content: /*
   * 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.calcite.rel;
  
  import org.apache.calcite.plan.RelOptCluster;
  import org.apache.calcite.plan.RelOptTable;
  import org.apache.calcite.plan.RelTraitSet;
  import org.apache.calcite.rel.core.AggregateCall;
  import org.apache.calcite.rel.type.RelDataType;
  import org.apache.calcite.rex.RexLiteral;
  import org.apache.calcite.rex.RexNode;
  import org.apache.calcite.util.ImmutableBitSet;
  
  import com.google.common.collect.ImmutableList;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import java.math.BigDecimal;
  import java.util.List;
  
  /**
   * Context from which a relational expression can initialize itself,
   * reading from a serialized form of the relational expression.
   */
  public interface RelInput {
    RelOptCluster getCluster();
  
    RelTraitSet getTraitSet();
  
    RelOptTable getTable(String table);
  
    /**
     * Returns the input relational expression. Throws if there is not precisely
     * one input.
     */
    RelNode getInput();
  
    List<RelNode> getInputs();
  
    /**
     * Returns an expression.
     */
    @Nullable RexNode getExpression(String tag);
  
    ImmutableBitSet getBitSet(String tag);
  
    @Nullable List<ImmutableBitSet> getBitSetList(String tag);
  
    List<AggregateCall> getAggregateCalls(String tag);
  
    @Nullable Object get(String tag);
  
    /**
     * Returns a {@code string} value.
     * Throws if wrong type, returns null if not present.
     */
    @Nullable String getString(String tag);
  
    /**
     * Returns a {@code float} value.
     * Throws if not present or wrong type.
     */
    float getFloat(String tag);
  
    /**
     * Returns a {@code BigDecimal} value.
     * Throws if not present or wrong type.
     */
    BigDecimal getBigDecimal(String tag);
  
    /**
     * Returns an enum value. Throws if not a valid member.
     */
    <E extends Enum<E>> @Nullable E getEnum(String tag, Class<E> enumClass);
  
    @Nullable List<RexNode> getExpressionList(String tag);
  
    @Nullable List<String> getStringList(String tag);
  
    @Nullable List<Integer> getIntegerList(String tag);
  
    @Nullable List<List<Integer>> getIntegerListList(String tag);
  
    RelDataType getRowType(String tag);
  
    RelDataType getRowType(String expressionsTag, String fieldsTag);
  
    RelCollation getCollation();
  
    RelDistribution getDistribution();
  
    ImmutableList<ImmutableList<RexLiteral>> getTuples(String tag);
  
    boolean getBoolean(String tag, boolean default_);
  }
  