/**
 * Copyright (C) 2014-2016 LinkedIn Corp. (pinot-core@linkedin.com)
 *
 * Licensed 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 com.linkedin.pinot.core.operator;

import com.linkedin.pinot.core.common.Block;
import com.linkedin.pinot.core.common.BlockId;
import com.linkedin.pinot.core.common.Operator;
import com.linkedin.pinot.core.util.trace.TraceContext;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;


/**
 * Any other Pinot Operators should extend BaseOperator
 */
public abstract class BaseOperator implements Operator {
  private static final Logger LOGGER = LoggerFactory.getLogger(BaseOperator.class);

  @Override
  public final Block nextBlock() {
    long start = System.currentTimeMillis();
    Block ret = getNextBlock();
    long end = System.currentTimeMillis();
    LOGGER.trace("Time spent in {}: {}", getOperatorName(), (end - start));
    TraceContext.logLatency(getOperatorName(), (end - start));
    return ret;
  }

  @Override
  public final Block nextBlock(BlockId blockId) {
    long start = System.currentTimeMillis();
    Block ret = getNextBlock(blockId);
    long end = System.currentTimeMillis();
    LOGGER.trace("Time spent in {}: {}", getOperatorName(), (end - start));
    TraceContext.logLatency(getOperatorName(), (end - start));
    return ret;
  }

  public abstract Block getNextBlock();

  public abstract Block getNextBlock(BlockId blockId);

  // Enforcing sub-class to implement the getOperatorName(), as they can just return a static final,
  // as opposed to this super class calling getClass().getSimpleName().
  public abstract String getOperatorName();

  @Override
  public ExecutionStatistics getExecutionStatistics() {
    throw new UnsupportedOperationException();
  }
}