Java tutorial
/* * 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.tree; import com.google.common.collect.ImmutableSet; import java.util.List; import java.util.Objects; import java.util.Optional; import java.util.Set; import static com.google.common.base.MoreObjects.toStringHelper; public class SimpleGroupBy extends GroupingElement { private final List<Expression> columns; public SimpleGroupBy(List<Expression> simpleGroupByExpressions) { this(Optional.empty(), simpleGroupByExpressions); } public SimpleGroupBy(NodeLocation location, List<Expression> simpleGroupByExpressions) { this(Optional.of(location), simpleGroupByExpressions); } private SimpleGroupBy(Optional<NodeLocation> location, List<Expression> simpleGroupByExpressions) { super(location); this.columns = simpleGroupByExpressions; } public List<Expression> getColumnExpressions() { return columns; } @Override public Set<Set<Expression>> enumerateGroupingSets() { return ImmutableSet.of(ImmutableSet.copyOf(columns)); } @Override public boolean equals(Object o) { if (this == o) { return true; } if (o == null || getClass() != o.getClass()) { return false; } SimpleGroupBy that = (SimpleGroupBy) o; return Objects.equals(columns, that.columns); } @Override public int hashCode() { return Objects.hash(columns); } @Override public String toString() { return toStringHelper(this).add("columns", columns).toString(); } }