shardingsphere.core.parsing.parser.sql.dml.insert.InsertStatement;
import io.shardingsphere.core.parsing.parser.sql.dql.select.SelectStatement;
import io.shardingsphere.core.parsing.parser.token.IndexToken;
import io.shardingsphere.core.parsing.parser.token.InsertColumnToken;
import io.shardingsphere.core.parsing.parser.token.InsertValuesToken;
import io.shardingsphere.core.parsing.parser.token.ItemsToken;
import io.shardingsphere.core.parsing.parser.token.OffsetToken;
import io.shardingsphere.core.parsing.parser.token.OrderByToken;
import io.shardingsphere.core.parsing.parser.token.RowCountToken;
import io.shardingsphere.core.parsing.parser.token.SQLToken;
import io.shardingsphere.core.parsing.parser.token.SchemaToken;
import io.shardingsphere.core.parsing.parser.token.TableToken;
import io.shardingsphere.core.metadata.datasource.ShardingDataSourceMetaData;
import io.shardingsphere.core.rewrite.placeholder.IndexPlaceholder;
import io.shardingsphere.core.rewrite.placeholder.InsertValuesPlaceholder;
import io.shardingsphere.core.rewrite.placeholder.SchemaPlaceholder;
import io.shardingsphere.core.rewrite.placeholder.TablePlaceholder;
import io.shardingsphere.core.routing.SQLUnit;
import io.shardingsphere.core.routing.type.RoutingTable;
import io.shardingsphere.core.routing.type.TableUnit;
import io.shardingsphere.core.rule.BindingTableRule;
import io.shardingsphere.core.rule.ShardingRule;
import io.shardingsphere.core.util.SQLUtil;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
/**
* SQL rewrite engine.
*
* Rewrite logic SQL to actual SQL, should rewrite table name and optimize something.
*
* @author zhangliang
* @author maxiaoguang
* @author panjuan
*/
public final class SQLRewriteEngine {
private final ShardingRule shardingRule;
private final String originalSQL;
private final DatabaseType databaseType;
private final List sqlTokens = new LinkedList<>();
private final SQLStatement sqlStatement;
private final ShardingConditions shardingConditions;
private final List parameters;
/**
* Constructs SQL rewrite engine.
*
* @param shardingRule databases and tables sharding rule
* @param originalSQL original SQL
* @param databaseType database type
* @param sqlStatement SQL statement
* @param shardingConditions sharding conditions
* @param parameters parameters
*/
public SQLRewriteEngine(final ShardingRule shardingRule, final String originalSQL, final DatabaseType databaseType,
final SQLStatement sqlStatement, final ShardingConditions shardingConditions, final List parameters) {
this.shardingRule = shardingRule;
this.originalSQL = originalSQL;
this.databaseType = databaseType;
this.sqlStatement = sqlStatement;
this.shardingConditions = shardingConditions;
this.parameters = parameters;
sqlTokens.addAll(sqlStatement.getSqlTokens());
}
/**
* rewrite SQL.
*
* @param isRewriteLimit is rewrite limit
* @return SQL builder
*/
public SQLBuilder rewrite(final boolean isRewriteLimit) {
SQLBuilder result = new SQLBuilder(parameters);
if (sqlTokens.isEmpty()) {
result.appendLiterals(originalSQL);
return result;
}
int count = 0;
sortByBeginPosition();
for (SQLToken each : sqlTokens) {
if (0 == count) {
result.appendLiterals(originalSQL.substring(0, each.getBeginPosition()));
}
if (each instanceof TableToken) {
appendTablePlaceholder(result, (TableToken) each, count, sqlTokens);
} else if (each instanceof SchemaToken) {
appendSchemaPlaceholder(result, (SchemaToken) each, count, sqlTokens);
} else if (each instanceof IndexToken) {
appendIndexPlaceholder(result, (IndexToken) each, count, sqlTokens);
} else if (each instanceof ItemsToken) {
appendItemsToken(result, (ItemsToken) each, count, sqlTokens);
} else if (each instanceof InsertValuesToken) {
appendInsertValuesToken(result, (InsertValuesToken) each, count, sqlTokens);
