/*
 * 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.phoenix.iterate;

import java.sql.SQLException;
import java.util.List;
import org.apache.phoenix.compile.ExplainPlanAttributes.ExplainPlanAttributesBuilder;
import org.apache.phoenix.schema.tuple.Tuple;

/**
 * Iterates through tuples up to a limit
 * @since 1.2
 */
public class LimitingResultIterator extends DelegateResultIterator {
  private int rowCount;
  private final int limit;

  public LimitingResultIterator(ResultIterator delegate, int limit) {
    super(delegate);
    this.limit = limit;
  }

  @Override
  public Tuple next() throws SQLException {
    if (rowCount++ >= limit) {
      close(); // Free resources early
      return null;
    }
    return super.next();
  }

  @Override
  public void explain(List<String> planSteps) {
    super.explain(planSteps);
    planSteps.add("CLIENT " + limit + " ROW LIMIT");
  }

  @Override
  public void explain(List<String> planSteps,
    ExplainPlanAttributesBuilder explainPlanAttributesBuilder) {
    super.explain(planSteps, explainPlanAttributesBuilder);
    explainPlanAttributesBuilder.setClientRowLimit(limit);
    planSteps.add("CLIENT " + limit + " ROW LIMIT");
  }

  @Override
  public String toString() {
    return "LimitingResultIterator [rowCount=" + rowCount + ", limit=" + limit + "]";
  }
}
