/*
 * 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.compile.SequenceManager;
import org.apache.phoenix.schema.tuple.Tuple;

/**
 * Iterates through tuples retrieving sequences from the server as needed
 * @since 3.0
 */
public class SequenceResultIterator extends DelegateResultIterator {
  private final SequenceManager sequenceManager;

  public SequenceResultIterator(ResultIterator delegate, SequenceManager sequenceManager)
    throws SQLException {
    super(delegate);
    this.sequenceManager = sequenceManager;
  }

  @Override
  public Tuple next() throws SQLException {
    Tuple next = super.next();
    if (next == null) {
      return null;
    }
    next = sequenceManager.newSequenceTuple(next);
    return next;
  }

  @Override
  public void explain(List<String> planSteps) {
    super.explain(planSteps);
    int nSequences = sequenceManager.getSequenceCount();
    planSteps
      .add("CLIENT RESERVE VALUES FROM " + nSequences + " SEQUENCE" + (nSequences == 1 ? "" : "S"));
  }

  @Override
  public void explain(List<String> planSteps,
    ExplainPlanAttributesBuilder explainPlanAttributesBuilder) {
    super.explain(planSteps, explainPlanAttributesBuilder);
    int nSequences = sequenceManager.getSequenceCount();
    explainPlanAttributesBuilder.setClientSequenceCount(nSequences);
    planSteps
      .add("CLIENT RESERVE VALUES FROM " + nSequences + " SEQUENCE" + (nSequences == 1 ? "" : "S"));
  }

  @Override
  public String toString() {
    return "SequenceResultIterator [sequenceManager=" + sequenceManager + "]";
  }
}