} else if (each instanceof RowCountToken) {
appendLimitRowCount(result, (RowCountToken) each, count, sqlTokens, isRewriteLimit);
} else if (each instanceof OffsetToken) {
appendLimitOffsetToken(result, (OffsetToken) each, count, sqlTokens, isRewriteLimit);
} else if (each instanceof OrderByToken) {
appendOrderByToken(result, count, sqlTokens);
} else if (each instanceof InsertColumnToken) {
appendSymbolToken(result, (InsertColumnToken) each, count, sqlTokens);
}
count++;
}
return result;
}
private void sortByBeginPosition() {
Collections.sort(sqlTokens, new Comparator() {
@Override
public int compare(final SQLToken o1, final SQLToken o2) {
return o1.getBeginPosition() - o2.getBeginPosition();
}
});
}
private void appendTablePlaceholder(final SQLBuilder sqlBuilder, final TableToken tableToken, final int count, final List sqlTokens) {
sqlBuilder.appendPlaceholder(new TablePlaceholder(tableToken.getTableName().toLowerCase(), tableToken.getOriginalLiterals()));
int beginPosition = tableToken.getBeginPosition() + tableToken.getSkippedSchemaNameLength() + tableToken.getOriginalLiterals().length();
appendRest(sqlBuilder, count, sqlTokens, beginPosition);
}
private void appendSchemaPlaceholder(final SQLBuilder sqlBuilder, final SchemaToken schemaToken, final int count, final List sqlTokens) {
sqlBuilder.appendPlaceholder(new SchemaPlaceholder(schemaToken.getSchemaName().toLowerCase(), schemaToken.getTableName().toLowerCase()));
int beginPosition = schemaToken.getBeginPosition() + schemaToken.getOriginalLiterals().length();
appendRest(sqlBuilder, count, sqlTokens, beginPosition);
}
private void appendIndexPlaceholder(final SQLBuilder sqlBuilder, final IndexToken indexToken, final int count, final List sqlTokens) {
String indexName = indexToken.getIndexName().toLowerCase();
String logicTableName = indexToken.getTableName().toLowerCase();
if (Strings.isNullOrEmpty(logicTableName)) {
logicTableName = shardingRule.getLogicTableName(indexName);
}
sqlBuilder.appendPlaceholder(new IndexPlaceholder(indexName, logicTableName));
int beginPosition = indexToken.getBeginPosition() + indexToken.getOriginalLiterals().length();
appendRest(sqlBuilder, count, sqlTokens, beginPosition);
}
private void appendItemsToken(final SQLBuilder sqlBuilder, final ItemsToken itemsToken, final int count, final List sqlTokens) {
for (int i = 0; i < itemsToken.getItems().size(); i++) {
if (itemsToken.isFirstOfItemsSpecial() && 0 == i) {
sqlBuilder.appendLiterals(SQLUtil.getOriginalValue(itemsToken.getItems().get(i), databaseType));
} else {
sqlBuilder.appendLiterals(", ");
sqlBuilder.appendLiterals(SQLUtil.getOriginalValue(itemsToken.getItems().get(i), databaseType));
}
}
appendRest(sqlBuilder, count, sqlTokens, itemsToken.getBeginPosition());
}
private void appendInsertValuesToken(final SQLBuilder sqlBuilder, final InsertValuesToken insertValuesToken, final int count, final List sqlTokens) {
sqlBuilder.appendPlaceholder(new InsertValuesPlaceholder(insertValuesToken.getTableName().toLowerCase(), shardingConditions));
appendRest(sqlBuilder, count, sqlTokens, ((InsertStatement) sqlStatement).getInsertValuesListLastPosition());
}
private void appendLimitRowCount(final SQLBuilder sqlBuilder, final RowCountToken rowCountToken, final int count, final List sqlTokens, final boolean isRewrite) {
SelectStatement selectStatement = (SelectStatement) sqlStatement;
Limit limit = selectStatement.getLimit();
if (!isRewrite) {
sqlBuilder.appendLiterals(String.valueOf(rowCountToken.getRowCount()));
} else if ((!selectStatement.getGroupByItems().isEmpty() || !selectStatement.getAggregationSelectItems().isEmpty()) && !selectStatement.isSameGroupByAndOrderByItems()) {
sqlBuilder.appendLiterals(String.valueOf(Integer.MAX_VALUE));
} else {
