refactor limit for rewrite module (90083bac) · Commits · SUMMER2020 / students / proj-2004142

sharding-jdbc-core/src/main/java/com/dangdang/ddframe/rdb/sharding/parsing/parser/context/LimitContext.java

+43 −2

Original line number	Diff line number	Diff line
		@@ -17,8 +17,12 @@

		package com.dangdang.ddframe.rdb.sharding.parsing.parser.context;

		import com.dangdang.ddframe.rdb.sharding.parsing.parser.exception.SQLParsingException;
		import com.google.common.base.Optional;
		import lombok.Getter;
		import lombok.Setter;

		import java.util.List;

		/**
		* 分页上下文.
		@@ -26,11 +30,12 @@ import lombok.Getter;
		* @author zhangliang
		*/
		@Getter
		@Setter
		public final class LimitContext {

		private final int rowCount;
		private int rowCount;

		private final Optional<Integer> offset;
		private Optional<Integer> offset;

		private final int rowCountParameterIndex;

		@@ -50,7 +55,43 @@ public final class LimitContext {
		this.rowCountParameterIndex = rowCountParameterIndex;
		}

		/**
		* 获取分页偏移量.
		*
		* @return 分页偏移量
		*/
		public int getOffset() {
		return offset.isPresent() ? offset.get() : 0;
		}

		/**
		* 填充改写分页参数.
		*
		* @param parameters 参数
		*/
		public void processParameters(final List<Object> parameters) {
		fill(parameters);
		rewrite(parameters);
		}

		private void fill(final List<Object> parameters) {
		int offset = -1 == offsetParameterIndex ? getOffset() : (int) parameters.get(offsetParameterIndex);
		int rowCount = -1 == rowCountParameterIndex ? this.rowCount : (int) parameters.get(rowCountParameterIndex);
		this.offset = Optional.of(offset);
		this.rowCount = rowCount;
		if (offset < 0 \|\| rowCount < 0) {
		throw new SQLParsingException("LIMIT offset and row count can not be a negative value.");
		}
		}

		private void rewrite(final List<Object> parameters) {
		int rewriteOffset = 0;
		int rewriteRowCount = getOffset() + rowCount;
		if (offsetParameterIndex > -1) {
		parameters.set(offsetParameterIndex, rewriteOffset);
		}
		if (rowCountParameterIndex > -1) {
		parameters.set(rowCountParameterIndex, rewriteRowCount);
		}
		}
		}

sharding-jdbc-core/src/main/java/com/dangdang/ddframe/rdb/sharding/rewrite/LimitUtils.java

deleted100644 → 0

+0 −49

Original line number	Diff line number	Diff line
		/*
		* Copyright 1999-2015 dangdang.com.
		* <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 com.dangdang.ddframe.rdb.sharding.rewrite;

		import com.dangdang.ddframe.rdb.sharding.parsing.parser.context.LimitContext;
		import com.dangdang.ddframe.rdb.sharding.parsing.parser.context.SQLContext;
		import com.dangdang.ddframe.rdb.sharding.parsing.parser.exception.SQLParsingException;

		import java.util.List;

		/**
		* 补列工具类.
		*
		* @author zhangliang
		*/
		public final class LimitUtils {

		/**
		* 追加分页.
		*
		* @param sqlContext SQL上下文
		* @param parameters 参数
		*/
		public static void appendLimit(final SQLContext sqlContext, final List<Object> parameters) {
		int offset = -1 == sqlContext.getLimitContext().getOffsetParameterIndex()
		? sqlContext.getLimitContext().getOffset() : (int) parameters.get(sqlContext.getLimitContext().getOffsetParameterIndex());
		int rowCount = -1 == sqlContext.getLimitContext().getRowCountParameterIndex()
		? sqlContext.getLimitContext().getRowCount() : (int) parameters.get(sqlContext.getLimitContext().getRowCountParameterIndex());
		sqlContext.setLimitContext(new LimitContext(offset, rowCount, sqlContext.getLimitContext().getOffsetParameterIndex(), sqlContext.getLimitContext().getRowCountParameterIndex()));
		if (offset < 0 \|\| rowCount < 0) {
		throw new SQLParsingException("LIMIT offset and row count can not be a negative value.");
		}
		}
		}

sharding-jdbc-core/src/main/java/com/dangdang/ddframe/rdb/sharding/rewrite/SQLRewriteEngine.java

