| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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 org.apache.druid.sql.calcite.planner; |
| |
| import com.google.common.base.Preconditions; |
| import org.apache.calcite.rel.core.Sort; |
| import org.apache.calcite.rex.RexBuilder; |
| import org.apache.calcite.rex.RexLiteral; |
| import org.apache.calcite.rex.RexNode; |
| import org.apache.calcite.sql.type.BasicSqlType; |
| import org.apache.calcite.sql.type.SqlTypeName; |
| |
| import javax.annotation.Nullable; |
| import java.util.Objects; |
| |
| /** |
| * Represents an offset and a limit. |
| */ |
| public class OffsetLimit |
| { |
| private final long offset; |
| |
| @Nullable |
| private final Long limit; |
| |
| OffsetLimit(long offset, @Nullable Long limit) |
| { |
| Preconditions.checkArgument(offset >= 0, "offset >= 0"); |
| Preconditions.checkArgument(limit == null || limit >= 0, "limit == null || limit >= 0"); |
| |
| this.offset = offset; |
| this.limit = limit; |
| } |
| |
| public static OffsetLimit none() |
| { |
| return new OffsetLimit(0, null); |
| } |
| |
| public static OffsetLimit fromSort(Sort sort) |
| { |
| final long offset = sort.offset == null ? 0 : (long) RexLiteral.intValue(sort.offset); |
| final Long limit = sort.fetch == null ? null : (long) RexLiteral.intValue(sort.fetch); |
| return new OffsetLimit(offset, limit); |
| } |
| |
| public boolean hasOffset() |
| { |
| return offset > 0; |
| } |
| |
| public long getOffset() |
| { |
| return offset; |
| } |
| |
| public boolean hasLimit() |
| { |
| return limit != null; |
| } |
| |
| public long getLimit() |
| { |
| Preconditions.checkState(limit != null, "limit is not present"); |
| return limit; |
| } |
| |
| @Nullable |
| public RexNode getOffsetAsRexNode(final RexBuilder builder) |
| { |
| if (offset == 0) { |
| return null; |
| } else { |
| return builder.makeLiteral( |
| offset, |
| new BasicSqlType(DruidTypeSystem.INSTANCE, SqlTypeName.BIGINT), |
| false |
| ); |
| } |
| } |
| |
| @Nullable |
| public RexNode getLimitAsRexNode(final RexBuilder builder) |
| { |
| if (limit == null) { |
| return null; |
| } else { |
| return builder.makeLiteral( |
| limit, |
| new BasicSqlType(DruidTypeSystem.INSTANCE, SqlTypeName.BIGINT), |
| false |
| ); |
| } |
| } |
| |
| /** |
| * Return a new instance that represents applying this one first, then the {@param next} one. |
| */ |
| public OffsetLimit andThen(final OffsetLimit next) |
| { |
| final Long newLimit; |
| |
| if (limit == null && next.limit == null) { |
| // Neither has a limit => no limit overall. |
| newLimit = null; |
| } else if (limit == null) { |
| // Outer limit only. |
| newLimit = next.limit; |
| } else if (next.limit == null) { |
| // Inner limit only. |
| newLimit = Math.max(0, limit - next.offset); |
| } else { |
| // Both outer and inner limit. |
| newLimit = Math.max(0, Math.min(limit - next.offset, next.limit)); |
| } |
| |
| return new OffsetLimit(offset + next.offset, newLimit); |
| } |
| |
| @Override |
| public boolean equals(Object o) |
| { |
| if (this == o) { |
| return true; |
| } |
| if (o == null || getClass() != o.getClass()) { |
| return false; |
| } |
| OffsetLimit that = (OffsetLimit) o; |
| return Objects.equals(offset, that.offset) && |
| Objects.equals(limit, that.limit); |
| } |
| |
| @Override |
| public int hashCode() |
| { |
| return Objects.hash(offset, limit); |
| } |
| |
| @Override |
| public String toString() |
| { |
| return "OffsetLimit{" + |
| "offset=" + offset + |
| ", limit=" + limit + |
| '}'; |
| } |
| } |