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.apache.calcite.linq4j.Ord;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import java.util.List;
  import java.util.Objects;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * Represents an infinite loop. It can be exited with "break".
   */
  public class ForStatement extends Statement {
    public final List<DeclarationStatement> declarations;
    public final @Nullable Expression condition;
    public final @Nullable Expression post;
    public final Statement body;
    /** Cached hash code for the expression. */
    private int hash;
  
    public ForStatement(List<DeclarationStatement> declarations,
        @Nullable Expression condition, @Nullable Expression post,
        Statement body) {
      super(ExpressionType.For, Void.TYPE);
      this.declarations =
          requireNonNull(declarations, "declarations"); // may be empty
      this.condition = condition;
      this.post = post;
      this.body = requireNonNull(body, "body"); // may be empty block
    }
  
    @Override public ForStatement accept(Shuttle shuttle) {
      shuttle = shuttle.preVisit(this);
      List<DeclarationStatement> decls1 =
          Expressions.acceptDeclarations(declarations, shuttle);
      final Expression condition1 =
          condition == null ? null : condition.accept(shuttle);
      final Expression post1 = post == null ? null : post.accept(shuttle);
      final Statement body1 = body.accept(shuttle);
      return shuttle.visit(this, decls1, condition1, post1, body1);
    }
  
    @Override public <R> R accept(Visitor<R> visitor) {
      return visitor.visit(this);
    }
  
    @Override void accept0(ExpressionWriter writer) {
      writer.append("for (");
      for (Ord<DeclarationStatement> declaration : Ord.zip(declarations)) {
        declaration.e.accept2(writer, declaration.i == 0);
      }
      writer.append("; ");
      if (condition != null) {
        writer.append(condition);
      }
      writer.append("; ");
      if (post != null) {
        writer.append(post);
      }
      writer.append(") ").append(Blocks.toBlock(body));
    }
  
    @Override public boolean equals(@Nullable Object o) {
      if (this == o) {
        return true;
      }
      if (o == null || getClass() != o.getClass()) {
        return false;
      }
      if (!super.equals(o)) {
        return false;
      }
  
      ForStatement that = (ForStatement) o;
      return body.equals(that.body)
          && Objects.equals(condition, that.condition)
          && declarations.equals(that.declarations)
          && Objects.equals(post, that.post);
    }
  
    @Override public int hashCode() {
      int result = hash;
      if (result == 0) {
        result =
            Objects.hash(nodeType, type, declarations, condition, post, body);
        if (result == 0) {
          result = 1;
        }
        hash = result;
      }
      return result;
    }
  }
  