Java PairFunction類代碼示例

import org.apache.spark.api.java.function.PairFunction; //導入依賴的package包/類
public void run() throws IOException {
  SparkConf conf = new SparkConf();
  conf.setAppName(getAppName());
  conf.set(SPARK_SERIALIZER, ORG_APACHE_SPARK_SERIALIZER_KRYO_SERIALIZER);
  JavaSparkUtil.packProjectJars(conf);
  setupSparkConf(conf);

  JavaStreamingContext ssc = new JavaStreamingContext(conf, getDuration());
  List<JavaDStream<T>> streamsList = getStreamsList(ssc);

  // Union all the streams if there is more than 1 stream
  JavaDStream<T> streams = unionStreams(ssc, streamsList);

  JavaPairDStream<String, RowMutation> pairDStream = streams.mapToPair(new PairFunction<T, String, RowMutation>() {
    public Tuple2<String, RowMutation> call(T t) {
      RowMutation rowMutation = convert(t);
      return new Tuple2<String, RowMutation>(rowMutation.getRowId(), rowMutation);
    }
  });

  pairDStream.foreachRDD(getFunction());

  ssc.start();
  ssc.awaitTermination();
}
 

import org.apache.spark.api.java.function.PairFunction; //導入依賴的package包/類
public JavaPairRDD<String, List<String>> tokenizeData(JavaPairRDD<String, String> datasetsContentRDD, String splitter) throws Exception {

    return datasetsContentRDD.mapToPair(new PairFunction<Tuple2<String, String>, String, List<String>>() {
      /**
       * 
       */
      private static final long serialVersionUID = 1L;

      @Override
      public Tuple2<String, List<String>> call(Tuple2<String, String> arg) throws Exception {
        String content = arg._2;
        List<String> tokens = getTokens(content, splitter);

        return new Tuple2<>(arg._1, tokens);
      }
    });

  }
 

import org.apache.spark.api.java.function.PairFunction; //導入依賴的package包/類
public static void main(String[] args) throws Exception {

    if (args.length < 2) {
      System.err.println("Usage: JavaTeraSort <HDFS_INPUT> <HDFS_OUTPUT>");
      System.exit(1);
    }

    SparkConf sparkConf = new SparkConf().setAppName("JavaTeraSort");
    JavaSparkContext ctx = new JavaSparkContext(sparkConf);
    JavaRDD<String> lines = ctx.textFile(args[0], 1);
    Integer parallel = sparkConf.getInt("spark.default.parallelism", ctx.defaultParallelism());
    Integer reducer  = Integer.parseInt(IOCommon.getProperty("hibench.default.shuffle.parallelism").get());
    JavaPairRDD<String, String> words = lines.mapToPair(new PairFunction<String, String, String>() {
        @Override
        public Tuple2<String, String> call(String s) throws Exception {
            return new Tuple2<String, String>(s.substring(0, 10), s.substring(10));
        }
    });


    JavaPairRDD<String, String> sorted = words.sortByKey(true, reducer);

    JavaRDD<String> result = sorted.map(new Function<Tuple2<String, String>, String>() {
        @Override
        public String call(Tuple2<String, String> e) throws Exception {
            return e._1() + e._2();
        }
    });

    result.saveAsTextFile(args[1]);

    ctx.stop();
  }
 

import org.apache.spark.api.java.function.PairFunction; //導入依賴的package包/類
private JavaPairRDD<String, String> parallizeData(SparkDriver spark, List<Tuple2<String, String>> datasetContent) {

    JavaRDD<Tuple2<String, String>> datasetContentRDD = spark.sc.parallelize(datasetContent);

    return datasetContentRDD.mapToPair(new PairFunction<Tuple2<String, String>, String, String>() {
      /**
       * 
       */
      private static final long serialVersionUID = 1L;

      @Override
      public Tuple2<String, String> call(Tuple2<String, String> term) throws Exception {
        return term;
      }
    });