+2 −2

Original line number	Diff line number	Diff line
		@@ -127,14 +127,14 @@ public final class SQLRewriteEngine {
		}

		private void appendLimitRowCount(final SQLBuilder sqlBuilder, final RowCountLimitToken rowCountLimitToken, final int count, final List<SQLToken> sqlTokens) {
		sqlBuilder.appendToken(RowCountLimitToken.COUNT_NAME, rowCountLimitToken.getRowCount() + "");
		sqlBuilder.appendToken(RowCountLimitToken.COUNT_NAME, rowCountLimitToken.getRowCount() + limit.getOffset() + "");
		int beginPosition = rowCountLimitToken.getBeginPosition() + (rowCountLimitToken.getRowCount() + "").length();
		int endPosition = sqlTokens.size() - 1 == count ? originalSQL.length() : sqlTokens.get(count + 1).getBeginPosition();
		sqlBuilder.append(originalSQL.substring(beginPosition, endPosition));
		}

		private void appendLimitOffsetToken(final SQLBuilder sqlBuilder, final OffsetLimitToken offsetLimitToken, final int count, final List<SQLToken> sqlTokens) {
		sqlBuilder.appendToken(OffsetLimitToken.OFFSET_NAME, offsetLimitToken.getOffset() + "");
		sqlBuilder.appendToken(OffsetLimitToken.OFFSET_NAME, "0");
		int beginPosition = offsetLimitToken.getBeginPosition() + (offsetLimitToken.getOffset() + "").length();
		int endPosition = sqlTokens.size() - 1 == count ? originalSQL.length() : sqlTokens.get(count + 1).getBeginPosition();
		sqlBuilder.append(originalSQL.substring(beginPosition, endPosition));

sharding-jdbc-core/src/main/java/com/dangdang/ddframe/rdb/sharding/router/SQLRouteEngine.java

+13 −22

Original line number	Diff line number	Diff line
		@@ -36,7 +36,6 @@ import com.dangdang.ddframe.rdb.sharding.parsing.parser.token.OffsetLimitToken;
		import com.dangdang.ddframe.rdb.sharding.parsing.parser.token.RowCountLimitToken;
		import com.dangdang.ddframe.rdb.sharding.rewrite.DerivedColumnUtils;
		import com.dangdang.ddframe.rdb.sharding.rewrite.GenerateKeysUtils;
		import com.dangdang.ddframe.rdb.sharding.rewrite.LimitUtils;
		import com.dangdang.ddframe.rdb.sharding.rewrite.SQLBuilder;
		import com.dangdang.ddframe.rdb.sharding.rewrite.SQLRewriteEngine;
		import com.dangdang.ddframe.rdb.sharding.router.binding.BindingTablesRouter;
		@@ -104,7 +103,7 @@ public final class SQLRouteEngine {
		DerivedColumnUtils.appendDerivedColumns((SelectSQLContext) result);
		}
		if (null != result.getLimitContext()) {
		LimitUtils.appendLimit(result, parameters);
		result.getLimitContext().processParameters(parameters);
		}
		return result;
		}
		@@ -169,26 +168,18 @@ public final class SQLRouteEngine {
		private void amendSQLAccordingToRouteResult(final List<Object> parameters, final SQLRouteResult sqlRouteResult, final SQLRewriteEngine sqlRewriteEngine) {
		LimitContext limit = sqlRouteResult.getSqlContext().getLimitContext();
		SQLBuilder sqlBuilder = sqlRewriteEngine.rewrite();
		if (null != limit) {
		if (1 == sqlRouteResult.getExecutionUnits().size()) {
		if (null == limit \|\| 1 != sqlRouteResult.getExecutionUnits().size()) {
		return;
		}
		if (limit.getOffsetParameterIndex() > -1) {
		parameters.set(limit.getOffsetParameterIndex(), limit.getOffset());
		} else {
		sqlBuilder.buildSQL(OffsetLimitToken.OFFSET_NAME, String.valueOf(limit.getOffset()));
		}
		if (limit.getRowCountParameterIndex() > -1) {
		parameters.set(limit.getRowCountParameterIndex(), limit.getRowCount());
		}
		} else {
		int offset = 0;
		int rowCount = limit.getOffset() + limit.getRowCount();
		if (limit.getOffsetParameterIndex() > -1) {
		parameters.set(limit.getOffsetParameterIndex(), offset);
		}
		if (limit.getRowCountParameterIndex() > -1) {
		parameters.set(limit.getRowCountParameterIndex(), rowCount);
		}
		sqlBuilder.buildSQL(OffsetLimitToken.OFFSET_NAME, String.valueOf(offset));
		sqlBuilder.buildSQL(RowCountLimitToken.COUNT_NAME, String.valueOf(rowCount));
		}
		sqlBuilder.buildSQL(RowCountLimitToken.COUNT_NAME, String.valueOf(limit.getRowCount()));
		}
		}
		}