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.interpreter;
  
  import org.apache.calcite.DataContext;
  import org.apache.calcite.linq4j.Enumerable;
  import org.apache.calcite.rel.RelNode;
  import org.apache.calcite.runtime.ArrayBindable;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  /**
   * Utilities relating to {@link org.apache.calcite.interpreter.Interpreter}
   * and {@link org.apache.calcite.interpreter.InterpretableConvention}.
   */
  public class Interpreters {
    private Interpreters() {}
  
    /** Creates a {@link org.apache.calcite.runtime.Bindable} that interprets a
     * given relational expression. */
    public static ArrayBindable bindable(final RelNode rel) {
      if (rel instanceof ArrayBindable) {
        // E.g. if rel instanceof BindableRel
        return (ArrayBindable) rel;
      }
      return new ArrayBindable() {
        @Override public Enumerable<@Nullable Object[]> bind(DataContext dataContext) {
          return new Interpreter(dataContext, rel);
        }
  
        @Override public Class<Object[]> getElementType() {
          return Object[].class;
        }
      };
    }
  }
  