  }
 

import org.apache.spark.api.java.function.PairFunction; //導入依賴的package包/類
private void addNewElement(JavaPairRDD newPair, JavaPairRDD timeStamp) {
    item2ReadCount = item2ReadCount
            .union(newPair)
            .coalesce(numPartitions, false)
            .reduceByKey((v1, v2) ->  (Long) v1 +  (Long) v2, numPartitions)
            .mapToPair((PairFunction<Tuple2<Long, Long>, Long, Long>) Tuple2::swap)
            .sortByKey(false, numPartitions)
            .mapToPair((PairFunction<Tuple2<Long, Long>, Long, Long>) Tuple2::swap);
    item2timeStampData = item2timeStampData
            .union(timeStamp)
            .coalesce(numPartitions, false)
            .reduceByKey(replaceValues)
            .mapToPair((PairFunction<Tuple2<Long, Long>, Long, Long>) Tuple2::swap)
            .sortByKey(true, numPartitions)
            .mapToPair((PairFunction<Tuple2<Long, Long>, Long, Long>) Tuple2::swap);
}
 

import org.apache.spark.api.java.function.PairFunction; //導入依賴的package包/類
/**
 * A utility method that adapts {@link PairFunction} to a {@link PairFlatMapFunction} with an
 * {@link Iterator} input. This is particularly useful because it allows to use functions written
 * for mapToPair functions in flatmapToPair functions.
 *
 * @param pairFunction the {@link PairFunction} to adapt.
 * @param <T> the input type.
 * @param <K> the output key type.
 * @param <V> the output value type.
 * @return a {@link PairFlatMapFunction} that accepts an {@link Iterator} as an input and applies
 *     the {@link PairFunction} on every element.
 */
public static <T, K, V> PairFlatMapFunction<Iterator<T>, K, V> pairFunctionToPairFlatMapFunction(
    final PairFunction<T, K, V> pairFunction) {
  return new PairFlatMapFunction<Iterator<T>, K, V>() {

    @Override
    public Iterator<Tuple2<K, V>> call(Iterator<T> itr) throws Exception {
      final Iterator<Tuple2<K, V>> outputItr =
          Iterators.transform(
              itr,
              new com.google.common.base.Function<T, Tuple2<K, V>>() {

                @Override
                public Tuple2<K, V> apply(T t) {
                  try {
                    return pairFunction.call(t);
                  } catch (Exception e) {
                    throw new RuntimeException(e);
                  }
                }
              });
      return outputItr;
    }
  };
}
 

import org.apache.spark.api.java.function.PairFunction; //導入依賴的package包/類
/**
 * A function wrapper for converting a byte array pair to a key-value pair, where
 * values are {@link Iterable}.
 *
 * @param keyCoder Coder to deserialize keys.
 * @param valueCoder Coder to deserialize values.
 * @param <K>   The type of the key being deserialized.
 * @param <V>   The type of the value being deserialized.
 * @return A function that accepts a pair of byte arrays and returns a key-value pair.
 */
public static <K, V> PairFunction<Tuple2<ByteArray, Iterable<byte[]>>, K, Iterable<V>>
    fromByteFunctionIterable(final Coder<K> keyCoder, final Coder<V> valueCoder) {
  return new PairFunction<Tuple2<ByteArray, Iterable<byte[]>>, K, Iterable<V>>() {
    @Override
    public Tuple2<K, Iterable<V>> call(Tuple2<ByteArray, Iterable<byte[]>> tuple) {
      return new Tuple2<>(fromByteArray(tuple._1().getValue(), keyCoder),
        Iterables.transform(tuple._2(), new com.google.common.base.Function<byte[], V>() {
          @Override
          public V apply(byte[] bytes) {
            return fromByteArray(bytes, valueCoder);
          }
        }));
    }
  };
}
 

import org.apache.spark.api.java.function.PairFunction; //導入依賴的package包/類
protected void publishToNats(final String subject1, final String subject2, final int partitionsNb) {
	final JavaDStream<String> lines = ssc.textFileStream(tempDir.getAbsolutePath()).repartition(partitionsNb);		
	
