Scanner.java

/*
 * Copyright © 2014 Cask Data, Inc.
 *
 * 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 co.cask.cdap.api.dataset.table;

import javax.annotation.Nullable;

/**
 * Interface for table scan operation.
 */
public interface Scanner {

  /**
   * Returns the next row or {@code null} if the scanner is exhausted.
   */
  @Nullable
  Row next();

  /**
   * Closes the scanner and releases any resources.
   */
  void close();

}