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.linq4j.tree;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import java.util.Objects;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * Represents a "for-each" loop, "for (T v : iterable) { f(v); }".
   */
  public class ForEachStatement extends Statement {
    public final ParameterExpression parameter;
    public final Expression iterable;
    public final Statement body;
  
    /** Cached hash code for the expression. */
    private int hash;
  
    public ForEachStatement(ParameterExpression parameter, Expression iterable,
        Statement body) {
      super(ExpressionType.ForEach, Void.TYPE);
      this.parameter = requireNonNull(parameter, "parameter");
      this.iterable = requireNonNull(iterable, "iterable");
      this.body = requireNonNull(body, "body"); // may be empty block, not null
    }
  
    @Override public ForEachStatement accept(Shuttle shuttle) {
      shuttle = shuttle.preVisit(this);
      final Expression iterable1 = iterable.accept(shuttle);
      final Statement body1 = body.accept(shuttle);
      return shuttle.visit(this, parameter, iterable1, body1);
    }
  
    @Override public <R> R accept(Visitor<R> visitor) {
      return visitor.visit(this);
    }
  
    @Override void accept0(ExpressionWriter writer) {
      writer.append("for (")
          .append(parameter.type)
          .append(" ")
          .append(parameter)
          .append(" : ")
          .append(iterable)
          .append(") ")
          .append(Blocks.toBlock(body));
    }
  
    @Override public boolean equals(@Nullable Object o) {
      return this == o
          || o instanceof ForEachStatement
          && parameter.equals(((ForEachStatement) o).parameter)
          && iterable.equals(((ForEachStatement) o).iterable)
          && body.equals(((ForEachStatement) o).body);
    }
  
    @Override public int hashCode() {
      int result = hash;
      if (result == 0) {
        result =
            Objects.hash(nodeType, type, parameter, iterable, body);
        if (result == 0) {
          result = 1;
        }
        hash = result;
      }
      return result;
    }
  }
  