	JavaPairDStream<String, String> stream1 = 
			lines.mapToPair((PairFunction<String, String, String>) str -> {
								return new Tuple2<String, String>(subject1, str);
							});
	JavaPairDStream<String, String> stream2 = 
			lines.mapToPair((PairFunction<String, String, String>) str -> {
								return new Tuple2<String, String>(subject2, str);
							});
	final JavaPairDStream<String, String> stream = stream1.union(stream2);
	
	if (logger.isDebugEnabled()) {
		stream.print();
	}		
	
	SparkToNatsConnectorPool
		.newPool()
		.withNatsURL(NATS_SERVER_URL)
		.withConnectionTimeout(Duration.ofSeconds(2))
		.publishToNatsAsKeyValue(stream);
}
 

import org.apache.spark.api.java.function.PairFunction; //導入依賴的package包/類
private static <T> TransformEvaluator<TextIO.Write.Bound<T>> writeText() {
  return new TransformEvaluator<TextIO.Write.Bound<T>>() {
    @Override
    public void evaluate(TextIO.Write.Bound<T> transform, EvaluationContext context) {
      @SuppressWarnings("unchecked")
      JavaPairRDD<T, Void> last =
          ((JavaRDDLike<WindowedValue<T>, ?>) context.getInputRDD(transform))
          .map(WindowingHelpers.<T>unwindowFunction())
          .mapToPair(new PairFunction<T, T,
                  Void>() {
            @Override
            public Tuple2<T, Void> call(T t) throws Exception {
              return new Tuple2<>(t, null);
            }
          });
      ShardTemplateInformation shardTemplateInfo =
          new ShardTemplateInformation(transform.getNumShards(),
              transform.getShardTemplate(), transform.getFilenamePrefix(),
              transform.getFilenameSuffix());
      writeHadoopFile(last, new Configuration(), shardTemplateInfo, Text.class,
          NullWritable.class, TemplatedTextOutputFormat.class);
    }
  };
}
 

import org.apache.spark.api.java.function.PairFunction; //導入依賴的package包/類
/**
 * A function wrapper for converting a byte array pair to a key-value pair, where
 * values are {@link Iterable}.
 *
 * @param keyCoder Coder to deserialize keys.
 * @param valueCoder Coder to deserialize values.
 * @param <K>   The type of the key being deserialized.
 * @param <V>   The type of the value being deserialized.
 * @return A function that accepts a pair of byte arrays and returns a key-value pair.
 */
static <K, V> PairFunction<Tuple2<ByteArray, Iterable<byte[]>>, K, Iterable<V>>
    fromByteFunctionIterable(final Coder<K> keyCoder, final Coder<V> valueCoder) {
  return new PairFunction<Tuple2<ByteArray, Iterable<byte[]>>, K, Iterable<V>>() {
    @Override
    public Tuple2<K, Iterable<V>> call(Tuple2<ByteArray, Iterable<byte[]>> tuple) {
      return new Tuple2<>(fromByteArray(tuple._1().getValue(), keyCoder),
        Iterables.transform(tuple._2(), new com.google.common.base.Function<byte[], V>() {
          @Override
          public V apply(byte[] bytes) {
            return fromByteArray(bytes, valueCoder);
          }
        }));
    }
  };
}
 

import org.apache.spark.api.java.function.PairFunction; //導入依賴的package包/類
@SuppressWarnings("serial")
@Override
public SortedCounts<String> execute(final JavaSparkContext spark) {
	final JavaRDD<String> textFile = spark.textFile(inputFile);
	final JavaRDD<String> words = textFile.flatMap(new FlatMapFunction<String, String>() {
		@Override
		public Iterable<String> call(final String rawJSON) throws TwitterException {
			final Status tweet = TwitterObjectFactory.createStatus(rawJSON);
			String text = tweet.getText();
			return Arrays.asList(text.split(" "));
		}
	});
	final JavaPairRDD<String, Integer> pairs = words.mapToPair(new PairFunction<String, String, Integer>() {
		@Override
		public Tuple2<String, Integer> call(final String s) {
			return new Tuple2<String, Integer>(s.toLowerCase(), 1);
		}
	});
	final JavaPairRDD<String, Integer> counts = pairs.reduceByKey(new Function2<Integer, Integer, Integer>() {
		@Override
		public Integer call(final Integer a, final Integer b) {
			return a + b;
		}
	});
	return SortedCounts.create(counts);
}
 

