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.sql.util;
  
  import org.apache.calcite.sql.SqlFunctionCategory;
  import org.apache.calcite.sql.SqlIdentifier;
  import org.apache.calcite.sql.SqlOperator;
  import org.apache.calcite.sql.SqlOperatorTable;
  import org.apache.calcite.sql.SqlSyntax;
  import org.apache.calcite.sql.validate.SqlNameMatcher;
  
  import com.google.common.collect.ImmutableList;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import java.util.ArrayList;
  import java.util.List;
  
  /**
   * ChainedSqlOperatorTable implements the {@link SqlOperatorTable} interface by
   * chaining together any number of underlying operator table instances.
   *
   * <p>To create, call {@link SqlOperatorTables#chain}.
   */
  public class ChainedSqlOperatorTable implements SqlOperatorTable {
    //~ Instance fields --------------------------------------------------------
  
    protected final List<SqlOperatorTable> tableList;
  
    //~ Constructors -----------------------------------------------------------
  
    @Deprecated // to be removed before 2.0
    public ChainedSqlOperatorTable(List<SqlOperatorTable> tableList) {
      this(ImmutableList.copyOf(tableList));
    }
  
    /** Internal constructor; call {@link SqlOperatorTables#chain}. */
    protected ChainedSqlOperatorTable(ImmutableList<SqlOperatorTable> tableList) {
      this.tableList = ImmutableList.copyOf(tableList);
    }
  
    //~ Methods ----------------------------------------------------------------
  
    @Deprecated // to be removed before 2.0
    public void add(SqlOperatorTable table) {
      if (!tableList.contains(table)) {
        tableList.add(table);
      }
    }
  
    @Override public void lookupOperatorOverloads(SqlIdentifier opName,
        @Nullable SqlFunctionCategory category, SqlSyntax syntax,
        List<SqlOperator> operatorList, SqlNameMatcher nameMatcher) {
      for (SqlOperatorTable table : tableList) {
        table.lookupOperatorOverloads(opName, category, syntax, operatorList,
            nameMatcher);
      }
    }
  
    @Override public List<SqlOperator> getOperatorList() {
      List<SqlOperator> list = new ArrayList<>();
      for (SqlOperatorTable table : tableList) {
        list.addAll(table.getOperatorList());
      }
      return list;
    }
  }
  