sqlBuilder.appendLiterals(String.valueOf(limit.isNeedRewriteRowCount() ? rowCountToken.getRowCount() + limit.getOffsetValue() : rowCountToken.getRowCount()));
}
int beginPosition = rowCountToken.getBeginPosition() + String.valueOf(rowCountToken.getRowCount()).length();
appendRest(sqlBuilder, count, sqlTokens, beginPosition);
}
private void appendLimitOffsetToken(final SQLBuilder sqlBuilder, final OffsetToken offsetToken, final int count, final List sqlTokens, final boolean isRewrite) {
sqlBuilder.appendLiterals(isRewrite ? "0" : String.valueOf(offsetToken.getOffset()));
int beginPosition = offsetToken.getBeginPosition() + String.valueOf(offsetToken.getOffset()).length();
appendRest(sqlBuilder, count, sqlTokens, beginPosition);
}
private void appendOrderByToken(final SQLBuilder sqlBuilder, final int count, final List sqlTokens) {
SelectStatement selectStatement = (SelectStatement) sqlStatement;
StringBuilder orderByLiterals = new StringBuilder();
orderByLiterals.append(" ").append(DefaultKeyword.ORDER).append(" ").append(DefaultKeyword.BY).append(" ");
int i = 0;
for (OrderItem each : selectStatement.getOrderByItems()) {
String columnLabel = Strings.isNullOrEmpty(each.getColumnLabel()) ? String.valueOf(each.getIndex()) : SQLUtil.getOriginalValue(each.getColumnLabel(), databaseType);
if (0 == i) {
orderByLiterals.append(columnLabel).append(" ").append(each.getOrderDirection().name());
} else {
orderByLiterals.append(",").append(columnLabel).append(" ").append(each.getOrderDirection().name());
}
i++;
}
orderByLiterals.append(" ");
sqlBuilder.appendLiterals(orderByLiterals.toString());
int beginPosition = ((SelectStatement) sqlStatement).getGroupByLastPosition();
appendRest(sqlBuilder, count, sqlTokens, beginPosition);
}
private void appendSymbolToken(final SQLBuilder sqlBuilder, final InsertColumnToken insertColumnToken, final int count, final List sqlTokens) {
sqlBuilder.appendLiterals(insertColumnToken.getColumnName());
appendRest(sqlBuilder, count, sqlTokens, insertColumnToken.getBeginPosition());
}
private void appendRest(final SQLBuilder sqlBuilder, final int count, final List sqlTokens, final int beginPosition) {
int endPosition = sqlTokens.size() - 1 == count ? originalSQL.length() : sqlTokens.get(count + 1).getBeginPosition();
sqlBuilder.appendLiterals(originalSQL.substring(beginPosition, endPosition));
}
/**
* Generate SQL string.
*
* @param tableUnit route table unit
* @param sqlBuilder SQL builder
* @param shardingDataSourceMetaData sharding data source meta data
* @return SQL unit
*/
public SQLUnit generateSQL(final TableUnit tableUnit, final SQLBuilder sqlBuilder, final ShardingDataSourceMetaData shardingDataSourceMetaData) {
return sqlBuilder.toSQL(tableUnit, getTableTokens(tableUnit), shardingRule, shardingDataSourceMetaData);
}
private Map getTableTokens(final TableUnit tableUnit) {
Map result = new HashMap<>();
for (RoutingTable routingTable : tableUnit.getRoutingTables()) {
String logicTableName = routingTable.getLogicTableName().toLowerCase();
result.put(logicTableName, routingTable.getActualTableName());
Optional bindingTableRule = shardingRule.findBindingTableRule(logicTableName);
if (bindingTableRule.isPresent()) {
result.putAll(getBindingTableTokens(tableUnit.getDataSourceName(), routingTable, bindingTableRule.get()));
}
}
return result;
}
private Map getBindingTableTokens(final String dataSourceName, final RoutingTable routingTable, final BindingTableRule bindingTableRule) {
Map result = new HashMap<>();
for (String eachTable : sqlStatement.getTables().getTableNames()) {
String tableName = eachTable.toLowerCase();
if (!tableName.equals(routingTable.getLogicTableName().toLowerCase()) && bindingTableRule.hasLogicTable(tableName)) {
result.put(tableName, bindingTableRule.getBindingActualTable(dataSourceName, tableName, routingTable.getActualTableName()));
}
}
return result;
}
}