import org.apache.spark.api.java.function.PairFunction; //導入依賴的package包/類
/**
 * Spatial partitioning without duplicates.
 *
 * @return true, if successful
 * @throws Exception the exception
 */
private boolean spatialPartitioningWithoutDuplicates() throws Exception
{
    this.distributedRasterColorMatrix = this.distributedRasterColorMatrix.mapToPair(new PairFunction<Tuple2<Pixel, Integer>, Pixel, Integer>() {
        @Override
        public Tuple2<Pixel, Integer> call(Tuple2<Pixel, Integer> pixelDoubleTuple2) throws Exception {
            Pixel newPixel = new Pixel(pixelDoubleTuple2._1().getX(),pixelDoubleTuple2._1().getY(),resolutionX,resolutionY);
            newPixel.setDuplicate(false);
            newPixel.setCurrentPartitionId(VisualizationPartitioner.CalculatePartitionId(resolutionX,resolutionY,partitionX, partitionY, pixelDoubleTuple2._1.getX(), pixelDoubleTuple2._1.getY()));
            Tuple2<Pixel,Integer> newPixelDoubleTuple2 = new Tuple2<Pixel, Integer>(newPixel, pixelDoubleTuple2._2());
            return newPixelDoubleTuple2;
        }
    });
    this.distributedRasterColorMatrix = this.distributedRasterColorMatrix.partitionBy(new VisualizationPartitioner(this.resolutionX,this.resolutionY,this.partitionX,this.partitionY));
    return true;
}
 

import org.apache.spark.api.java.function.PairFunction; //導入依賴的package包/類
public static void main(String[] args) {
	
	SparkConf sparkConf = new SparkConf();
	sparkConf.setMaster("local");
	sparkConf.setAppName("TestSpark");
	
	JavaSparkContext sc = new JavaSparkContext(sparkConf);
	JavaRDD<String> input = sc.parallelize(data);
	
	JavaPairRDD<String, String> inputPair = input.mapToPair(
			new PairFunction<String, String, String>() {
				@Override
				public Tuple2<String, String> call(String x)	throws Exception {
					return new Tuple2<String, String>(x.split(" ")[0], x);
				}
			}
	);
	
	System.out.println(inputPair.take(100));

	
}
 

import org.apache.spark.api.java.function.PairFunction; //導入依賴的package包/類
@Before
public void before() throws Exception {

    queryExecutor = new QueryExecutor(deepContext, deepConnectionHandler);

    // Stubs
    when(deepConnectionHandler.getConnection(CLUSTERNAME_CONSTANT.getName())).thenReturn(deepConnection);
    when(deepConnection.getExtractorConfig()).thenReturn(extractorConfig);
    when(extractorConfig.clone()).thenReturn(extractorConfig);
    when(deepContext.createJavaRDD(any(ExtractorConfig.class))).thenReturn(singleRdd);
    when(deepContext.createHDFSRDD(any(ExtractorConfig.class))).thenReturn(rdd);
    when(rdd.toJavaRDD()).thenReturn(singleRdd);
    when(singleRdd.collect()).thenReturn(generateListOfCells(3));
    when(singleRdd.filter(any(Function.class))).thenReturn(singleRdd);
    when(singleRdd.map(any(FilterColumns.class))).thenReturn(singleRdd);
    when(singleRdd.mapToPair(any(PairFunction.class))).thenReturn(pairRdd);
    when(singleRdd.keyBy(any(Function.class))).thenReturn(pairRdd);
    when(pairRdd.join(pairRdd)).thenReturn(joinedRdd);
    when(pairRdd.reduceByKey(any(Function2.class))).thenReturn(pairRdd);
    when(pairRdd.map(any(Function.class))).thenReturn(singleRdd);
    when(joinedRdd.map(any(JoinCells.class))).thenReturn(singleRdd);


}
 

import org.apache.spark.api.java.function.PairFunction; //導入依賴的package包/類
@SuppressWarnings("serial")
private static final PairFunction<Integer, Integer, Integer> convertToKeyValue() {

  /**
   * Convert to key-value [key (integer) : value (integer * integer)]
   */
  return new PairFunction<Integer, Integer, Integer>() {

    @Override
    public final Tuple2<Integer, Integer> call(final Integer integer) throws Exception {

      /* Tuple : key (integer) : value (integer * integer) */
      return new Tuple2<Integer, Integer>(integer, integer * integer);
    }
  };
}