/* * 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 com.facebook.presto.sql.planner.plan; import com.facebook.presto.sql.planner.Symbol; import com.fasterxml.jackson.annotation.JsonCreator; import com.fasterxml.jackson.annotation.JsonProperty; import com.google.common.collect.ImmutableList; import com.google.common.collect.Iterables; import javax.annotation.concurrent.Immutable; import java.util.List; import static com.google.common.base.Preconditions.checkArgument; import static java.util.Objects.requireNonNull; @Immutable public class LimitNode extends PlanNode { private final PlanNode source; private final long count; private final boolean partial; @JsonCreator public LimitNode( @JsonProperty("id") PlanNodeId id, @JsonProperty("source") PlanNode source, @JsonProperty("count") long count, @JsonProperty("partial") boolean partial) { super(id); this.partial = partial; requireNonNull(source, "source is null"); checkArgument(count >= 0, "count must be greater than or equal to zero"); this.source = source; this.count = count; } @Override public List<PlanNode> getSources() { return ImmutableList.of(source); } @JsonProperty public PlanNode getSource() { return source; } @JsonProperty public long getCount() { return count; } @JsonProperty public boolean isPartial() { return partial; } @Override public List<Symbol> getOutputSymbols() { return source.getOutputSymbols(); } @Override public <C, R> R accept(PlanVisitor<C, R> visitor, C context) { return visitor.visitLimit(this, context); } @Override public PlanNode replaceChildren(List<PlanNode> newChildren) { return new LimitNode(getId(), Iterables.getOnlyElement(newChildren), count, isPartial()); } }