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 com.aliyun.odps.graph.local;
  
  import java.io.Closeable;
  import java.io.IOException;
  
  /**
   * The record reader breaks the data into key/value pairs for input to the
   * {@link Mapper}.
   *
   * @param <KEYIN>
   * @param <VALUEIN>
   */
  public abstract class BaseRecordReader<KEYIN, VALUEIN> implements Closeable {
  
    /**
     * Read the next key, value pair.
     *
     * @return true if a key/value pair was read
     * @throws IOException
     * @throws InterruptedException
     */
    public abstract boolean nextKeyValue() throws IOException;
  
    /**
     * Get the current key
     *
     * @return the current key or null if there is no current key
     * @throws IOException
     * @throws InterruptedException
     */
    public abstract KEYIN getCurrentKey() throws IOException;
  
    /**
     * Get the current value.
     *
     * @return the object that was read
     * @throws IOException
     * @throws InterruptedException
     */
    public abstract VALUEIN getCurrentValue() throws IOException;
  
    /**
     * The current progress of the record reader through its data.
     *
     * @return a number between 0.0 and 1.0 that is the fraction of the data read
     * @throws IOException
     * @throws InterruptedException
     */
    public abstract float getProgress() throws IOException;
  
    /**
     * Close the record reader.
     */
    public abstract void close() throws IOException;
  }
  